from causes to consequences: understanding the …
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FROM CAUSES TO CONSEQUENCES: UNDERSTANDING THE IMPACTS OF PERMAFROST THAW AS AN INTEGRATED SYSTEM
by
Carolyn Gibson
A Thesis
presented to
The University of Guelph
In partial fulfilment of requirements for the degree of
Doctor of Philosophy
in
Integrative Biology
Guelph, Ontario, Canada
© Carolyn Gibson, April, 2021
ABSTRACT
FROM CAUSES TO CONSEQUENCES: UNDERSTANDING THE IMPACTS OF PERMAFROST THAW ON THE PROVISIONING OF ECOSYSTEM SERVICES AND
HUMAN-WELLBEING
Carolyn Gibson University of Guelph, 2021
Advisor(s): Dr. Karl Cottenie Dr. Merritt Turetsky
Understanding the causes and consequences of permafrost thaw is one of the key
challenges facing northern communities and researchers today. With northern
environments warming at twice the global average, climate change is driving
widespread changes in permafrost environments that provide the foundation for
ecological-, social-, economic-, and human-wellbeing. In this thesis I aim to enhance the
understanding of permafrost environments as an integrated system that considers
humans and communities as part of the permafrost system. In chapter 1, I conduct a
scoping review of permafrost peer-reviewed literature related to the consequences of
permafrost thaw. I show that over 95% of the literature focuses on permafrost thaw
impacts to ecosystem processes and that over 75% of northern communities lack
permafrost thaw related measurements within 75km of them. In Chapter 2, I quantify the
consequences of permafrost thaw on land-users. I show that permafrost thaw accounts
for a third, and potentially as much as a half of all hazards that land-users faces when
on the land. In chapter 3, I respond to an emergent challenge from chapter 2 about the
need for permafrost vulnerability data at a scale that is more relevant to community-
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level planning. I map the spatial distribution of terrain vulnerable permafrost thaw at a
scale that is relevant to community adaptation planning. Data generated in chapter 3
are then used in chapter 4 where I assess how the degree of thermokarst formation
within permafrost peatlands varies across a latitudinal (climatic) gradient (i.e., space-for-
time substitutions) to make inferences about how thaw will progress in a warming
climate. I show that at northern latitudes, peatland permafrost remains climate-protected
with relatively little thaw. Conversely, I show that at the southern latitudes, widespread
thaw has occurred with areas of lower elevation being most vulnerable. Overall, the
findings of this thesis show the importance of considering communities and their needs
at the forefront of any permafrost related study. When done, not only does an enhanced
and enriched understanding of the permafrost system emerge, but the knowledge and
information generated is more easily accessed and applied by communities and
decision makers.
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ACKNOWLEDGEMENTS
I would like to thank the Dehcho First Nations and the Sahtu Dene First Nation
and Metis Nation who welcomed us into their territories to conduct this research and
whose histories, languages, and vibrant cultures continue to influence our research.
This body of work is a culmination of the passion and efforts of a great number of
people, without whom I would never have completed this thesis. I would like to thank the
following people for not only their help, but for making life as a graduate student more
than just research. I would like to thank them all for making it an experience that has
allowed me to grow in unexpected ways, has caused me to see the world through a new
and different lens, and most importantly, has caused me to grow and become a better
person.
I would like to thank my advisor Dr. Merritt Turetsky for her guidance, unwavering
passion for research, and for taking a risk by letting me to tackle the interdisciplinarity
found within this thesis. I am so grateful for being allowed to spread my wings and
explore many elements of my discipline, knowing that there was always someone there
to catch me if I fell. To Dr. Karl Cottenie, I would like to thank him for supporting me
through the transition of Merritt to another institution. He made what could have been a
rocky transition incredibly smooth and was always willing to read ‘that shitty first draft’ to
help put me on the right path. I am also grateful to my thesis committee members, Dr.
Laura Chasmer and Dr. Todd Brinkman whose diverse backgrounds helped shape me
into a well-rounded interdisciplinary scientist.
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To my lab mates, field comrades, and on-the-land camp individuals I thank you
for your continued interest in and support of my work. To the girls of the
‘commonwealth’, I thank you for being the never ending lifeline of support to bounce
ideas off of, get feedback on my colour palettes for figures, and listen to all my
complaints and hardships as I worked my way through this degree. A special thank-you
to soon to be, Dr. McKenzie Kuhn whose supporting words, never ending
encouragement, and belief in me when I didn’t have belief in myself . You helped me to
never give up on myself, and make it to the finish line.
I would like to thank those funding agencies without whom this work would not
have been possible. To NASA ABoVE program (NASA: NNX15AT72A) and the National
Science Foundation (NSF: 1518563), Climate Change Preparedness Program,
Environment and Natural Resources, Government of the Northwest Territories, National
Science and Engineering Council of Canada, the Northwest Territories Cumulative
Impact Monitoring Program, and CFREF Global Water Futures project Northern Water
Futures, and Wilfrid Laurier University, and the Northern Scientific Training Program
thank you for believing in the work I was doing.
Finally, I would like to extent the biggest, most heartfelt thank you to my best
friend, partner-in-crime, and all-around favorite human, Gaetan Lamarre. Without your
constant support and encouragement, this research would not have been possible. You
kept me balanced and helped keep me focused on the things in life that are most
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important. No matter what I was going through, you were always there with a smile and
cuddle to make everything better. You earned this PhD just as much I did.
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TABLE OF CONTENTS
Abstract ..................................................................................................................................ii
Acknowledgements............................................................................................................... iii
Table of Contents................................................................................................................. vi
List of Tables ........................................................................................................................ xi
List of Figures.......................................................................................................................xii
List of Appendices ............................................................................................................. xvi
1 Chapter 1: Introduction ................................................................................................. 1
1.1 Climate Change at High Latitudes ......................................................................... 1
1.2 Background on permafrost: Characteristics, distributions, and landforms .......... 2
1.3 Permafrost Change: causes ................................................................................... 3
1.4 Permafrost change: climatic, ecological and social consequences ..................... 5
1.5 Thesis Objectives .................................................................................................... 7
1.6 Chapter Publications and Author Contributions .................................................... 8
1.7 References .............................................................................................................. 9
2 Adding social dimensions to our understanding of permafrost as an integrative system ................................................................................................................................. 15
2.1 Introduction ............................................................................................................ 15
2.2 Results and Discussion ........................................................................................ 16
2.3 Conclusion ............................................................................................................. 25
2.4 Methods ................................................................................................................. 26
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2.4.1 Review and assessment of the current state of knowledge on an integrated permafrost system ....................................................................................................... 26
2.4.2 Literature Searching, Screen, and Extraction............................................... 27
2.4.3 Development of an integrated permafrost system conceptual model ......... 28
2.4.4 Spatial distribution of permafrost related measurements ............................ 28
2.5 References ............................................................................................................ 29
3 Identifying increasing risks of hazards for northern land-users caused by permafrost thaw: integrating top-down and bottom-up research approaches.................................... 33
3.1 Abstract.................................................................................................................. 33
3.2 Introduction ............................................................................................................ 33
3.2.1 Knowledge Integration ................................................................................... 33
3.2.2 Permafrost as a integrated system ............................................................... 35
3.3 Methods ................................................................................................................. 36
3.3.1 Study Region, community partnerships, and data collection. ...................... 36
3.3.2 Identifying permafrost-driven hazards from bottom-up knowledge sources and determining how permafrost-driven hazards affected land-users and their
safety 38
3.3.3 Quantifying the extent of and potential for permafrost-driven hazards from top-down knowledge sources ..................................................................................... 39
3.4 Results ................................................................................................................... 40
3.4.1 Identification of permafrost-driven hazards .................................................. 40
3.4.2 Determination of how permafrost-driven hazards affected land-users and their safety ................................................................................................................... 41
3.4.3 Quantification of the extent of and potential for permafrost-driven hazards 43
3.5 Discussion ............................................................................................................. 46
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3.6 Conclusion ............................................................................................................. 48
3.7 References ............................................................................................................ 48
4 Thermokarst Mapping Collective: Protocol for organic permafrost terrain and preliminary inventory from the Taiga Plains test area, Northwest Territories.................. 57
4.1 Abstract.................................................................................................................. 57
4.2 Introduction ............................................................................................................ 57
4.3 Background ........................................................................................................... 58
4.3.1 Permafrost and thermokarst .......................................................................... 58
4.3.2 Organic permafrost terrain and related thermokarst .................................... 60
4.4 Taiga Plains Test Area ......................................................................................... 63
4.5 Methodology .......................................................................................................... 65
4.5.1 Sentinel-2 satellite imagery, processing, and spatial extent........................ 65
4.5.2 Area of interest and mapping grid ................................................................. 65
4.5.3 Identifying organic permafrost terrain and associated thermokarst features on Sentinel-2 imagery ................................................................................................. 66
4.5.4 Identifying peat plateau complexes and percent cover................................ 68
4.5.5 Forested versus unforested peat plateaus ................................................... 69
4.5.6 Fire History ..................................................................................................... 70
4.5.7 Degree of thermokarst degradation .............................................................. 71
4.5.8 Populating the dataset ................................................................................... 72
4.6 Results ................................................................................................................... 75
4.6.1 Taiga Plains Test Area Results ..................................................................... 75
4.6.2 Quality assessment........................................................................................ 77
4.7 Limitations ............................................................................................................. 79
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4.7.1 Data ................................................................................................................ 79
4.7.2 Mapping .......................................................................................................... 79
4.8 Digital Data ............................................................................................................ 81
4.9 Summary ............................................................................................................... 81
4.10 References......................................................................................................... 82
5 Mapping and understanding the vulnerability of northern peatlands to permafrost thaw at scales relevant to community adaptation planning .............................................. 86
5.1 Abstract.................................................................................................................. 86
5.2 Introduction ............................................................................................................ 87
5.3 Study Area ............................................................................................................. 90
5.4 Methods ................................................................................................................. 92
5.4.1 Updating permafrost peatland vulnerability maps at local scales ............... 92
5.4.2 Assessment of the degree of thermokarst formation across a latitudinal gradient ........................................................................................................................ 93
5.4.3 Elevational controls on thermokarst formation ............................................. 95
5.5 Results ................................................................................................................... 96
5.5.1 Proportion of peatland complex that has thawed across a latitudinal gradient ........................................................................................................................ 96
5.5.2 Elevational controls on thermokarst formation ............................................. 98
5.6 Discussion ............................................................................................................. 98
5.6.1 Updated permafrost peatland vulnerability map........................................... 98
5.6.2 Thawed permafrost peatland areas with variation in latitude and elevational controls ...................................................................................................................... 101
5.6.3 Conclusion .................................................................................................... 103
5.7 References .......................................................................................................... 104
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6 Conclusion ................................................................................................................. 110
Appendices........................................................................................................................ 114
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LIST OF TABLES
Table 1.1: Examples of actions that can be taken by various actors within the permafrost research community in response to our call-to-action………………………. 23
Table 1.2: Attributes and inputs for the sub-grid cell classification of peat plateau complexes………………………………………………………………………………………74
Table 1.3: Sub-grid cell permafrost peatland complex area bins and midpoints……….75
Table 1.4: Mapping results for sub-grid cell DQ163……………………………………….76
Table 1.4: Estimated extent (number of grid cells) of permafrost peatland complex in total, forested, and unforested landscapes (total n=12 177)…………………………...…77
Table 1.5: Table 5. Error matrix resulting from estimating percent extent of peat plateau complex in randomly sampled sub-grid cells (3.75 km × 3.75 km). Bins are estimates of percent cover…………………………………………………………………………………...............79
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LIST OF FIGURES
Figure 2.1: Conceptual model of the impacts of permafrost thaw, classified as processes, services, or societal well-being. This represents an integrative permafrost change system that views the impacts of thaw across all these levels. .......................... 18
Figure 2.2: Number of permafrost thaw-related publications per year, grouped by publication type as it relates to ecosystem process, services, and human well-being. .. 19
Figure 2.3: A) Proportion of permafrost thaw studies by country. B) Of the studies located within each county, the proportion that focused on ecosystem process,
ecosystem service, and human wellbeing. Ecosystem process work dominated nearly all countries, with the percentage of process-based work shown in the circle................ 19
Figure 2.4: Permafrost-thaw measurement locations were extracted from studies located within Canada and Alaska (black dots). A heat map is then applied to identify
areas of high and low densities of permafrost measurements. Emphasis is placed on the relative colours for density, as opposed to shape and size as the map is projected in Mercator Auxiliary Sphere causing distortions to the shape of the heat maps. Green areas represent areas of higher permafrost measurement concentrations, while red
represents fewer. Communities located within the permafrost zone and shown (blue triangle)30. Just over 75% of communities within the permafrost zone lack permafrost measurements within 75 km of them. ................................................................................ 21
Figure 3.1: Conceptual model of the attributes of top-down and bottom-up knowledge
sources and the emergent properties from the integration of these two knowledge sources. ............................................................................................................................... 35
Figure 3.2: Yukon River basin study area outlined in black with nine partner communities. Hazard locations identified by land-users shown in green circles. Only a
subset of the hazard locations (n=184/442) that have been approved for publication by the land-users are shown. These are underlain with the Olefeldt et al. (2016) permafrost thaw probability data. Base map provided by Esri, DigitalGlobe, Geo eye (ArcGIS version 10.3). ...................................................................................................................... 38
Figure 3.3: Example of hazards encountered by land-users while on the land that were ‘highly likely’ or ‘likely’ to be caused by permafrost thaw. A) Lake edge erosion encroaches on a travel route. The land-users will soon need to reroute the trail. B) Riverbank thaw increases river sediment load and trees dislodged into the river become
a hazard for motor boats. C) Above-zero soils in the winter cause changes to hydrology and inhibit freeze-up of snowmobile routes. D) and E) Thawing soils create muddy trails that impede ATV travel. ...................................................................................................... 41
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Figure 3.4: Proportion of hazards that were highly likely, likely, unlikely to be caused by permafrost thaw (including unknown) based on the land-user’s photos and descriptions, and expert determination of relation to permafrost thaw (a). The proportion of subsistence use areas that is covered by each thaw vulnerability class based on the
Olefeldt et al. (2016) dataset (b). Results are reported for all communities combined as well as for road-connected communities and remote communities. ................................ 43
Figure 3.5: Permafrost thaw probability in the modeled subsistence-use area for each community (Olefeldt et al. 2016; Brown et al. in prep). Subset of hazard locations that
have been approved by land-users are shown. Base map provided by Esri, National Geographic, Geo eye (ArcGIS version 10.3). ................................................................... 45
Figure 4.1: a) Example of permafrost peat plateau complex (61°14'6.79"N, 117°35'23.81"W) in World View 2 imagery. Peat plateaus (medium green with ‘salt and
pepper’ texture) represent areas where the permafrost is intact, while fen and/or bog areas (light to golden brown with comparatively homogeneous texture) are those in which permafrost thaw (thermokarst) has occurred. b) Example of polygonal permafrost peatland (68°1'41.97"N, 132°38'51.45"W) in continuous permafrost in World View 2
imagery. Peat plateaus (white due to lichen coverage) are crisscrossed with polygonal troughs................................................................................................................................. 60
Figure 4.2: Map of the Taiga Plains test area within the NWT (322 340 km2). The bottom left inset shows the location of the study area relative to northern Canada. ...... 64
Figure 4.3: The Thermokarst Collective study area comprises NWT and shared watershed boundaries. Grids represent 15 km × 15 km areas of interest (AOI)............. 67
Figure 4.4: Gridded mapping methodology and naming convention. The 15 km × 15 km grid cells were subdivided into 7.5 km × 7.5 km grid cells and then again into 3.75 km ×
3.75 km grid cells for mapping organic permafrost terrain. .............................................. 68
Figure 4.5: Figure 5. Examples of peat plateau complexes for the suite of mapped attributes: spatial extent, vegetation cover, and fire history. ............................................ 69
Figure 4.6: Example of a) a permafrost peatland complex (61°14'6.79"N,
117°35'23.81"W), and b) an unforested permafrost peatland complex (64°53'16.04"N, 126°34'54.18"W). ................................................................................................................ 70
Figure 4.7: Example for a) recently burned permafrost peatland complex (60°40'44.13"N, 117°41'59.12"W) and b) a historically burned permafrost peatland (Fire
year = 2008, 63°29'2.05"N, 120°34'32.51"W). Forested peat plateaus that burned recently are brownish-green, brown to dark brown, or black, while unforested peat plateaus take on a grey colour. .......................................................................................... 71
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Figure 4.8: The degree of degradation (thermokarst) is categorized into three categories a) high (67% – 100%, 60°42'25.86"N, 117°52'33.62"W), b) medium (34% – 66%, 63°15'51.34"N, 121°46'44.66"W), and c) low (0% – 33%, 65°19'26.83"N, 124°56'32.56"W). ................................................................................................................ 72
Figure 4.9: Density distribution of peat plateau complexes in the discontinuous permafrost zone of the Taiga Plains. Data are shown according to both a) sub-grid cell size (3.75 km × 3.75 km) and b) grid cell size (7.5 km × 7.5 km). ................................... 76
Figure 4.10: Degree of degradation (thermokarst) of the permafrost peatland
complexes. Visually estimated as low (0% – 33%), moderate (34% – 67%), or High (67% – 100%). .................................................................................................................... 77
Figure 5.1: A) Map of study region (372 220 km2), representing the extent of the discontinuous permafrost zone within the Taiga Plains Ecozone with the Northwest
Territories, Canada. Variation in elevation across the study region is shown (CDEM – Natural Resources Canada, 2016). Communities across the study region reside in elevationally different positions, and community land users interact with these elevational conditions as they travel across the landscape. Base maps provided by Esri,
DigialGlobe, Geo eye (ArcGIS version 10.3). The bottom left inset shows the location of the study area relative to northern Canada. B) Example permafrost peatland complex (61°14'6.79"N, 117°35'23.81"W). Peat plateaus represent areas where the permafrost is intact, while thermokarst areas are those in which abrupt permafrost thaw (thermokarst)
has occurred. Peatland complex area = peat plateau area + thermokarst area. GeoEye satellite image obtained online https://zoom.earth............................................................ 90
Figure 5.2: Process of estimating the extent of thermokarst formation within selected 3.75 × 3.75 km grid cell. A) random selection of ‘high’ or ‘very high’ classified grid cells
across the study area. B) selection 10 random sub-grid cells 375 × 375 m in size. C) Visual percent estimates of thermokarst bog within the sub grid cell. ............................. 95
Figure 5.3: Map showing the density distribution of permafrost peatlands in the discontinuous permafrost zone of the Taiga Plains. Data are shown according to grid
cell size 3.75 × 3.75 km. ..................................................................................................... 96
Figure 5.4: A) Relationship between latitude and the proportion of peatland complexes that have thawed due to thermokarst formation. Colour represents mean annual air temperature (Fick and Hijmans 2017). Inset figure shows the proportion of peatland
complex’s thawed in three latitudinal bins that are significantly different from each other in their proportion thaw. B) Proportion of peatland complex thawed binned by latitudinal classes; data also are visualized by elevation. Larger light green dots represent higher elevations while smaller dark green dots represent lower elevations. ............................. 97
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Figure 5.5: Comparison of geospatial products of lowland thermokarst probability in permafrost peatlands in the discontinuous permafrost zone of the Taiga Plains Ecozone within the Northwest Territories, Canada. (A) The Olefeldt et al. (2016) framework was developed for use at circumpolar scales. (B) Results from this study uses a gridded
approach and was developed for use at regional or community-relevant scales. (C) Comparison of these two approaches binned by predisposition classes. Note that a negligible class does not exist within the Olefeldt et al. (2016) framework; thus we combined the “none” and “negligible” classes in this analysis. For larger versions of the
maps see Gibson et al. (2020). ........................................................................................ 100
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LIST OF APPENDICES
Supplementary Table 1: Complete list of compiled papers and their topics.
Supplementary Table 2: Proportion of studies by permafrost thaw related impact
Supplementary Figure 1: Details of the review process according to the Preferred
Supplemental 1: Search strings used
Supplemental 2: Additional methods
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1 Chapter 1: Introduction
1.1 Climate Change at High Latitudes
Climate change at high latitudes is causing rapid and unprecedented
environmental change (Chapin 2005). The rate of warming across the Arctic has been
twice that of the global average in recent decades (Bekryaev et al. 2010; Christensen et
al. 2013; Jeffries et al. 2013). The future impacts of climate warming on communities
and infrastructure is one of the most pressing issues facing northern Canada today
(GNWT 2018). Many impacts of climate warming in northern latitudes area are
associated with changes in permafrost conditions (Nelson et al 2001). It is predicted that
by the mid-21st century, the area of permafrost in the northern hemisphere will decline
by 20 – 35 % (IPCC 2018).
Northern regions are more sensitive to changes in the planet’s climate than lower
latitudes, with the Arctic currently warming at twice the rate of the rest of the planet
(Bekryaev et al 2010; IPCC 2018). The primary cause of this phenomenon is the ice-
albedo feedback, whereby melting ice uncovers darker land or ocean, which absorbs
more sunlight, causing more heating (Screen and Simmonds 2010). This represents a
positive feedback in which the impacts of small disturbance on a system include an
increase in the magnitude of the perturbation (Zuckerman & Jefferrson 1996).
Rapid warming across the north is driving widespread changes to ecological and social
systems. Warming is causing winter freeze-up to occur later, spring thaw earlier, and
traditional and local knowledge suggests travel on the land is becoming more
dangerous and challenging (GNWT 2018). Climate change is impacting water quality
and quantity through extreme weather events, changes in flood or drought severity,
changing biogeochemical properties and health of the water for wildlife and humans
(Connon et al. 2014, Gordon et al. 2016, Tank et al. 2016, Burd et al. 2018).
Widespread shifts in vegetation and expansions of the tree line northward into the
tundra have been observed (Moffat et al. 2016, Sniderhan and Baltzer 2016, Walker et
al. 2018). In the southern boreal parts of the Northwest Territories, changing fire
2
regimes are causing wildfire to become more frequent and severe, and is changing the
composition of boreal forests (Flannigan et al. 2013, Whitman et al. 2018). Of particular
concern for northern communities is the impacts that permafrost thaw will have on
ecosystems and sociocultural systems.
1.2 Background on permafrost: Characteristics, distributions, and landforms
Permafrost is defined as subsurface earth materials (soil, rock, or sediment) that
remains below 0C for two or more consecutive years (Brown and Péwé 1973;
Wasburn 1980) and underlies about 22% of the Earth’s land surface and nearly half of
the Canadian landmass (Brown et al 2002). Permafrost is classified into three zones:
continuous (more than 80% ground is permafrost), discontinuous (30 - 80%), and
sporadic (less than 30% and at high altitudes) (Brown and Péwé 1973; Brown et al
2002).
Across the entire permafrost region, the ground is characterized by two main
layers: the active layer that thaws every summer and refreezes in the winter, and the
underlying permafrost that remains below 0ºC year-round (Jorgenson et al 2006). Active
layer thickness ranges from less than 80 cm in tundra soils, to over 150 cm in the
southern limits (Nixon 2000, Nixon et al 2003, Gibson et al 2018) and is associated with
changes in mean annual air temperature. Permafrost at any point in time is a product of
both the present climate and colder climates that have prevailed during climatic
variations over the past hundreds of thousands of years (Brown and Péwé 1973).
Additionally, permafrost is a product of its biophysical environment, which explains why
permafrost can exist where mean annual air temperatures exceed 2ºC (Shur and
Jorgenson 2007). In the southern extent of the permafrost zone, permafrost is
ecosystem-driven (Jorgenson et al. 2003). Ecosystem-driven permafrost tends to be
found in poorly drained, low-lying, or north facing landscape conditions that insulate the
permafrost from warmer air temperatures. These landscape positions are associated
3
with thick peat layers and other factors that contribute to ecosystem-protection of
permafrost, particularly in peatlands (Jorgenson et al. 2010).
1.3 Permafrost Change: causes
As global temperatures increase, permafrost is increasingly vulnerable to thaw
(IPCC 2018), particularly in its southern extent where much of the permafrost persists at
temperatures just below 0ºC (Yoshikawa et al 2002). The impact of climate change on
permafrost can be indirect because permafrost is a component of a complex set of geo-
ecological feedbacks. An increase in the active layer thickness is regarded as an initial
response of permafrost to global warming (Shiklomanov et al 1999; Romanovsky et al
2002, Smith et al 2005). In the context of global change, the thickness and distribution
of the active layer may be influenced by interactions among climate, topography, land
cover, and land use at various spatial scales (Shiklomanov et al. 1999). Disturbance
events, such as wildfire, have also been shown to be impact active layer depths,
causing depths to increase as much as three-times post fire (Viereck et al 2008, Gibson
et al 2018).
Permafrost thaw can also occur through the thawing of massive ground-ice that
leads to subsidence (Pewe 1983), and deformation of the entire soil column, referred to
as thermokarst formation (Pewe 1983, Schuur et al 2009, Jones et al 2015). In contrast
to active layer deepening, thermokarst formation occurs at discrete locations due to
interactions of hydrology, soil properties, vegetation, geomorphology, and surface
disturbance (Viereck et al 2008). Additionally, thermokarst formation occurs on a very
different time scale compared to active layer thickening, loosing meters of permafrost
over months as opposed to centimeters of loss over decades (Kokelj and Jorgenson
2013). Fundamentally, thermokarst formation depends on the presence of excess
ground ice that causes characteristic land surface subsidence upon thaw (Morgenstern
et al 2011, Kokelj and Jorgenson 2013). Thermokarst formation can manifest itself in
numerous different forms depending upon the ecosystem type in which it occurs
4
(Jorgenson et al 2006, Kokelj and Jorgenson 2013). Within the Northwest Territories,
where 65-90% of the landmass is occupied by sporadic and discontinuous permafrost
that is actively thawing (GNWT 2018), wetland thermokarst events are of great interest,
and are becoming increasingly present on the landscape (Baltzer et al 2014, Gibson et
al 2018).
Wetland thermokarst is a broad term used to encompass all forms of abrupt
permafrost thaw in organic-rich terrain (peatlands). Wetland thermokarst landscapes are
common to lowland peatland environments and are characterized by the conversion of
permafrost peat mounds to permafrost-free bogs and shallow open water wetlands
(Zoltai and Tarnocai 1974). Permafrost peatlands, exist within a dynamic stable state
where they undergo a cycle of degrading and aggrading over an approximate 500-year
period (Zoltai 1993). During the degradation phase, ice has accumulated to a point
where the peat can no longer cover the surface (Seppala 1986). This causes surface
cracks that create deep fissures and allow warm air and rain to reach the frozen core
and initiate thawing (Zoltai 1993). As thawing progresses, the land subsides, increasing
the saturation of the surface peat as it begins to fall into or below the rooting zone.
Black spruce, the dominant tree species on peat plateaus, cannot tolerate these
waterlogged, low-oxygen conditions (Islam and Macdonald 2004) in the rooting zone
and begin to die. Loss of black spruce is accompanied by Sphagnum fuscum,
characteristic of the dry peat plateaus, being gradually replaced by Sphagnum
angustifolium then by Sphagnum riparium as subsistence continues and the water table
approaches the surface of the peat (Gignac et al 1991, Zoltai 1993).
During the aggradation phase, the newly thawed thermokarst bogs are
dominated by Sphagnum riparium, a highly productive moss in the waterlogged
conditions, that begins to rapidly accumulate biomass. This biomass accumulation
causes the ground surface to rise above the water table. When the water table is ~ 5 –
15 cm below the surface Sphagnum riparium is replaced by Sphagnum angustifolium
creating drier conditions and continued rising of the surface above the water table.
5
When the water table is 15 - 30 cm below the surface, Sphagnum fuscum becomes the
most abundant moss species. Due to the increasingly dry conditions created by
Sphagnum fuscum, black spruce and lichen establishment can occur. As a result of
decreasing surface moisture, the central frozen core from the previous winters fails to
thaw in the summer thus allowing for the core to expand with each successive winter.
This creates a positive feedback system in which the rising surface cools more easily
and is therefore able to accumulate ice more quickly (Zoltai 1993).
The degradation of these permafrost peat complexes/features can be triggered
by both natural and catastrophic events (Zoltai 1993). Rates of wetland thermokarst
expansion have been measured at 0.26 – 0.34% plateau loss per year (Chasmer et al
2010, Baltzer et al 2014, Gibson et al 2018) in undisturbed sites, while expansion rates
are three-fold faster in disturbed areas (Gibson et al 2018). Historically it was believed
that the rate of aggregation and degradation of permafrost peat plateaus were in
balance and these systems were in dynamic equilibrium (Zoltai 1993). However, due to
the cumulative impacts of warming and increasing disturbances such as fire activity
(Gibson et al 2018), it is unclear if permafrost will re-aggrade in permafrost peatlands.
1.4 Permafrost change: climatic, ecological and social consequences
Permafrost thaw can cause a cascade of effects that affect both the ecological and
social components of northern ecosystems. The permafrost zone contains large carbon
stocks that have the potential to release substantial quantities of carbon to the
atmosphere following thaw (Schuur et al 2009). Permafrost soils contain ∼1700
gigatonnes (Gt) of carbon in the form of frozen organic matter, nearly twice as much
carbon than is currently in the atmosphere (Tarnocai et al 2009). It is estimated that an
additional ~ 208 Pg of carbon could be released into the atmosphere due to thawing
permafrost by 2300 (Mcguire et al 2018). This is equivalent to 5.7± 4.0% of total
anthropogenic emissions for the Intergovernmental Panel on Climate Change (IPCC)
6
representative concentration pathway (RCP) 8.5 scenario and would increase global
temperatures by 7.8 ± 5.7% (Schaefer et al 2014).
The thawing of permafrost landscapes also leads to widespread land instability
and the conversion of forested landscapes into wetland (bogs or fens) or lakes (Zoltai
and Tarnocai 1974). Baltzer et al. (2014) showed that over a 33-year period, a total of
8.6 ± 0.7% of black spruce forest were converted into wetlands. Further, it is estimated
that nearly 75% of all lakes north of 45.5°N are located in permafrost landscapes, with a
cumulative area of >400 000 km2 and originated from thermokarst processes (Liu et al
2014). The changing of the landscape from a forested/vegetative landscape to an
aquatic environment will have may downstream impacts.
Permafrost thaw and resulting mobilization of organic matter also will impact
aquatic environments by modulating erosion, water flow paths, and water availability to
organisms. These hydrological changes include changes in soil moisture, groundwater
recharge, streamflow seasonality, flow paths, and the amount of water stored on and
beneath the land surface (Quinton and Marsh 1999). Changes in hydrology and soil
characteristics also affect water and runoff quality, as permafrost materials are
transported to the aquatic environment as particulate and dissolved organic carbon
(POC and DOC, respectively) (Tank et al 2016). When this permafrost-derived DOC
reaches surface waters it becomes subject to different rates of processing by microbes
and ultraviolet (UV) sunlight (bio- and photo-degradation, respectively), resulting in the
production of greenhouse gases that ultimately escape to the atmosphere (Raymond et
al 2013). Additionally, increased POC and DOC concentration can increase the rate of
mercury methylation (MeHg; (Branfireun and Roulet 2010).
The functioning of healthy permafrost environments is critical for indigenous
communities that have relied upon the land since time immemorial. The thawing of
permafrost presents a multitude of challenges to which northern communities adapt to.
In a climate that is projected to become warmer and wetter, northern infrastructure is
increasingly at risk and the annual costs of replacing or repairing damaged areas are
7
ever increasing. Up to seventy percent of the current infrastructure in the Arctic has a
high potential to be affected by thawing permafrost in the next 30 years (Melvin et al
2017, Yumashev et al 2019).
In addition to infrastructure, permafrost thaw is affecting travel routes that
community members use to access important harvesting grounds, which ultimately
contributes to food insecurities (Calmels et al 2015). As permafrost thaws, animals on
the land are impacted and it is becoming increasingly difficult for community members
to access the land using traditional routes. Permafrost thaw will affect food security in
terms of availability and accessibility, by reducing access to important areas for
harvesting country food, and changes to the terrain and the ecosystems that make up
these landscapes. Water quality may also be affected, impacting fishing, drinking water
quality, and potentially triggering changes to the stability of the community’s water
supply (Calmels et al. 2015, Brinkman et al. 2016).
1.5 Thesis Objectives
The objective of this thesis is to enhance the understanding of permafrost
environments as an integrated system that considers humans and communities as part
of the permafrost system. In Chapter 2, I was interesting in understanding if, and to
what extent, scientifically published research addresses the full continuum of permafrost
thaw impacts, from ecosystem processes to ecosystem services to human well-being.
Further, I mapped the location of synthesized permafrost thaw measurements in relation
to communities in North America as one way to explore the current prevalence of
community-based measurements. Knowledge, and calls to action for integrated
permafrost research, generated in Chapter 1 informs the direction for the subsequent
chapters in this thesis.
In Chapter 3, I apply the call for more interdisciplinary and community-based
work to a case study in interior Alaska that determines and quantifies the impacts of
8
permafrost thaw on land-users. Using a community-based approach that integrates both
top-down and bottom-up knowledge, we provide a thematic understanding of the
manner and extent to which permafrost thaw generates hazards for land-users. An
emergent challenge identified in chapter 2 is the need for permafrost vulnerability data
at a scale that is more relevant to community-level planning (as opposed to circumpolar
scale analyses). Therefore, in Chapter 4, I map the spatial distribution of vulnerable
permafrost thaw at a scale that is relevant to community adaptation planning. The
purpose of this chapter is to update permafrost peatland vulnerability maps at local
scales within the discontinuous permafrost zone of the Northwest Territories. Data
generated in Chapter 4 are subsequently used in Chapter 5 as well as several other
studies (not included in this thesis) to understand controls on landscape scale mercury
concentrations, caribou land use and body condition, and regional hydrological
connectivity.
Finally, in Chapter 5, to support community risk assessments to thawing
permafrost, I assess how the degree of thermokarst formation within permafrost
peatlands varies across a latitudinal (climatic) gradient (i.e., space-for-time
substitutions) to make inferences about how thaw will progress in a warming climate. I
determine the role of other topographical controls (such as elevation) on thermokarst
formation and its importance for identifying vulnerable permafrost at scales relevant to
communities. The findings of this chapter are discussed in light of community needs for
data and understanding at scales that are relevant to community planning and
adaptation.
1.6 Chapter Publications and Author Contributions
The four main research chapters were prepared for submission to, or are
published in, academic peer-reviewed journals. These submissions include multiple co-
authors which were involved in the development, research, and writing phases as
outlined below.
9
Chapter 2 is in review in Nature Climate Change (Gibson et al. in review) and was
co-authored by Merritt Turetsky and Todd Brinkman. All authors conceived of and
designed the study. C.G. conducted all synthesis work, data analysis, and wrote the
manuscript. All co-authors provided comments and feedback on the manuscript.
Chapter 3 is in review in Environmental Research Letters (Gibson et al. in review)
and was co-authored by Merritt Turetsky, Todd Brinkman, Helen Cold, and Dana
Brown. C.G, M.T., and T.B., designed the study. H.C. and D.B. provided data that was
used in the study. C.G. conducted statistical analysis and wrote the manuscript. All
authors provided comments and feedback on the manuscript.
Chapter 4 is published as an open report the NWT Geological Survey (Gibson et
al. 2020) and the data report for the dataset was co-authored by Merritt Turetsky, Steve
Kokelj, Peter Morse, Jennifer Baltzer, Tristan Gingras-Hill, and Jocelyn Kelly. C.G., M.T,
S.K., P.M., and T.G.H., conceived the study design and J.K. assisted in data collection.
C.G. wrote the data report, and all authors provided comments and feedback on the
report.
Chapter 5 is in review in Environmental Research Letters (Gibson et al. in review)
and was co-authored by Merritt Turetsky, Karl Cottenie, Jennifer Baltzer, Steve Kokelj,
Tristan Gingras-Hill and Laura Chasmer. C.G., M.T, J.B., S.K., and K.C conceived the
study design. T.G.H. provided GIS support and data. K.C. and L.C. provided advise and
guidance on statistical analyses. C.G. conduced all statistical analysis and wrote the
manuscript. All authors provided comments and feedback on the final manuscript.
1.7 References
Baltzer J L, Veness T, Chasmer L E, Sniderhan A E and Quinton W L 2014 Forests on thawing permafrost: fragmentation, edge effects, and net forest loss. Glob. Chang.
Biol. 20 824–34 Bekryaev R V., Polyakov I V. and Alexeev V A 2010 Role of polar amplification in long-
term surface air temperature variations and modern arctic warming J. Clim. 23
3888–906
10
Branfireun B A and Roulet N T 2010 Controls on the fate and transport of
methylmercury in a boreal headwater catchment, northwestern Ontario, Canada
Hydrol. Earth Syst. Sci. 6 785–94 Brinkman T J, Hansen W D, Chapin F S, Kofinas G, BurnSilver S and Rupp T S 2016
Arctic communities perceive climate impacts on access as a critical challenge to
availability of subsistence resources Clim. Change 139 413–27 Brown, R.J.E., and Pewe, T.L. 1973. Distribution of permafrost in North America and its relationship to the environment: A review, 1963–1973. Ottawa: National Research
Council Canada. Brown, J., Ferrians, O.J., Jr., Heginbottom, J.A., and Melnikov, E.S. 2002. Circum-Arctic
map of permafrost and ground ice conditions, Version 2. Boulder, Colorado:
National Snow and Ice Data Center. Burd K, Tank S E, Quinton W L, Olefeldt D, Dion N, Tanentzap A J and Spence C 2018
Seasonal shifts in export of DOC and nutrients from burned and unburned
peatland-rich catchments, Northwest Territories, Canada Hydrol. Earth Syst. Sci. 22 4455–72
Calmels F, Laurent C, Brown R, Pivot F and Ireland M 2015 How Permafrost Thaw May
Impact Food Security of Jean Marie River First Nation, NWT GeoQuebec 2015 Conf. Pap.
Chapin F S 2005 Role of Land-Surface Changes in Arctic Summer Warming, Science
(80). 310 Chasmer L, Hopkinson C and Quinton W 2010 Quantifying errors in discontinuous
permafrost plateau change from optical data, Northwest Territories, Canada: 1947-
2008 Can. J. Remote Sens. 36 S211–23 Connon R F, Quinton W L, Craig J R and Hayashi M 2014 Changing hydrologic
connectivity due to permafrost thaw in the lower Liard River valley, NWT, Canada
Hydrol. Process. 28 4163–78 Flannigan M, Cantin A S, De Groot W J, Wotton M, Newbery A and Gowman L M 2013
Global wildland fire season severity in the 21st century For. Ecol. Manage. 294
54–61
11
Gibson C M, Chasmer L E, Thompson D K, Quinton W L, Flannigan M D and Olefeldt D 2018 Wildfire as a major driver of recent permafrost thaw in boreal peatlands Nat. Commun. 9
Gignac L D, Vitt D H, Zoltai S C and Bayley S E 1991 Bryophyte Response Surfaces Along Climatic, Chemical, and Physical Gradients in Peatlands of Western Canada Nov. Hedwigia 93 29–45
Gordon J, Quinton W, Branfireun B A and Olefeldt D 2016 Mercury and methylmercury biogeochemistry in a thawing permafrost wetland complex, Northwest Territories, Canada Hydrol. Process. 30 3627–38
Government of the Northerwest Territories. 2018. 2030 NWT Climate Change Strategic Framework. Yellowknife, NWT
Islam M A and Macdonald S E 2004 Ecophysiological adaptations of black spruce
(Picea mariana) and tamarack (Larix laricina) seedlings to flooding Trees - Struct. Funct. 18 35–42
IPCC. Summary for Policymakers 2018. In: IPCC, 2019: Summary for Policymakers. In:
Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial environments.
Jones B M, Grosse G, Arp C D, Miller E, Liu L, Hayes D J and Larsen C F 2015 Recent Arctic tundra fire initiates widespread thermokarst development Sci. Rep. 5
Jorgenson M T, Romanovsky V, Harden J, Shur Y, O’Donnell J, Schuur E A G,
Kanevskiy M and Marchenko S 2010 Resilience and vulnerability of permafrost to climate change Can. J. For. Res. 40 1219–36
Jorgenson M T, Shur Y L and Pullman E R 2006 Abrupt increase in permafrost
degradation in Arctic Alaska Geophys. Res. Lett. 33 Kokelj S V and Jorgenson M T 2013 Advances in Thermokarst Research Permafr.
Periglac. Process. 24 108–19
Liu L, Schaefer K, Gusmeroli A, Grosse G, Jones B M, Zhang T, Parsekian A D and
Zebker H A 2014 Seasonal thaw settlement at drained thermokarst lake basins, Arctic Alaska Cryosphere 8 815–26
12
Mcguire A D, Lawrence D M, Koven C, Clein J S, Burke E and Chen G 2018 Dependence of the evolution of carbon dynamics in the northern permafrost region on the trajectory of climate change 115 3882–7
Melvin A M, Larsen P, Boehlert B, Neumann J E, Chinowsky P, Espinet X, Martinich J, Baumann M S, Rennels L, Bothner A, Nicolsky D J and Marchenko S S 2017 Climate change damages to Alaska public infrastructure and the economics of proactive adaptation Proc. Natl. Acad. Sci. 114 E122–31
Moffat N D, Lantz T C, Fraser R H and Olthof I 2016 Recent Vegetation Change (1980–
2013) in the Tundra Ecosystems of the Tuktoyaktuk Coastlands, NWT, Canada Arctic, Antarct. Alp. Res. 48 581–97
Morgenstern A, Grosse G, Guenther F, Fedorova I and Schirrmeister L 2011 Spatial
analyses of thermokarst lakes and basins in Yedoma landscapes of the Lena Delta Cryosphere 5 849–67
Nelson F E, Anisimov O A and I. S N 2001 Subsidence Risk From Thawing Permafrost
Nature 410 889
Nixon, F.M. 2000. Thaw-depth monitoring. In: The physical environment of the Mackenzie Valley, Northwest Territories: a baseline for the assessment of
environmental change. L.D. Dyke and G.R. Brooks, Eds. Geological Survey of
Canada, Natural Resources Canada, Bulletin 547, pp. 119-126. Nixon, F.M., C. Tarnocai, and L. Kutny. 2003. Long-term active layer monitoring:
Mackenzie Valley, northwest Canada. In: Proceedings of the Eight international
Conference on Permafrost (Vol 2)., M. Philips, S.M. Springman, and L.U. Arenson, Eds., A.A. Balkema, Swets & Zeitlinger, Lisse, The Netherlands, pp. 821-826.
Pewe T L 1983 Alpine Permafrost in the Contiguous United States: A Review Arct. Alp.
Res. 15 145–56 Quinton W L and Marsh P 1999 A Conceptual Framework for Runoff Generation in a
Permafrost Environment Hydrol. Process. 13 2563–81
Raymond P A, Hartmann J, Lauerwald R, Sobek S, McDonald C, Hoover M, Butman D,
Striegl R, Mayorga E, Humborg C, Kortelainen P, Dürr H, Meybeck M, Ciais P and Guth P 2013 Global carbon dioxide emissions from inland waters Nature 503 355–
9
13
Schaefer K, Lantuit H, Romanovsky V E, Schuur E A G and Witt R 2014 The impact of the permafrost carbon feedback on global climate Environ. Res. Lett. 9
Schuur E A G, Vogel J G, Crummer K G, Lee H, Sickman J O and Osterkamp T E 2009
The effect of permafrost thaw on old carbon release and net carbon exchange from tundra Nature 459 556–9
Screen J A and Simmonds I 2010 The central role of diminishing sea ice in recent Arctic
temperature amplification Nature 464 1334–7 Seppala M 1986 The Origin of Palsas Geogr. Ann. 68 141–7
Shur Y L and Jorgenson M T 2007 Patterns of permafrost formation and degradation in relation to climate and ecosystems Permafr. Periglac. Process. 18 7–19
Smith S L, M M Burgess, D Riseborough, and F M. Nixon (2005), Recent trends
from Canadian permafrost thermal monitoring network sites, Perm. Per. Proc. 16, 19–30.
Sniderhan A E and Baltzer J L 2016 Growth dynamics of black spruce (Picea mariana)
in a rapidly thawing discontinuous permafrost peatland J. Geophys. Res. Biogeosciences 121 2988–3000
Suzanne E T, Robert G S, James W M and Steven V K 2016 Multi-decadal increases in
dissolved organic carbon and alkalinity flux from the Mackenzie drainage basin to the Arctic Ocean Environ. Res. Lett. 11 Article number 054015
Tank S E, Striegl R G, McClelland J W and Kokelj S V 2016 Multi-decadal increases in
dissolved organic carbon and alkalinity flux from the Mackenzie drainage basin to the Arctic Ocean Environ. Res. Lett. 11
Tarnocai C, Canadell J G, Schuur E A G, Kuhry P, Mazhitova G and Zimov S 2009 Soil
organic carbon pools in the northern circumpolar permafrost region Global Biogeochem. Cycles 23 1–11
Viereck L A, Werdin-pfisterer N R and Adams P C 2008 Effect of Wildfire and Fireline
Construction on the Annual Depth of Thaw in a Black Spruce Permafrost Forest in Interior Alaska : A 36-Year Record of Recovery Ninth Int. Conf. Permafr. 1845–50
Walker X J, Baltzer J L, Cumming S G, Day N J, Johnstone J F, Rogers B M, Solvik K,
Turetsky M R and Mack M C 2018 Soil organic layer combustion in boreal black
14
spruce and jack pine stands of the Northwest Territories, Canada Int. J. Wildl. Fire 27 125–34
Whitman E, Parisien M A, Thompson D K, Hall R J, Skakun R S and Flannigan M D
2018 Variability and drivers of burn severity in the northwestern Canadian boreal forest: Ecosphere 9 e02128
Yoshikawa K, Bolton W R, Romanovsky V E, Fukuda M and Hinzman L D 2002 Impacts
of wildfire on the permafrost in the boreal forests of Interior Alaska J. Geophys. Res. 108
Yumashev D, Hope C, Schaefer K, Riemann-Campe K, Iglesias-Suarez F, Jafarov E,
Burke E J, Young P J, Elshorbany Y and Whiteman G 2019 Climate policy implications of nonlinear decline of Arctic land permafrost and other cryosphere elements Nat. Commun. 10 1900
Zoltai S C 1993 Cyclic Development of Permafrost in the Peatlands of Northwestern Canada Arct. Alp. Res. 25 240–6
Zoltai S C and Tarnocai C 1974 Perennially Frozen Peatlands in the Western Arctic and
Subarctic of Canada Can. J. Earth Sci. 12 28–43 Zuckerman, B & D. Jefferson 1996. Human Population and the Environmental Crisis.
Jones & Bartlett Learning. p. 42. ISBN 9780867209662.
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2 Adding social dimensions to our understanding of permafrost as an integrative system
2.1 Introduction
Polar amplification is causing northern regions to warm at three to four times the
rate of the global average1. This has triggered widespread permafrost thaw2 that is
causing diverse and interconnected consequences for northern communities3,4.
Permafrost is subsurface material that has remained frozen for two or more consecutive
years5. When permafrost thaws it can cause a number of changes within ecosystems,
including wetting or drying of the landscape due to changes in hydrology6,7, shifts in
vegetation communities8,9, differences in hydrological connectivity10, erosion of banks11,
draining of lakes12, and altered biogeochemical states13. These changes in turn affect
the services and societal benefits that northerners derive from permafrost environments
including reliable access to subsistence resources14, infrastructure integrity3,15, safety
while traveling on the land (Gibson et al. in review) and many more. With the rate of
permafrost thaw in the northern hemisphere already accelerating16–20 and the area of
permafrost expected to decline by 20 – 35% by the mid-21st century2, an increasingly
complex socio-ecological problem is likely to emerge.
There is an ongoing call for the integration of human dimensions into climate
change research to facilitate robust and effective policies, governance, and actions21,22.
Two prominent research frameworks that have emerged from this need include
ecosystem services23 and community-based research methodologies24,25. Ecosystem
services are generally defined as the goods and services that are of value to people and
that are provided wholly or in part by ecosystems23. They describe the relevance of
ecosystem functions for human wellbeing, and help inform decision-making by focusing
on the interrelation and dependencies between societal and natural processes23.
Community-based research methodologies involve collective, reflective and systematic
inquiry in which researchers and community stakeholders engage as equal partners in
all steps of the research process with the goals of educating, improving practice or
16
bringing about social change24. By being community-based, the framework is grounded
in the needs, issues, concerns, and goals of communities. Furthermore, this framework
enables direct and meaningful engagement with communities, and supports the co-
production of knowledge25. Given that permafrost thaw will directly and indirectly affect
communities, it is imperative that permafrost research integrates human dimensions,
both by considering ecosystem services while also employing community-based
approaches.
We develop a conceptual model of the impacts of thaw within an integrated
permafrost change system, which we define as one that implicitly includes human
dimensions. The core of the model represents the structures, functions, and processes
in an ecosystem (herein referred to as ecosystem processes). The outer core
represents the contribution of an ecosystem to human and societal well-being (herein
referred to as human well-being). Processes and human well-being are linked indirectly
via ‘ecosystem services’, the middle core. Generating knowledge using an integrated
permafrost change system that includes both ecological and social dimensions of
permafrost environments is critical for supporting science-informed decision making and
adaptation planning in a warming climate. Here we present a scoping review26 to
understand the nature, extent and range of current scientific knowledge on permafrost
thaw. Specifically, we are interested in understanding if, and to what extent, scientifically
published research addresses the full continuum of permafrost thaw impacts, from
ecosystem processes to ecosystem services to human well-being. Further, we mapped
the location of synthesized permafrost thaw measurements in relation to communities in
North America as one way to explore the current prevalence of community-based
measurements.
2.2 Results and Discussion
We identified 34 broad impacts of permafrost thaw to incorporate in a conceptual
model of the impacts of permafrost thaw. This represents the integrated permafrost
change system. Each impact was classified as either an ‘ecosystem process’,
17
‘ecosystem service’ or ‘human well-being’ (Figure 2.1). Each of these thaw-related
impacts include a great degree of complexity and nuance in and of themselves, with
entire scoping reviews able to be dedicated to each impact and the complexity therein.
However, the goal of our conceptual model was not to illustrate causal relationships or
feedbacks within or between certain impacts, but rather to demonstrate that this is a
highly coupled system with strong links between the core (ecosystem processes) and
the edges (human well-being). Importantly, this model emphasizes that the impacts of
permafrost thaw are part of a causal web27 and that the impacts of thaw will extend
beyond one disciplinary boundary.
18
Figure 2.1: Conceptual model of the impacts of permafrost thaw, classified as processes, services, or societal well-being. This represents an integrative permafrost change system that views the impacts of thaw across all these levels.
The scoping review yielded 387 articles for data analysis and charting (Figure
S1, Table S1). Our screening largely separated articles addressing a driver of
permafrost geophysical conditions versus articles addressing an outcome or ‘impact’ of
thawed permafrost. Our study focuses only on the latter. During the literature search,
we did not apply any chaining or snowball searching28 as we wanted to replicate the
actions of a community or decision maker searching out information to inform policy and
planning related to thawing permafrost. Given this approach, it is unlikely that all the
permafrost thaw-related papers were captured with the search strings used
(Supplemental 2.1). Search efforts and capturing of all relevant literature may also have
been impacted by number of terms that can be used to describe permafrost thaw (ex.
Thermokarst, subsistence, active layer thickening, erosion, thaw slump, hillslopes,
collapse scar, detachment/active layer failure, drunken forest, pingo, sinkhole,
retrogressive slide/thaw slump).
There has been an approximate 10-fold increase in the number of publications
between 2005 and 2018 addressing impacts of permafrost thaw. Despite this increase
in scholarship, there has been no consistent change in the balance of research on
between processes, services, and benefits (Figure 2.2). Collectively, 93% of published
permafrost research addressed ecosystem processes, 6% ecosystem services, and 2%
addressed human well-being. Research efforts were largely dominated by work in North
America, with nearly 70% of identified studies being conducted in Canada and Alaska
(Figure 2.3a). Canada and the Alaska, the countries affiliated with the most published
work, had 92% and 95% of permafrost research focused on ecosystem processes
respectively (Figure 3b). Countries with fewer studies tended to be more balanced. Half
of the permafrost research in Greenland and Iceland focused on ecosystem services.
The only permafrost studies that fell into the human-wellbeing category were conducted
in Russia and focused on economic well-being, food security, and human health.
19
Figure 2.2: Number of permafrost thaw-related publications per year, grouped by publication type as it relates to ecosystem process (red), services (orange), and human well-being (blue).
Figure 2.3: A) Proportion of permafrost thaw studies by country. B) Of the studies
located within each county, the proportion that focused on ecosystem process, ecosystem service, and human wellbeing. Ecosystem process work dominated nearly all countries, with the percentage of process-based work shown in the circle.
20
Process-based work was heavily dominated by terrestrial and aquatic carbon
cycling (46% of the processed-based studies), water chemistry (8% of the literature),
and microbial communities (8%, Table S2.2). Though not specifically measured as part
of this study, many processed-based work and carbon-related studies did bring together
methods from multiple disciplines. For example, studies examined carbon cycling and
climate services in the context of thaw-induced changes to plant communities, nutrient
cycling or microbial composition. Such efforts are a good start at exploring linkages
within the inner core of our conceptual model and help to push towards a multi-
disciplinary understanding of permafrost change. Next, we must expand this to include
studies addressing linkages with the outer core of our permafrost thaw-systems model
(Figure 2.1). Pushing outwards will require a greater degree of commitment to
interdisciplinarity that undoubtably cannot be met well by a single researcher or single
research group. More likely, it will require multiple and diverse groups with broad areas
of expertise beyond just the natural sciences. To support these types of collaborations,
academic structures and funding agencies must also transcend disciplinary boundaries
to reward meaningful collaboration and interdisciplinary research and training.
If, as a research community, we want to move to a more integrated
understanding of the permafrost change we must place equal emphasis and importance
on the ‘social’ part of the integrated permafrost change system and the humans that are
being affected by permafrost thaw. This simply is not possible if permafrost research
continues to take an “out of sight, out of mind”, and a ‘research despite communities’
approach. To illustrate this concept, we extracted study locations from the published
permafrost-thaw studies from Canada and Alaska in our database, and then mapped
them in relation to the location of communities (Figure 2.4). More than 75% of
communities do not have permafrost-thaw related measurements located within a 75km
radius, representing the area where most subsistence activities occurs for
communities29. This suggests that many communities are either reliant upon regional
21
permafrost trends, or simply cannot consider permafrost change and impacts as part of
their community planning.
Figure 2.4: Permafrost-thaw measurement locations were extracted from studies
located within Canada and Alaska (black dots). A heat map is then applied to identify areas of high and low densities of permafrost measurements. Emphasis is placed on the relative colours for density, as opposed to shape and size as the map is projected in Mercator Auxiliary Sphere causing distortions to the shape of the heat maps. Green
areas represent areas of higher permafrost measurement concentrations, while red represents fewer. Communities located within the permafrost zone and shown (blue triangle)30. Just over 75% of communities within the permafrost zone lack permafrost measurements within 75 km of them.
We found that many papers discussed the broader implications of their findings
in the context of impacts to communities while discussing their research findings. Yet,
given that so few studies reported engagement with communities in their methods or
overlapped in space with communities, we conclude that the majority of permafrost thaw
research currently is conducted in a community-absent way. A key step towards
understanding permafrost as an integrated system and bridging the gaps between
ecosystem process and human well-being is for permafrost researchers to focus on the
22
co-location and co-production of research with northern communities. This can lead to
tangible benefits to the research itself including incorporation of multiple ways of
knowing and inclusion of local knowledge and observations31. However, engagement
must be done in a way that recognizes a community’s right to self determination and
actively seeks to elevate and build capacity within communities31. This can only be
accomplished through a commitment to long-term and respectful relationships. This can
be a daunting task for new and established researchers, especially those who are not
trained in working with Indigenous peoples and interacting with Indigenous knowledge
systems32. Permafrost researchers should seek to identify mentors and collaborators
who have an established track record of community engagement. Researchers also
must be committed to establishing relationships and receiving feedback on what is the
best form of engagement and communication. In preparation, permafrost researchers
should educate themselves and colleagues on Indigenous history and rights to provide
a stronger understanding of socio-political landscape around their research sites33.
Community-engaged permafrost research is also going to require a strong
commitment to knowledge translation and dissemination. The publishing of technical,
often indigestible, scientific journals articles in paywalled journals can create unwanted
power dynamics and reinforces the notion that the only people who benefit from
permafrost research are researchers themselves. To ensure meaningful uptake of
permafrost knowledge, open access publications and a commitment to knowledge
translation must become the standard. This must be supported by policy changes by
institutions and funding agencies to penalize predatory journals34 and dismantle barriers
to open-access publishing35,36. Moreover, permafrost researchers must commit to
creating time, space and resources to working with or employing professional science
communicators to make research summaries that are accessible, contextualized, and
meaningful for end users. Creative mediums for knowledge dissemination such as
social media, videos, and podcasts should be explored to enhance uptake by non-
scientific communities. Funding bodies and university review boards must support and
23
create opportunities for diverse forms of science dissemination, recognizing that journal
publications are not the only metric and may not be the preferred metric of scientific
impact.
We make the following high-level recommendations as a call to action to our
fellow permafrost researchers. Our recommendations are aimed at advancing the state
of knowledge but also to ensure that our efforts more effectively support the people and
communities who are at the forefront of permafrost change. We first outline four
overarching guiding principles.
1. Shift in disciplinary practices to focus on interdisciplinary collaborations and cross-scale collaborations that push beyond ecosystem processes to focus on enhanced understanding of ecosystem services and human-welling by merging information collected at various scales (Gibson et al. 2020) in
permafrost landscapes. 2. Commitment to knowledge co-production, and research co-location, through
relationships built upon trust and respect that views communities as part of the research process, not just end-users.
3. Engagement in diverse, and open, forms of science communication to enable knowledge sharing and dissemination beyond the permafrost research community to end-users.
4. Realignment of funding programs to support and encourage interdisciplinary
research and community engagement.
In order to realize these principles, we provide examples of actions that can be taken by
members of the permafrost research community to move us towards a more integrated
understanding of permafrost change (Table 1).
Table 2.1: Examples of actions that can be taken by various actors within the permafrost research community in response to our call-to-action.
Actor Potential Actions
Funding Agencies
- Track and follow up on commitments made regarding community engagement and knowledge co-production
- Enhance funding opportunities for interdisciplinary research programs
24
- Provide funding boosts to research groups who
cultivate long-term relationships with communities and conduct this research ethically
- Support (both financially and for timeframes of grants)
for trust building and community engagement - Support for diverse initiatives that include but are not
limited to capacity building in the north and directly funding communities, not researchers.
- Provide funding to communities to lead their own research programs,
Universities
- Support data sharing platforms that are tied to
communities and community access while respecting issues related to data sovereignty
- Integrate new metrics into the promotion and tenure
process that rewards bridging science with community and policy.
- Ensure that tenure and promotion processes
recognize and value relationship building with communities
- Develop education and training opportunities about
indigenous histories, knowledge systems, and worldviews
- Enhance support and training for interdisciplinary
research programs by PIs and students
Principal Investigators
- Create more diversified project teams with
experienced researchers who have years of experience working with northern communities and developing relationships
- Two-way communication with communities to identify priority research questions and areas to help identify locations for study sites
- Develop allocation of funds for the development of outreach, training, and educational program that support multigeneration including youth
- Dedicate time and/or resources to proper dissemination of findings to decision/policy makers through proper channels (i.e., closing the loop)
- Engage in anti-colonial work that supports reconciliation.
- Complete training and education on indigenous
histories, knowledge systems, and cross-cultural communication
25
-
Students
- Complete training and education on indigenous
histories, knowledge systems, and cross-cultural communication
- Consider key words to ensure uptake of information
by target audiences in search engines and databases - Develop projects that include northern capacity
building and/or engagement as key deliverables or outcomes
2.3 Conclusion
While there are many barriers to understanding permafrost change as part of an
integrated system including funding models, academic incentive structures, and early-
career training37, it is crucial that researchers within the permafrost community work to
overcome these barriers and view their work as part of a integrated permafrost change
system. This study highlights the importance of viewing the permafrost environment
through an integrated lens that recognizes the impacts of permafrost thaw on
ecosystem processes, ecosystem services, and human well-being. Currently over 93%
of permafrost change related literature focuses on ecosystems process. Moreover,
more than 75% of northern North American communities lack permafrost change
related data within 75 km of them. This lack of overlap in space with communities and
very limited research bridging the gap between ecosystems processes and human well-
being suggests that many northern communities are likely highly reliant on
generalizations about the impact of permafrost thaw, or may not be considering the
impacts at as part of their land management planning.
By taking an integrated approach to permafrost research, it will provide us with
new insights into how our disciplinary efforts are aligned with others. It will allow us to
identify new and emerging complex problems posed by thawing permafrost and will
allow researchers to better articulate the complexities of permafrost change. Finally, in
identifying tangible actions that can be taken by all members of the permafrost
community, from funders to senior investigators, to graduate students it is our belief that
26
together the permafrost research community can tangibly move towards a more
integrated approach to permafrost change research. By advancing interdisciplinary and
community-based research methodologies we may gain a more integrated and holistic
of permafrost change, which is required in order to mobilize action to support northern
communities and those on the frontlines of climate change.
2.4 Methods
2.4.1 Review and assessment of the current state of knowledge on an integrated
permafrost system
A scoping review approach was used as it provides a rapid systematic method
for completing a comprehensive survey of the available knowledge37. Scoping reviews
are gaining popularity for their ability to address complex and and/or novel research and
have increasingly been used to address issues in wildfire, water security, hydrology,
and ecosystem service literature38–42. This approach provides a “descriptive account of
available research”26 and is generally used as a preliminary approach to identify
research gaps and future meta-analysis traditional reviews. The analysis of the
collected materials remains superficial and its quality is not assessed in depth. Given
this, a scoping review was selected for its ability to provide a preliminary review of
permafrost thaw related research and provide a high level, integrated understand of the
state of literature while identifying key gaps for future inquiry. We followed the five-step
methodology described by Arksey and O’Malley26 which includes a) identifying the
research question and developing search query; b) identifying relevant studies; c) study
selection; d) charting the data; and e) collating, summarizing, and reporting the results.
Our review focused on the impacts of permafrost thaw, including ecological,
social, economic, and political impacts. Literature that addresses the drivers and causes
of permafrost thaw were excluded. We constrained our review to scientific, peer
reviewed literature and did not include any grey literature (e.g. governmental reports,
27
industry reports) as we are interested in the state of scholarly research being
conducted.
2.4.2 Literature Searching, Screen, and Extraction
The search was conducted using three electronic databases: PubMed®, Science
Direct®, and Web of Science. These databases were selected based on their extensive
coverage of peer-reviewed literature in both the natural, health science, and social
science journals (Supplemental 2.2).
A two-step screening process was used to select relevant studies. The first step
conducted a primary screening to classify studies for inclusion or exclusion based on
title and abstract. The second step conducted a secondary screening to classify
remaining studies for inclusion or exclusion based on full text. Inclusion criterial included
location and language, date published and study topic/impacted addressed. Studies
need to be located with any of the 8 circumpolar nations (Canada, United States,
Russia, Greenland, Finland, Sweden, Norway, Iceland) where permafrost is prevalent
across the landscape and published in English. Studies from the Tibetan Plateau and
alpine environments were not included. Studies had to be published between 2005 to
2018. This timeframe uses the year 2005 as a limit to reflect the same year the
establishment of Sustainable Development Goals were established in which they
highlighted the importance of ecosystems services43. Additional screening criteria, and
main reasons for article exclusions are detailed in Supplemental 2.2.
A data extraction and charting tool was created to extract relevant details and
stored in a standardized format using the descriptive-analytical method of Arksey and
O’Malley (2005) 26, (see Supplemental 2.2). Studies were classified based on the
outcome of thaw (Figure 2.1) they assessed. In order to account for potential bias in the
sorting of articles, expert elicitation was used. Experts were defined as individuals who
have a extensive experience in permafrost environments through working, educating,
and publishing peer-reviewed scientific articles on permafrost related topics. A random
sample of selected (n=10) articles that passed primary screening was given to each
28
expert and they were asked to assign it into a topic category based on Figure 2.2.
Where differences in assigning occurred, an iterative process of consultation was
undertaken to reach consensus through the sharing and discussion of experts’
arguments for one category or the other.
2.4.3 Development of an integrated permafrost system conceptual model
During the data extraction phase, topics and themes of publication were
identified to form the permafrost thaw impacts within the integrated permafrost system
conceptual model. Additional impacts that did not emerge from the literature, but are
known to be impacted in a warming arctic and agreed by the authors, with many years
experience working in permafrost environments, could reasonably be impacted by
permafrost thaw, were added. These impacts were then classified accordingly as
processes, services, or human well-being. This categorized list of impacts was then
workshopped with members of the Permafrost Carbon Network44. This process was
iterative, with consensus achieved through the sharing and discussion of experts’
arguments for including or excluding certain topics.
2.4.4 Spatial distribution of permafrost related measurements
To determine the density of studies around communities (with more than 20
inhabitants), a case study with North America was used (i.e. studies at sites within
Canada and Alaska). Study locations were extracted from relevant literature and
converted in point vector locations in ArcGIS 10.6. For studies that did not provide
geographic coordinates for study sites (i.e. provided a map or a verbal description of the
location) locations were approximated. The point density tool in ArcGIS was used to
create a heat map for within the study area. Communities were assessed for their
nearness to permafrost measurements using the select by location function in ArcGIS.
29
2.5 References
1. Bekryaev, R. V., Polyakov, I. V. & Alexeev, V. A. Role of polar amplification in long-term surface air temperature variations and modern arctic warming. J. Clim. 23, 3888–3906 (2010).
2. IPCC 2018, I. Summary for Policymakers. In: IPCC, 2019: Summary for
Policymakers. In: Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food
security, and greenhouse gas fluxes in terrestr. doi:10.1016/j.oneear.2019.10.025. 3. Melvin, A. M. et al. Climate change damages to Alaska public infrastructure and
the economics of proactive adaptation. Proc. Natl. Acad. Sci. 114, E122–E131
(2017). 4. Andrews, T. D. et al. Permafrost Thaw and Aboriginal Cultural Landscapes in the
Gwich’in Region, Canada. APT Bull. J. Preserv. Technol. 47, 15–22 (2016).
5. (ACGR), A. C. on G. R. Canadian Glossary of Permafrost and Related Ground-ice
Terms, Technical Memorandum No. 142. (1988).
6. Quinton, W. L. & Marsh, P. A Conceptual Framework for Runoff Generation in a Permafrost Environment. Hydrol. Process. 13, 2563–2581 (1999).
7. Woo, M., Young, K. L. & Brown, L. High Arctic patchy wetlands: Hydrologic
variability and their sustainability. Phys. Geogr. 27, 297–307 (2006). 8. van der Kolk, H.-J., Heijmans, M. M. P. D., van Huissteden, J., Pullens, J. W. M. &
Berendse, F. Potential Arctic tundra vegetation shifts in response to changing
temperature, precipitation and permafrost thaw. BIOGEOSCIENCES 13, 6229–6245 (2016).
9. Johansson, T. et al. Decadal vegetation changes in a northern peatland,
greenhouse gas fluxes and net radiative forcing. Glob. Chang. Biol. 12, 2352–2369 (2006).
10. Quinton, W. L., Hayashi, M. & Chasmer, L. E. Permafrost-thaw-induced land-
cover change in the Canadian subarctic: implications for water resources. Hydrol. Process. 25, 152–158 (2011).
11. Lewkowicz, A. G. & Way, R. G. Extremes of summer climate trigger thousands of
thermokarst landslides in a High Arctic environment. Nat. Commun. 10, (2019).
30
12. Lantz, T. C. Vegetation Succession and Environmental Conditions following
Catastrophic Lake Drainage in Old Crow Flats, Yukon. ARCTIC 70, 177–189 (2017).
13. Schuur, E. A. G. et al. Climate change and the permafrost carbon feedback.
Nature 250, 217–227 (2015).
14. Brinkman, T. J. et al. Arctic communities perceive climate impacts on access as a critical challenge to availability of subsistence resources. Clim. Change 139, 413–427 (2016).
15. Hjort, J. et al. Degrading permafrost puts Arctic infrastructure at risk by mid-century. Nat. Commun. 9, (2018).
16. Gibson, C. M. et al. Wildfire as a major driver of recent permafrost thaw in boreal
peatlands. Nat. Commun. 9, (2018). 17. Lara, M. J. et al. Thermokarst rates intensify due to climate change and forest
fragmentation in an Alaskan boreal forest lowland. Glob. Chang. Biol. 22, 816–
829 (2016). 18. Baltzer, J. L., Veness, T., Chasmer, L. E., Sniderhan, A. E. & Quinton, W. L.
Forests on thawing permafrost: fragmentation, edge effects, and net forest loss.
Glob. Chang. Biol. 20, 824–834 (2014). 19. Chasmer, L., Hopkinson, C. & Quinton, W. Quantifying errors in discontinuous
permafrost plateau change from optical data, Northwest Territories, Canada:
1947-2008. Can. J. Remote Sens. 36, S211–S223 (2010). 20. Jorgenson, M. T. et al. Role of ground ice dynamics and ecological feedbacks in
recent ice wedge degradation and stabilization. J. Geophys. Res. Surf. 120,
2280–2297 (2015). 21. Bennett, E. M. et al. Bright spots: seeds of a good Anthropocene. Front. Ecol.
Environ. 14, 441–448 (2016).
22. Rissman, A. R. & Gillon, S. Where are Ecology and Biodiversity in Social–
Ecological Systems Research? A Review of Research Methods and Applied Recommendations. Conserv. Lett. 10, 86–93 (2017).
23. Assessment, M. E. Ecosystems and Human Well-being: Synthesis. (Island Press,
31
2005). doi:10.5822/978-1-61091-484-0_1. 24. Israel, B. A., Schulz, A. J., Parker, E. A. & Becker, A. B. Review of community-
based research: Assessing partnership approaches to improve public health.
Annu. Rev. Public Health 19, 173–202 (1998). 25. Minkler, M. Community-based research partnerships: Challenges and
opportunities. J. Urban Heal. 82, 3–12 (2005).
26. Arksey, H. & O’Malley, L. Ni. Int. J. Soc. Res. Methodol. Theory Pract. 8, 19–32
(2005).
27. Niemeijer, D. & De Groot, R. S. Framing environmental indicators: Moving from causal chains to causal networks. Environ. Dev. Sustain. 10, 89–106 (2008).
28. Ogilvie, D., Hamilton, V., Egan, M. & Petticrew, M. Systematic reviews of health
effects of social interventions: 1. Finding the evidence: How far should you go? J. Epidemiol. Community Health 59, 804–808 (2005).
29. Cold, H. S. et al. Assessing vulnerability of subsistence travel to effects of
environmental change in interior Alaska. Ecol. Soc. 25, (2020). 30. Canada, N. R. North America, National Atlas of Canada Reference Map Series.
(2000).
31. Reid, A. J. et al. “Two-Eyed Seeing”: An Indigenous framework to transform
fisheries research and management. Fish Fish. 1–19 (2020) doi:10.1111/faf.12516.
32. MacMillan, G. A. et al. Highlighting the potential of peer-led workshops in training
early-career researchers for conducting research with Indigenous communities. Facets 4, 275–292 (2019).
33. Wong, C., Ballegooyen, K., Ignace, L., Jane, M. & Johnson, G. Towards
reconciliation : 10 Calls to Action to natural scientists working in Canada. Face 769–783 (2020) doi:10.1139/facets-2020-0005.
34. Shen, C. & Björk, B. C. ‘Predatory’ open access: A longitudinal study of article
volumes and market characteristics. BMC Med. 13, 1–15 (2015).
35. Jahn, N. & Tullney, M. A study of institutional spending on open access publication fees in Germany. PeerJ 1–17 (2016) doi:10.7717/PEERJ.2323.
32
36. Fyfe, A. et al. Untangling Academic Publishing: A History Of The Relationship
Between Commercial Interests, Academic Prestige And The Circulation Of Research. https://zenodo.org/record/546100#.WgRImFVl9yw
doi:10.5281/zenodo.546100. 37. MacLeod, M. What makes interdisciplinarity difficult? Some consequences of
domain specificity in interdisciplinary practice. Synthese 195, 697–720 (2018).
38. Pham, M. T. et al. A scoping review of scoping reviews: Advancing the approach
and enhancing the consistency. Res. Synth. Methods 5, 371–385 (2014).
39. Bradford, L. E. A., Bharadwaj, L. A., Okpalauwaekwe, U. & Waldner, C. L. Drinking water quality in indigenous communities in Canada and health outcomes: A scoping review. Int. J. Circumpolar Health 75, 32336 (2016).
40. Hanna, D. E. L., Tomscha, S. A., Ouellet Dallaire, C. & Bennett, E. M. A review of riverine ecosystem service quantification: Research gaps and recommendations. J. Appl. Ecol. 55, 1299–1311 (2018).
41. Marshall, R. E., Levison, J. K., McBean, E. A., Brown, E. & Harper, S. L. Source water protection programs and Indigenous communities in Canada and the United States: A scoping review. J. Hydrol. 562, 358–370 (2018).
42. Robinne, F. N., Hallema, D. W., Bladon, K. D. & Buttle, J. M. Wildfire impacts on hydrologic ecosystem services in North American high-latitude forests: A scoping review. J. Hydrol. 581, 124360 (2020).
43. Vukomanovic, J. & Steelman, T. A Systematic Review of Relationships Between Mountain Wildfire and Ecosystem Services. Landsc. Ecol. 34, 1179–1194 (2019).
44. UN DESA. The Millennium Development Goals Report 2005. United Nations
http://unstats.un.org/unsd/mi/pdf/mdg book.pdf (2005) doi:10.1177/1757975909358250.
45. Permafrost Carbon Network. www.permafrostcarbon.org.
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3 Identifying increasing risks of hazards for northern land-users caused by permafrost thaw: integrating top-down and bottom-up research approaches
3.1 Abstract
Understanding the causes and consequences of environmental change is one of
the key challenges facing researchers today as both types of information are required
for decision making and adaptation planning. This need is particularly poignant in high
latitude regions where permafrost thaw is causing widespread changes to local
environments and the land-users who must adapt to changing conditions to sustain their
livelihoods. The inextricable link between humans and their environments is recognized
through socio-ecological systems research, yet many of these approaches employ top-
down solutions that can lead to local irrelevance and create tensions amongst groups.
We present and employ a framework for the integration of top-down and bottom-up
knowledge sources that provides an enriched and thematic understanding of how
permafrost thaw will affect northern land-users. Using geospatial modeling of permafrost
vulnerability with community-based data from nine rural communities in Alaska, we
show that permafrost thaw is a major driver of hazards for land-users and accounts for
one third to half of hazards reported by community participants. This study develops an
integrated permafrost-land-user system, providing a framework for thematic inquiry for
future studies that will add value to large-scale institutional efforts and locally-relevant
observations of environmental change.
3.2 Introduction
3.2.1 Knowledge Integration
Around the globe, communities are increasingly coping with changing
environmental conditions due to climate change (IPCC 2018). Identifying the causes
34
and consequences of these environmental changes is a research priority as this
information is needed by decision makers to help support adaptation planning in an
uncertain future. This need is particularly evident in northern regions where rapid
climate warming is causing widespread permafrost thaw (IPCC 2018). Given that
people and nature are inextricably linked, overcoming environmental challenges, such
as thawing permafrost, will inevitably require an integration of both social and ecological
sciences (Lui et al., 2007, Milner-Gulland 2012, Fischer et al., 2015).
Social-ecological systems (SES) research has been widely accepted and touted as
the direction research and funding agencies are headed (Chapin et al., 2016). Many
approaches to SES (see review by Guerrero et al., 2018) focus heavily on integration of
disciplines but do not require and incorporate insight from local communities, public
interest groups or non-scientist communities that may be affected by problems and
attempted solutions (Fischer et al., 2015, Turner et al., 2016). By linking top-down
expertise and sophisticated large-scale modeling and data capabilities with bottom-up
local knowledge of finer-scale change and adaptation histories, power, experience and
wisdom can be shared in a bidirectional way to enhance understanding and outcomes
(Figure 3.1). Here we use a case study from interior Alaska that couples top-down
modeling of permafrost vulnerability with bottom-up community derived data of
landscape hazard experiences by land-users.
35
Figure 3.1: Conceptual model of the attributes of top-down and bottom-up knowledge sources and the emergent properties from the integration of these two knowledge sources.
3.2.2 Permafrost as a integrated system
Around the globe, communities are increasingly coping with changing environmental
conditions due to climate change (IPCC 2018). Identifying the causes and
consequences of these environmental changes is a research priority as this information
is needed by decision makers to help support adaptation planning in an uncertain
future. This need is particularly evident in northern regions where rapid climate warming
is causing widespread permafrost thaw (IPCC 2018). Given that people and nature are
inextricably linked, overcoming environmental challenges, such as thawing permafrost,
will inevitably require an integration of both social and ecological sciences (Lui et al.,
2007, Milner-Gulland 2012, Fischer et al., 2015).
36
Social-ecological systems (SES) research has been widely accepted and touted as
the direction research and funding agencies are headed (Chapin et al., 2016). Many
approaches to SES (see review by Guerrero et al., 2018) focus heavily on integration of
disciplines but do not require and incorporate insight from local communities, public
interest groups or non-scientist communities that may be affected by problems and
attempted solutions (Fischer et al., 2015, Turner et al., 2016). By linking top-down
expertise and sophisticated large-scale modeling and data capabilities with bottom-up
local knowledge of finer-scale change and adaptation histories, power, experience and
wisdom can be shared in a bidirectional way to enhance understanding and outcomes
(Figure 1). Here we use a case study from interior Alaska that couples top-down
modeling of permafrost vulnerability with bottom-up community derived data of
landscape hazard experiences by land-users.
3.3 Methods
3.3.1 Study Region, community partnerships, and data collection.
The Yukon River basin of interior Alaska (Figure 3.2) is used to investigate whether
permafrost thaw impacts land-users (Supplemental 3.1). As part of a NASA ABoVE
project (ID # NNX15AT72A) an intensive year-long partnership was developed with nine
rural communities (Cold et al. 2020) that represent a range of social and ecological
conditions within the study area (Cold et al. 2020, Figure 3.2, Table 3.S1). The data
collected by the communities represents personal photo, written, and oral
documentation of experiences (i.e., bottom-up knowledge, Figure 3.1). All interviews
and participants gave their informed written consent to participate in this study in
accordance to the University of Alaska Fairbanks Human Institutional Review Board
(IRB # 700936). Only participants who consented to have their responses and data
points presented visually have been included in this study. Therefore, we will be
reporting statistics on all data collected, but only visually displaying the geospatial
37
datapoints and photos that have been approved by the participants to share with public
audiences (Figure 3.2).
The mean population size across the nine communities as of 2010/2011 was 553
462 people and are a mix of European descent and Native Alaskan (Koyukon,
Holikachuk, Deg Hit’an Athabascan, and Gwich’in). All partner communities practice a
subsistence lifestyle and use a series of roads, trails, and navigable waterways to
access subsistence resources. Travel along these routes consists of passenger
vehicles, snowmobiles, ATVs, and boats. The nine communities vary in their
connectivity to roads, and this is known to decrease dependence on subsistence
resources (Magdanz et al. 2016). Given this, we report results at both the regional level
(pooling all communities) and for road-connected and non-road-connected (remote)
communities. Tok, Delta Junction, and Healy are connected via a road network and
have greater access to commercial resources such as fuel and groceries, and the cost
of commercial goods is less compared to the remote communities (Goldsmith 2007) of
Nulato, Grayling, Holy Cross, Lake Minchumina, Beaver and Venetie.
Land-users that were actively participating in subsistence activities and had
experience and knowledge of the traditional harvest areas around their community
received a camera-equipped GPS. Using their camera, they collected photos and
spatial coordinates of any environmental condition that affected their travel and access
to a given area on the land, referred to herein as ‘hazard’ data (Supplemental 2). Land-
users then filled out a form about each photo that explained their interpretation of what
was pictured, how the conditions pictured influenced their travel or access, how frequent
this environmental condition was observed in other places around their community, and
to what extent the condition affected their travel safety. Eighteen individuals recorded
environmental conditions affecting their land use for a 12-month period from March
2016 to July 2017.
38
Figure 3.2: Yukon River basin study area outlined in black with nine partner communities. Hazard locations identified by land-users shown in green circles. Only a subset of the hazard locations (n=184/442) that have been approved for publication by
the land-users are shown. These are underlain with the Olefeldt et al. (2016) permafrost thaw probability data. Base map provided by Esri, DigitalGlobe, Geo eye (ArcGIS version 10.3).
3.3.2 Identifying permafrost-driven hazards from bottom-up knowledge sources
and determining how permafrost-driven hazards affected land-users and their safety
Land-users’ hazard data that were missing GPS coordinates or photos were
removed (n=34), resulting in a total of 479 hazard locations for subsequent analyses.
To determine if permafrost thaw directly generated hazards for land-users, expert
assessment was used to code the photos based on the likelihood that the hazard was
related to a permafrost thaw event (Supplemental 3.3).
39
To understand how permafrost-driven hazards affect land-user’s activities, access to
the land, and their safety we used the local participant’s description of the effect of each
observation on travel and access to resources. Quotations from the participant
narratives were used to provide important context relevant to the hazards and the
situations land-users faced. Descriptions were organized into three broad categories:
impacts to equipment (e.g. damage to a motor), access (e.g. the blockage of a trail),
and historical areas (e.g., previous subsistence harvest locations). For this ethnographic
data, only conditions from hazards that were ‘highly likely’ or ‘likely’ to be caused by
permafrost were reported, as other conditions could be caused by other forms of
environmental change.
3.3.3 Quantifying the extent of and potential for permafrost-driven hazards from
top-down knowledge sources
To quantify the extent to which permafrost thaw directly created hazards for land-
users we used descriptive and summary statistics for the number hazards ‘highly likely’
or ‘likely’ caused by permafrost thaw. Due to differences in the reporting frequency and
engagement by communities (Table S3.1), we reported on the proportion of permafrost
hazards from a given community type (i.e. road connected or non-road connected) or
region, as opposed to the raw number of all hazards observed.
To quantify the extent to which permafrost thaw may indirectly create hazards for
land-users we overlaid the hazard dataset onto thermokarst potential map (Olefeldt et
al., 2016). This dataset provides a spatial modeling framework to predict where
thermokarst landscapes are or could develop (i.e., top-down knowledge of Figure 3.1;
Supplemental 3.2). This dataset provides the most comprehensive and spatially explicit
estimate of thermokarst landscapes across the study region (herein referred to as
permafrost thaw potential). Permafrost thaw potential is defined as high, moderate, low,
or none. A spatial join was completed in ArcGIS (Version 10.6) to assign a permafrost
thaw potential to each hazard point. For this analysis, we assume that all hazards
40
located in high thaw vulnerability areas are either directly or indirectly caused by
permafrost thaw.
To understand how significant the potential for permafrost thaw to act as a driver of
hazard generation is, we first use the Olefeldt et al. (2016) dataset to calculate the area
of none, low, moderate, and high permafrost thaw probabilities within each community’s
resource harvesting range. We use the Brown et al. (in prep) dataset that provides a
modeled subsistence-use area for each community and assume that the availability of
the use area is equal among land-users from that community (Supplemental 4). A chi-
square test was then used to determine if the proportion of hazards in a given thaw
vulnerability class are greater than would be expected based on the areas of that
vulnerability class within their harvesting range. For example, a significant chi-square
statistic (α < 0.05) would indicate that when a land-user traverses a higher permafrost
thaw potential area, the chances of encountering a hazard are disproportionately higher
compared with traversing a lower thaw probability area.
3.4 Results
3.4.1 Identification of permafrost-driven hazards
Over the one-year period, 18 land-users from nine partner communities collected
GPS data associated with 479 hazard locations (Figure 3.2 and Figure 3.3), including a
total of 441 with GPS locations and photos. Using expert assessment of the photos and
descriptions collected by the land-users to determine if permafrost thaw generated
hazards for land-users, it was revealed that there were numerous instances (n=142/441
hazards) and ways in which permafrost thaw created hazards (Figure 3.3).
41
Figure 3.3: Example of hazards encountered by land-users while on the land that were ‘highly likely’ or ‘likely’ to be caused by permafrost thaw. A) Lake edge erosion encroaches on a travel route. The land-users will soon need to reroute the trail. B) Riverbank thaw increases river sediment load and trees dislodged into the river become
a hazard for motor boats. C) Above-zero soils in the winter cause changes to hydrology and inhibit freeze-up of snowmobile routes. D) and E) Thawing soils create muddy trails that impede ATV travel.
3.4.2 Determination of how permafrost-driven hazards affected land-users and their safety
The written and oral descriptions documented by land-users provided insight into
how permafrost-driven hazards affected land-user’s activities, access to the land, and
their safety. Land-users described how permafrost-driven hazards affected them in each
of the three broad categories of impacts:
Impacts to equipment
“[It] adds debris to the water. This can ruin your day, or your whole fishing
summer in fact ([boat] propeller, lower unit). Makes for tougher gathering and
fishing. Fills your wheel or net with stuff. Have to pull net and wheel” – 66.34N,
-147.59W
42
Impacts to access
“Debris in water makes boating more dangerous and makes it harder to dock
the boat to access the area” – 66.33N, -147.59W
Impacts to historical areas
“Changes navigable channels. Need to find new fishing spots. Trees falling on
you, rolling waves. Changes to historic fishing area for the first time” – 66.33N,
-147.59W.
Of the hazards that were ‘highly likely’ or ‘likely’ attributed to permafrost thaw
(n=157), land-users reported 61% had a strong or moderate effect on their safety. Land-
users reported that of the hazards located within high or moderate thaw probability area
(n=256), 68% had a strong or moderate effect on their safety. One common hazard that
was reported and had a strong effect on land-user safety was the impact of thaw and
subsidence on ATV trails. The conversion of solid ground to wet, muddy areas makes it
extremely difficult, time consuming, and potentially dangerous to traverse as ATVs can
tip over. This impacts travel routes as it does not support travel using any form of
motorized vehicle (e.g. truck, quad/ATV). When this occurred, land-users had to break
new trails to find alternate routes, seek out new harvesting areas or change the timing
of access to the resource (i.e. wait for drier or colder conditions). These hazards
increased the amount of time a land-user was out on the land and reduced harvesting
efficiency. Land-users described how permafrost thaw generated these conditions and
the impacts it might have on their safety:
“This causes great difficulty as new trails must be cut around washouts or
dangerous riding occurs” – 63.84N, -145.21W.
“Trail is very wet and muddy – got stuck several times, other years it has been
dry in September” – 64.12N, -141.89W
43
“Need to use ATV instead of vehicles, takes longer when you’re harvesting” –
67.03N, -146.48W
3.4.3 Quantification of the extent of and potential for permafrost-driven hazards
The frequency to which permafrost thaw directly created hazards for land-users
throughout the entire region (i.e. the frequency of ‘highly likely’ or ‘likely’ caused by
permafrost thaw) was 33% (n=153) across the entire region (Figure 4a). This frequency
varied greatly between road-connected and non road-connected communities. In
general, road-connected communities had a lower frequency of ‘highly likely’ or ‘likely’
compared to rural communities.
Figure 3.4: Proportion of hazards that were highly likely, likely, unlikely to be caused by permafrost thaw (including unknown) based on the land-user’s photos and descriptions, and expert determination of relation to permafrost thaw (a). The proportion of
subsistence use areas that is covered by each thaw vulnerability class based on the Olefeldt et al. (2016) dataset (b). Results are reported for all communities combined as well as for road-connected communities and remote communities.
44
The extent to which permafrost thaw both directly and indirectly created hazards
for land-users throughout the entire region (i.e. the proportion of hazards located in high
thaw vulnerability areas) was 52% (Figure 3.4b). For context, high thaw vulnerability
areas covered only 21% of the study region and 27% of the combined harvesting area
of each community (Table S2, Figure 3.4). In nearly all the remote communities, there
were more hazards located in higher thaw vulnerability areas than would be expected
based on the area of high thaw vulnerable permafrost in a community’s harvesting
range (Chi squared test, Table S3.2). The proportion of high thaw probability within
communities harvesting areas ranged from 2 – 61% (Table S3.2). Road-connected
communities had lower proportions of their harvesting ranges composed of high thaw
probability areas (mean SD = 3.6 1.5%) compared to remote communities (mean
SD = 45.5 12.8%) (Figure 3.5). This phenomenon was particularly evident in Beaver
(a non-road connected community) where all the hazards occurred in high thaw
probability area despite high thaw probability areas only occupying 51% of their
harvesting range. This phenomenon was more muted in road-connected communities
with a higher proportion of hazards occurring in low probability areas compared to no-
thaw probability areas (Chi squared test, Table S2), but with relatively few hazards
occurring in the limited moderate and high thaw probability areas.
45
Figure 3.5: Permafrost thaw probability in the modeled subsistence-use area for each community (Olefeldt et al. 2016; Brown et al. in prep). Subset of hazard locations that have been approved by land-users are shown. Base map provided by Esri, National Geographic, Geo eye (ArcGIS version 10.3).
46
3.5 Discussion
Through a partnership with nine rural communities in interior Alaska, we showed
that permafrost thaw is a major driver and accounts for 30 to 50 percent of all hazards
and potentially as great as 50% of hazards. The proportion of permafrost-driven
hazards is higher than what would be predicted based on the area of high thaw
vulnerable permafrost within a community’s harvesting range.
A common effect of permafrost thaw documented by land-users in this study was
the thawing/erosion of riverbanks. The hazards generated by this form of permafrost
thaw are of particular concern for rural communities that have few roads/trails and are
highly dependent upon rivers for access to the land (Cold et al. 2020). Additionally, as
riverbanks erode, traditional landing spots become inaccessible and river channel flow
and navigation becomes less predictable (Kokelj et al 2013; Walvoord et al., 2016). It is
important to note that in addition to these impacts, riverbank erosion will also create
ecological consequences that land-users will need to adapt to such as high sediment
and nutrient loading that may ultimately affect upper trophic level species (Chin et al.,
2016). Therefore, while not part of this study, it is evident that an understanding of the
cumulative effects of permafrost thaw for land-users and their subsistence resources is
needed.
Another common effect of permafrost thaw identified by land-users was ATV
trails becoming more muddy and ‘soggy’. This is likely due to the destabilization of the
permafrost and thaw settlement/subsidence below the trail that increases soil moisture
(Zoltai et al. 1993). This form of hazard was reported in a lower frequency than river-
associated hazards, potentially due to difference in the source or mechanism of the
permafrost thaw: gradual active layer deepening versus abrupt thermokarst formation.
Past studies have shown that when asked to report environmental conditions, land-
users are more likely to report instantaneous (abrupt) changes as opposed to sustained
(gradual) changes (Bender et al. 1984; Collins et al., 2011). Active layer thickening
occurs over decades, with only a few cm a year of thaw each year (Hinkel et al., 1995;
47
Camill et al., 2005). Comparatively, thermokarst formation can erode whole riverbanks
in a matter of years (Kaneviskiy et al. 2016; Payne et al. 2016). Given this, it could be
hypothesized that land-users are more likely to report hazards associated with abrupt
permafrost thaw than those associated with gradual active layer thickening. This is not
to say, however, that active layer thickening is not affecting land-users. Adaptation to
these sorts of landscape changes may be gradual and occurring over many years
causing it not to appear as a ‘hazard’. To gain a more holistic understanding of how
permafrost thaw affects land-users, semi-structured ethnographies are needed to
document how permafrost has changed in the region and to provide the critical context
on how traditional harvesting activities are being altered. These qualitative data may be
merged with quantitative analysis of past remote-sensing scenes (Brown et al. 2020) to
reveal patterns of change in human-environment interactions.
In addition to the safety hazards created by these conditions that the land-users
identified, there are also likely a number of unintended economic consequences. The
‘soggy’ conditions that are created during the non-frozen months when permafrost
thaws, or the debris that is dislodged due to riverbank thaw are known to challenge
access by any motorized vehicle. They create an impediment that forces people to
devote more time and effort to rerouting their travel path, switching their mode of
access, or abandoning the use of that travel segment.
Cold et al. (2020) showed that the rate of climate related travel hazards is higher
for remote communities. For permafrost-driven hazards, while we observed a similar
pattern, this is not conclusive, as road-connected communities had substantially less
high-thaw probability areas within their harvesting range. This is not surprising as major
roads, and subsequently communities on those roads, are unlikely to be built in areas
that have large areas of vulnerable permafrost. Given this, it is evident that, while the
impacts of permafrost thaw are widespread, they also vary by community, suggesting
that singular, regional wide, and top-down approaches to adaptation may not be
sufficient. Instead, local-level planning will be necessary.
48
3.6 Conclusion
This study is one of the first to connect the impacts of permafrost thaw to hazard
generation for land-users. Because land management cannot halt the thawing of
permafrost, adaptation to these changing conditions will be critical. In order to plan,
adapt to, and manage safety concerns related to permafrost thaw-driven hazards,
communities and governments will require decision support tools that can assess
permafrost thaw risk. As shown by this study, these risk assessments will be most
effective if they combine top-down knowledge of thaw vulnerable areas with bottom-up
knowledge of the consequences of this thaw. Here we show that permafrost is a major
driver of hazards for land-users and accounts for one third to half of all hazards land-
users face while on the land. These permafrost-driven hazards are diverse and can
range from damage to equipment, to affecting access to traditional subsistence areas,
to causing safety concerns for land-users. This integrated understanding of both the
quantitative and qualitative impacts of thaw is a unique emergent property of this study
and allows for an amplified understanding of the permafrost environment.
3.7 References
Anderson, D., Ford, J. D., & Way, R. G. (2018). The Impacts of Climate and Social Changes on Cloudberry (Bakeapple) Picking: a Case Study from Southeastern Labrador. Human Ecology, 46(6), 849–863. doi: 10.1007/s10745-018-0038-3
Andrews, T. D., Kokelj, S. V., MacKay, G., Buysse, J., Kritsch, I., Andre, A., and Lantz, T., (2016). Permafrost thaw and aboriginal cultural landscapes in the Gwich’in region, Canada, APT Bulletin, 47, 15–22
Andrews, T. D., MacKay, G., & Andrew, L. (2012). Archaeological investigations of alpine ice patches in the Selwyn Mountains, Northwest Territories, Canada. Arctic, 65, 1–21. doi: 10.14430/arctic4182
Arctic Climate Impact Assessment (ACIA). Arctic Climate Impact Assessment; Cambridge University Press: Cambridge, UK, 2005
49
Baltzer, J. L., Veness, T., Chasmer, L. E., Sniderhan, A. E., & Quinton, W. L. (2014). Forests on thawing permafrost: Fragmentation, edge effects, and net forest loss. Global Change Biology, 20(3), 824–834. doi: 10.1111/gcb.12349
Bender, E., Case, T., & Gilpin, M. (1984). Perturbation Experiments in Community Ecology: Theory and Practice Author. Ecology, 65(1), 1–13.
Berkes, F., & D. Jolly. (2001). Adapting to Climate Change : Social-Ecological
Resilience in a Canadian Western Arctic Community. Conservation Ecology 5(2). Biskaborn, B. K., Smith, S. L., Noetzli, J., Matthes, H., Vieira, G., Streletskiy, D. A., …
Lantuit, H. (2019). Permafrost is warming at a global scale. Nature
Communications, 10(1), 1–11. doi: 10.1038/s41467-018-08240-4 Brinkman, T. J., Hansen, W. D., Chapin, F. S., Kofinas, G., BurnSilver, S., & Rupp, T. S.
(2016). Arctic communities perceive climate impacts on access as a critical
challenge to availability of subsistence resources. Climatic Change, 139(3–4), 413–427. doi: 10.1007/s10584-016-1819-6
Brinkman, T. J., Kofinas, G., Hansen, W. D., Chapin, F. S. I., & Rupp, S. (2013). A new
framework to manage hunting: Why we should shift focus from abundance to availability. The Wildlife Professional, 38–43.
Brinkman, T., Maracle, K. B., Kelly, J., Vandyke, M., Firmin, A., & Springsteen, A.
(2014). Impact of fuel costs on high-latitude subsistence activities. Ecology and Society, 19(4). doi: 10.5751/ES-06861-190418
Brown, J., Ferrians, O.J., Jr., Heginbottom, J.A., and Melnikov, E.S. (2002). Circum-
Arctic map of permafrost and ground ice conditions, Version 2. Boulder, Colorado: National Snow and Ice Data Center
Brown, R.J.E., and Pew e, T.L. (1973). Distribution of permafrost in North America and
its relationship to the environment: A review, 1963–1973. Ottawa: National Research Council Canada
Brubaker, M. Y., Bell, J. N., Berner, J. E., Warren, J. A. (2011). Climate change health
assessment: a novel approach for Alaska Native communities. International Journal of Circumpolar Health, 70(3): 266-273.
Burnsilver, S., J. Magdanz, R. Stotts, M. Berman, & G. Kofinas. (2016). Are Mixed
Economies Persistent or Transitional? Evidence Using Social Networks from Arctic Alaska. American Anthropologist 118(1):121–129.
50
Camill, P. (2005). Permafrost thaw accelerates in boreal peatlands during late-20th
century climate warming. Climatic Change, 68(1–2), 135–152. doi: 10.1007/s10584-005-4785-y
Chapin, F. S., Knapp, C. N., Brinkman, T. J., Bronen, R., & Cochran, P. (2016).
Community-empowered adaptation for self-reliance. Current Opinion in Environmental Sustainability, 19, 67–75. doi: 10.1016/j.cosust.2015.12.008
Chapin, F. S., Trainor, S. F., Huntington, O., Lovecraft, A. L., Zavaleta, E., Natcher, D.
C., … Naylor, R. L. (2008). Increasing Wildfire in Alaska’s Boreal Forest: Pathways to Potential Solutions of a Wicked Problem. BioScience, 58(6), 531–540. doi:
10.1641/b580609 Chin, K. S., Lento, J., Culp, J. M., Lacelle, D., & Kokelj, S. V. (2016). Permafrost thaw
and intense thermokarst activity decreases abundance of stream benthic
macroinvertebrates. Global Change Biology, 22(8), 2715–2728. doi: 10.1111/gcb.13225
Clark, P. U., Shakun, J. D., Marcott, S. A., Mix, A. C., Eby, M., Kulp, S., … Plattner, G.
K. (2016). Consequences of twenty-first-century policy for multi-millennial climate and sea-level change. Nature Climate Change, 6(4), 360–369. doi: 10.1038/nclimate2923
Cold, H. S., Brinkman, T. J., Brown, C. L., Hollingsworth, T. N., Brown, D. R. N., & Heeringa, K. M. (2020). Assessing vulnerability of subsistence travel to effects of environmental change in interior Alaska. Ecology and Society, 25(1). doi: 10.5751/ES-11426-250120
Collins, S. L., Carpenter, S. R., Swinton, S. M., Orenstein, D. E., Childers, D. L.,
Gragson, T. L., … Whitmer, A. C. (2011). An integrated conceptual framework for long-term social-ecological research. Frontiers in Ecology and the Environment,
9(6), 351–357. doi: 10.1890/100068 Dixon, E. J., Callanan, M. E., Hafner, A., & Hare, P. G. (2014). The Emergence of
Glacial Archaeology. Journal of Glacial Archaeology, 1(0), 1–9. doi:
10.1558/jga.v1i1.1 Fall, J. A. 2012. Subsistence in Alaska: a year 2010 update. Division of Subsistence,
Alaska Department of Fish and Game, Anchorage, Alaska, USA.
51
Fienup-Riordan, A., Brown, C., & Braem, N. M. (2013). The value of ethnography in times of change: The story of Emmonak. Deep-Sea Research Part II: Topical Studies in Oceanography, 94, 301–311. doi: 10.1016/j.dsr2.2013.04.005
Fischer, J., Gardner, T. A., Bennett, E. M., Balvanera, P., Biggs, R., Carpenter, S., … Tenhunen, J. (2015). Advancing sustainability through mainstreaming a social-ecological systems perspective. Current Opinion in Environmental Sustainability, 14, 144–149. doi: 10.1016/j.cosust.2015.06.002
Flynn, M., Ford, J. D., Labbé, J., Schrott, L., & Tagalik, S. (2019). Evaluating the
effectiveness of hazard mapping as climate change adaptation for community planning in degrading permafrost terrain. Sustainability Science, 14(4), 1041–1056.
doi: 10.1007/s11625-018-0614-x Folke, C., Biggs, R., Norström, A. V., Reyers, B., & Rockström, J. (2016). Social-
ecological resilience and biosphere-based sustainability science. Ecology and
Society, 21(3). doi: 10.5751/ES-08748-210341 Ford, J. D., & Furgal, C. (2009). Foreword to the special issue: Climate change impacts,
adaptation and vulnerability in the Arctic. Polar Research, 28(1), 1–9. doi:
10.1111/j.1751-8369.2009.00103.x Ford, J. D., & Pearce, T. (2010). What we know, do not know, and need to know about
climate change vulnerability in the western Canadian Arctic: A systematic literature
review. Environmental Research Letters, 5(1). doi: 10.1088/1748-9326/5/1/014008 Ford, J. D., & Smit, B. (2004). A framework for assessing the vulnerability of
communities in the Canadian Arctic to risks associated with climate change. Arctic,
57(4), 389–400. doi: 10.14430/arctic516 Ford, J. D., Clark, D., Pearce, T., Berrang-Ford, L., Copland, L., Dawson, J., … Harper,
S. L. (2019). Changing access to ice, land and water in Arctic communities. Nature
Climate Change, 9(4), 335–339. doi: 10.1038/s41558-019-0435-7 Gibson, C. M., Chasmer, L. E., Thompson, D. K., Quinton, W. L., Flannigan, M. D., &
Olefeldt, D. (2018). Wildfire as a major driver of recent permafrost thaw in boreal
peatlands. Nature Communications, 9(1). doi: 10.1038/s41467-018-05457-1 Gill, H., & Lantz, T. (2014). A Community-Based Approach to Mapping Gwich’in
Observations of Environmental Changes in the Lower Peel River Watershed, NT.
Journal of Ethnobiology, 34(3), 294. doi: 10.2993/0278-0771-34.3.294
52
Goldsmith, S. (2007). The remote rural economy of Alaska, Anchorage Alaska, University of Anchorage
Guerrero, A. M., Bennett, N. J., Wilson, K. A., Carter, N., Gill, D., Mills, M., … Nuno, A.
(2018). Achieving the promise of integration in social-ecological research: A review and prospectus. Ecology and Society, 23(3). doi: 10.5751/ES-10232-230338
Hasbrouck, T. R., Brinkman, T. J., Stout, G., Trochim, E., & Kielland, K. (2020).
Quantifying effects of environmental factors on moose harvest in Interior Alaska. Wildlife Biology, (2). doi: 10.2981/wlb.00631
Hinkel, K. M., & Nicholas, J. R. (1995). Active layer thaw rate at a boreal forest site in
central Alaska, USA. Arctic and Alpine Research, 27(1), 72–80. doi: 10.2307/1552069
Hinzman, L. D., Bettez, N. D., Bolton, W. R., Chapin, F. S., Dyurgerov, M. B., Fastie, C.
L., … Yoshikawa, K. (2005). Evidence and implications of recent c limate change in Northern Alaska and other Arctic regions. Climatic Change, 72(3), 251–298. doi: 10.1007/s10584-005-5352-2
Huntington, H.P., Fox, S., Berkes, F., & Krupnik I (2005) The changing Arctic: indigenous perspectives. In: ACIA (ed) Arctic climate impact assessment. Cambridge University Press, Cambridge, p. 61–98
IPCC, 2018: Summary for Policymakers. In: Global warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and
efforts to eradicate poverty [V. Masson-Delmotte, P. Zhai, H. O. Portner, D. Roberts, J. Skea, P. R. Shukla, A. Pirani, W. Moufouma-Okia, C. Pean, R. Pidcock, S. Connors, J. B. R. Matthews, Y. Chen, X. Zhou, M. I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, T. Waterfield (eds.)]. World Meteorological Organization,
Geneva, Switzerland, 32 pp. Johnson, I., Brinkman, T., Britton, K., Kelly, J., Hundertmark, K., Lake, B., & Verbyla, D.
(2016). Quantifying Rural Hunter Access in Alaska. Human Dimensions of Wildlife,
21(3), 240–253. doi: 10.1080/10871209.2016.1137109 Johnson, J. S., Nobmann, E. D., Asay, E., & Lanier, A. P. (2009). Dietary intake of
Alaska Native people in two regions and implications for health: The Alaska Native
dietary and subsistence food assessment project. International Journal of Circumpolar Health, 68(2), 109–122. doi: 10.3402/ijch.v68i2.18320
53
Jorgenson, M. T., Racine, C. H., Walters, J. C., & Osterkamp, T. E. (2001). Permafrost
degradation and ecological changes associated with a warming climate in central Alaska. Climatic Change, 48(4), 551–579. doi: 10.1023/A:1005667424292
Jorgenson, M. T., Shur, Y. L., & Pullman, E. R. (2006). Abrupt increase in permafrost
degradation in Arctic Alaska. Geophysical Research Letters, 33(2), 2–5. doi: 10.1029/2005GL024960
Kanevskiy, M., Shur, Y., Strauss, J., Jorgenson, T., Fortier, D., Stephani, E., & Vasiliev,
A. (2016). Patterns and rates of riverbank erosion involving ice-rich permafrost (yedoma) in northern Alaska. Geomorphology, 253, 370–384. doi:
10.1016/j.geomorph.2015.10.023 Kokelj, S. V., & Jorgenson, M. T. (2013). Advances in thermokarst research. Permafrost
and Periglacial Processes, 24(2), 108–119. doi: 10.1002/ppp.1779
Laidler, G. J., Hirose, T., Kapfer, M., Ikummaq, T., Joamie, E., & Elee, P. (2011).
Evaluating the Floe Edge Service: How well can SAR imagery address Inuit community concerns around sea ice change and travel safety? Canadian
Geographer, 55(1), 91–107. doi: 10.1111/j.1541-0064.2010.00347.x Lambden, J., Receveur, O., & Kuhnlein, H. V. (2007). Traditional food attributes must be
included in studies of food security in the Canadian Arctic. International Journal of
Circumpolar Health, 66(4), 308–319. doi: 10.3402/ijch.v66i4.18272 Lantz, T. C., & Kokelj, S. V. (2008). Increasing rates of retrogressive thaw slump activity
in the Mackenzie Delta region, N.W.T., Canada. Geophysical Research Letters,
35(6), 1–5. doi: 10.1029/2007GL032433 Lara, M. J., Genet, H., Mcguire, A. D., Euskirchen, E. S., Zhang, Y., Brown, D. R. N., …
Bolton, W. R. (2016). Thermokarst rates intensify due to climate change and forest
fragmentation in an Alaskan boreal forest lowland. Global Change Biology, 22(2), 816–829. doi: 10.1111/gcb.13124
Lewkowicz, A. G., & Way, R. G. (2019). Extremes of summer climate trigger thousands
of thermokarst landslides in a High Arctic environment. Nature Communications, 10(1), 1–11. doi: 10.1038/s41467-019-09314-7
Leorna, S., Brinkman, T., McIntyre, J., Wendling, B., & Prugh, L. (2020). Association
between weather and Dall’s sheep Ovis dalli dalli harvest success in Alaska. Wildlife Biology, 2020(2). doi: 10.2981/wlb.00660
54
Liu, J., Dietz, T., Carpenter, S. R., Alberti, M., Folke, C., Moran, E., … Taylor, W. W.
(2007). Complexity of coupled human and natural systems. Science, 317(5844), 1513–1516. doi: 10.1126/science.1144004
Magdanz J.S., et al. (2009) Patterns and trends in subsistence salmon harvests, Norton
Sound–Port Clarence Area, Alaska 1994–2003. Pacific Salmon: Ecology and Management of Western Alaska’s Populations, eds Krueger C, Zimmerman C (Am
Fisheries Soc, Bethesda), Vol 70, pp 395–431 Maldonado, J. K., Shearer, C., Bronen, R., Peterson, K., & Lazrus, H. (2013). The
impact of climate change on tribal communities in the US: Displacement, relocation,
and human rights. Climatic Change, 120(3), 601–614. doi: 10.1007/s10584-013-0746-z
McDowell, G., Ford, J., & Jones, J. (2016). Community-level climate change
vulnerability research: Trends, progress, and future directions. Environmental Research Letters, 11(3). doi: 10.1088/1748-9326/11/3/033001
Milner-Gulland, E. J. (2012). Interactions between human behaviour and ecological
systems. Philosophical Transactions of the Royal Society B: Biological Sciences, 367(1586), 270–278. doi: 10.1098/rstb.2011.0175
Moerlein, K. J., & Carothers, C. (2012). Total Environment of Change: Impacts of
Climate Change and Social Transitions on Subsistence Fisheries in Northwest Alaska. Ecology and Society, 17(1). doi: 10.5751/es-04543-170110
Noongwook, G., Huntington, H. P., & George, J. C. (2007). Traditional knowledge of the
bowhead whale (Balaena mysticetus) around St. Lawrence Island, Alaska. Arctic, 60(1), 47–54. doi: 10.14430/arctic264
Nuttall, M., Berkest, F., Forbes, B., Kofinas, G., Vlassova, T., & Wensel, G. (2005).
Hunting, herding, fishing, and gathering: Indigenous peoples and renewable resource use in the Arctic; in Arctic Climate Impacts Assessment; Cambrindge University Press, Cambridge, United Kingdon, p. 649-690
Olefeldt, D., Goswami, S., Grosse, G., Hayes, D., Hugelius, G., Kuhry, P., … Turetsky, M. R. (2016). Circumpolar distribution and carbon storage of thermokarst landscapes. Nature Communications, 7, 1–11. doi: 10.1038/ncomms13043
Osterkamp, T. E., & Romanovsky, V. E. (1999). Evidence for warming and thawing of discontinuous permafrost in Alaska. Permafrost and Periglacial Processes, 10(1),
55
17–37. doi: 10.1002/(SICI)1099-1530(199901/03)10:1<17::AID-PPP303>3.0.CO;2-4
Payne, C., Panda, S., & Prakash, A. (2018). Remote sensing of river erosion on the
Colville river, North Slope Alaska. Remote Sensing, 10(3). doi: 10.3390/rs10030397
Pearce, T., Ford, J. D., Caron, A., & Kudlak, B. P. (2012). Climate change adaptation
planning in remote, resource-dependent communities: An Arctic example. Regional Environmental Change, 12(4), 825–837. doi: 10.1007/s10113-012-0297-2
Pewe, T. L. (1983). Alpine Permafrost in the Contiguous United States: A Review. Arctic
and Alpine Research 15(2):145–156. Schuur, E. A. G., & Mack, M. C. (2018). Ecological Response to Permafrost Thaw and
Consequences for Local and Global Ecosystem Services. Annual Review of
Ecology, Evolution, and Systematics, 49(1), 279–301. doi: 10.1146/annurev-ecolsys-121415-032349
Schuur, E. A. G., Bockheim, J., Canadell, J. G., Euskirchen, E., Field, C. B.,
Goryachkin, S. V., … Zimov, S. A. (2008). Vulnerability of Permafrost Carbon to Climate Change: Implications for the Global Carbon Cycle. BioScience, 58(8), 701–714. doi: 10.1641/b580807
Schuur, E. A. G., Crummer, K. G., Vogel, J. G., & MacK, M. C. (2007). Plant species composition and productivity following permafrost thaw and thermokarst in Alaskan tundra. Ecosystems, 10(2), 280–292. doi: 10.1007/s10021-007-9024-0
Smith, J., B. Saylor, P. Easton, and D. Wiedman. (2009). Measurable benefits of traditional food customs in the lives of rural and urban Alaska Inupiaq elders. Alaska Journal of Anthropology 7(1):87-97.
Tank, S. E., Striegl, R. G., McClelland, J. W., & Kokelj, S. V. (2016). Multi-decadal increases in dissolved organic carbon and alkalinity flux from the Mackenzie drainage basin to the Arctic Ocean. Environmental Research Letters, 11(5). doi: 10.1088/1748-9326/11/5/054015
Tape, K. D., Christie, K., Carroll, G., & O’Donnell, J. A. (2016). Novel wildlife in the
Arctic: The influence of changing riparian ecosystems and shrub habitat expansion on snowshoe hares. Global Change Biology, 22(1), 208–219. doi:
10.1111/gcb.13058
56
Tengö, M., Brondizio, E. S., Elmqvist, T., Malmer, P., & Spierenburg, M. (2014). Connecting diverse knowledge systems for enhanced ecosystem governance: The multiple evidence base approach. Ambio, 43(5), 579–591. doi: 10.1007/s13280-014-0501-3
Turner, V. K., Benessaiah, K., Warren, S., & Iwaniec, D. (2015). Essential tensions in
interdisciplinary scholarship: navigating challenges in affect, epistemologies, and structure in environment–society research centers. Higher Education, 70(4), 649–
665. doi: 10.1007/s10734-015-9859-9 Van Lanen, J. M., C. Stevens, C. L. Brown, K. B. Maracle, and D. S. Koster. 2012.
Subsistence land mammal harvests and uses, Yukon Flats, Alaska: 2008-2010
harvest report and ethnographic update. Technical Paper No. 377. Division of Subsistence, Alaska Department of Fish and Game, Anchorage, Alaska, USA.
Vitt, D. H., Halsey, L. A., & Zoltai, S. C. (1994). The bog landforms of continental
western Canada in relation to climate and permafrost patterns. Arctic & Alpine Research, 26(1), 1–13. doi: 10.2307/1551870
Walvoord, M. A., & Kurylyk, B. L. (2016). Hydrologic Impacts of Thawing Permafrost-A
Review. Vadose Zone Journal, 15(6), vzj2016.01.0010. doi: 10.2136/vzj2016.01.0010
Washburn, A.L. (1980). Geocryology: A survey of periglacial processes and
environments. New York: Wiley Wolfe, R. J. (2000). Subsistence in Alaska: a year 2000 update. Division of
Subsistence, Alaska Department of Fish and Game, Anchorage, Alaska, USA.
Zoltai, S. C. (1993). Cyclic Development of Permafrost in the Peatlands of Northwestern
Canada. Arctic and Alpine Research 25(3):240–246.
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4 Thermokarst Mapping Collective: Protocol for organic permafrost terrain and preliminary inventory from the Taiga Plains test area, Northwest Territories
4.1 Abstract
The Northwest Territories Thermokarst Mapping Collective collaboratively
develops protocols to map permafrost landforms and evidence of thermokarst to create
inventories and assess permafrost terrain sensitivity for the Northwest Territories. This
report presents a protocol for mapping organic permafrost terrain in the sporadic and
discontinuous permafrost zone using Sentinel-2 satellite imagery, and an inventory of
the spatial distribution of organic permafrost terrain (permafrost peatlands) and related
thermokarst for a test area in the sporadic and discontinuous permafrost zone of the
Taiga Plains, Northwest Territories. A 322 340 km2 area was mapped using a gridded
classification approach with 3.75 km × 3.75 km grid cells (within the 15 km × 15 km grid
cells used by the Northwest Territories Thermokarst Collective). Of the 3.75 km × 3.75
km cells, 53% contained permafrost peatland complexes, and the degree of thermokarst
degradation decreased abruptly north of 64°N. These preliminary data precede the
completion of mapping all of the Northwest Territories including organic terrain in the
continuous permafrost zone.
4.2 Introduction
The thawing of ice‐rich permafrost (“thermokarst”) can reduce ground stability,
modify terrain, and reconfigure drainage patterns, affecting terrestrial and aquatic
ecosystems (Kokelj and Jorgenson 2013) and present challenges to northern
infrastructure and communities (Hjort et al. 2018). Identifying geomorphic terrain
features indicative of permafrost and thermokarst processes enables mapping and
prediction of thaw susceptible landscapes (Chasmer and Hopkinson 2017). Variations in
geology, topography, climate, and ecosystems yield a diversity of permafrost conditions
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and controls the response to thaw. However, there is no empirical or systematic broad-
scale dataset describes the variation in thaw sensitivity across the Northwest Territories
(NWT). In 2019, the NWT Thermokarst Mapping Collective was initiated to
collaboratively develop a set of methodologies to classify and map permafrost terrain
and thermokarst features using Sentinel-2 satellite imagery available for the entirety of
the NWT. This project implements a grid-based framework to map relevant features on
a uniform grid, thus allowing for standardized mapping across large regions.
Organic permafrost terrain is one of the four mapping themes (slopes and mass
wasting, hydrological features, periglacial features, and organic terrain) identified by the
Collective. The goal of the Organic Terrain Working Group is to determine the
distribution of permafrost peatland complexes in the NWT and to categorize the degree
to which organic terrain is affected by thermokarst collapse. A complex is defined by the
maximum extent of the current permafrost peat plateau and recently degraded areas
within it, Figure 1. This report reviews organic permafrost terrain features in
discontinuous permafrost, presents a rubric for identifying them on 2016-2017 Sentinel-
2 imagery, describes a protocol for mapping the distribution and state of organic
permafrost terrain, and presents a preliminary inventory for the Taiga Plains ecoregion
underlain by discontinuous permafrost. The preliminary data product in this report
precedes the completion of mapping for other ecoregions in the NWT that will use the
same rubric and semi-automative approach presented here.
4.3 Background
4.3.1 Permafrost and thermokarst
Permafrost, ground that remains at or below 0°C for two or more years (ACGR
1988), is the geological manifestation of climate. In northwestern Canada, the
distribution, thickness, thermal regime, and ice content of permafrost reflect the
geological legacy of the region and the influence of climatic variations and biophysical
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processes over the past hundreds to thousands of years (Williams and Smith 1989).
Current and past biophysical factors including topography, vegetation cover, snow
depth, soil type, and moisture conditions, all have an important influence on defining
spatial variation in local and regional permafrost conditions (Williams and Smith 1989;
Bonnaventure et al. 2012; Carpino et al. 2018). For example, seasonal variation in the
thermal properties of peat, insulating the ground in the summer and promoting cooling
in the winter, explains why permafrost can exist where mean annual air temperatures
exceed 2°C (Romanovsky and Osterkamp 1995; Burn 2004). As a result, permafrost is
increasingly restricted to peatlands/organic terrain with decreasing latitude (Brown
1967). At soil temperatures below 0 °C, nearly all the water is present as ground ice.
For boreal regions permafrost that is in fine-grained, frost-susceptible materials, it is
typically ice rich (Mackay 1972; Shur et al. 2005). Though related to temperature, the
most important determinant of ground ice content is the geomorphic setting, which
reflects soil physical properties, available moisture, and the process and duration of ice
formation (Mackay 1972).
Permafrost can thaw if climate change or other disturbances, such as a fire (e.g.,
Burn 1998; Gibson et al. 2018) or development (e.g., Hjort et al. 2018), alter surface
boundary conditions and cause the ground to warm. Degradation of ice-rich permafrost
leads to the consolidation of thawed materials and ground subsidence, which in flat
terrain may lead to ponding. Ponding has a warming effect on the ground, which is
typically compounded by the accumulation of a deeper snow cover in depressions
formed by subsidence. Together, ponding and the accumulation of snow produce a
feedback that promotes further thaw, e.g., Morse and Burn (2013) and O’Neill and Burn
(2017). Ground ice conditions influence the ecological response to thawing permafrost.
In particular, discontinuous permafrost has a high spatial variation of frozen and
unfrozen terrain, with variable ice content in permafrost-affected areas (Fortier et al.
2011). Near-surface permafrost thaw is anticipated to accelerate during the 21st century
(Koven et al. 2013), due to a projected ~2°C to 4°C increase in global mean surface
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temperature compounded by a high-latitude amplification factor of 2.2 to 2.4 (Collins et
al. 2013). This may cause permafrost to thaw entirely in parts of the discontinuous
permafrost zone (Zoltai 1993; Chasmer and Hopkinson 2017). Knowledge of permafrost
conditions and landscape variation concerning the nature and intensity of thermokarst is
critical to predicting landscape and ecosystem change trajectories. However, in the
NWT empirical information on permafrost distribution and thermokarst development
patterns are limited to regional or local scale studies. This mapping project aims to
address this information gap by mapping permafrost terrain and evidence of
thermokarst on a territorial scale.
4.3.2 Organic permafrost terrain and related thermokarst
The rates and magnitudes of organic permafrost terrain response to thaw are of
particular interest (e.g. Baltzer et al. 2014, Chasmer and Hopkinson 2016, Gibson et al.
2018) due to the vast amounts of stored carbon and feedbacks on carbon cycling and
global climate change (Schuur et al. 2008, Schuur and Abbott 2011). In permafrost
regions, peat plateaus, polygonal peat plateaus, and palsas (Figure 1) are good
indicators of permafrost, and their spatial extent varies based on physiography, climate
history, and ecosystem conditions (Zoltai and Tarnocai 1975).
Permafrost peatland complexes are characterized by flat areas of well-drained
peat, elevated above surrounding terrain due to the accumulation of organic material
and uplift of the terrain that resulted as permafrost aggraded into underlying fine-grained
sediments. These landscapes are distinct on air photographs and satellite imagery due
to the high reflectance of lichen covered surfaces and a heterogenous (open) canopy of
black spruce forest (Picea mariana). These landscapes are perforated with thermokarst
collapse scars and/or distinct internal lawns characterized by bogs, fens, and shallow
open water wetlands that are permafrost free (Zoltai and Tarnocai 1975, Zoltai 1993,
Figure 1a). Some peatland complexes are dissected by troughs that form above a
network of ice wedges, creating a polygonal pattern when viewed from above (Zoltai
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and Tarnocai 1975, Figure 1b). However, these polygonal peatland complexes do not
occur within the test area reported on here and will be described in more detail and
mapped in subsequent reports. This report only concerns permafrost peatlands that are
found within the test area and does not include all organic features that may be found
elsewhere within the NWT.
Figure 4.1: a) Example of permafrost peat plateau complex (61°14'6.79"N, 117°35'23.81"W) in World View 2 imagery. Peat plateaus (medium green with ‘salt and pepper’ texture) represent areas where the permafrost is intact, while fen and/or bog areas (light to golden brown with comparatively homogeneous texture) are those in which permafrost thaw (thermokarst) has occurred. b) Example of polygonal permafrost
peatland (68°1'41.97"N, 132°38'51.45"W) in continuous permafrost in World View 2 imagery. Peat plateaus (white due to lichen coverage) are crisscrossed with polygonal troughs.
Permafrost peatlands, by nature, exist in a state of dynamic equilibrium, undergoing
a cycle of permafrost aggradation, degradation, and re-aggradation over about 600-
years (Zoltai 1993). During the aggradation phase, the waterlogged conditions in bogs
are dominated by Sphagnum riparium. This highly productive moss rapidly accumulates
biomass, which over time raises the organic surface above the water table. As the
surface rises, surface moisture conditions become increasingly dry, and there is a
succession of moss species; Sphagnum riparium is replaced by Sphagnum
angustifolium, and then by Sphagnum fuscum (Zoltai 1993). At this stage, black spruce
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(Picea mariana) and lichen (Cladonia spp.) can establish. The surface organic material
is relatively dry in summer, which minimizes ground heating due to poor thermal
conductivity of dry moss combined with evapotranspiration. With wetting by autumn
precipitation, it enhances winter ground cooling due to the high thermal conductivity of
frozen saturated mosses. Given this, the surface organic layer promotes permafrost
formation and preservation (Nelson et al. 1985). This “thermal offset” enables
equilibrium or aggrading permafrost to exist at locations where the mean annual ground
surface temperatures are above 0°C (Burn and Smith 1988). Over time, the permafrost
table rises with the accumulation of organic matter, trapping pore water (~80% pore
space) in the organic matter as ice, creating a peat plateau with a frozen, icy core
(Zoltai 1993). Aggradation of permafrost into the underlying fine-grained mineral soils,
and concomitant ice enrichment by segregation, can contribute significantly to the
relative elevation of the peat plateau.
Permafrost degradation and thermokarst development are initiated by gradual (e.g.,
climate change, development of dilation cracks) and/or rapid (e.g., fire) events that
modify the ground thermal regime (Zoltai 1993). As thawing progresses, the plateau
subsides to the level of the surrounding water table, waterlogging and killing the black
spruce (Islam and Macdonald 2004; Baltzer et al. 2014). The trajectory of thermokarst
subsidence is a function, in part, of the ice content of the underlying mineral sediments.
As subsidence continues, the surface soil layer approaches the water table, and
Sphagnum fuscum is gradually replaced by Sphagnum angustifolium then by
Sphagnum riparium (Gignac et al. 1991; Zoltai 1993). If there is sufficient organic
accumulation in the thermokarst depression, the organic surface may again rise above
the water table, and permafrost may subsequently re-aggrade to complete the cycle
(Zoltai 1993). Currently, in the southern NWT, plateaus are thawing and developing
thermokarst between a rate of 0.26% and 0.34% per year at undisturbed sites
(Chasmer et al. 2010; Baltzer et al. 2014; Gibson et al. 2018), and thermokarst
development is three times faster in areas disturbed by fire (Gibson et al. 2018). Due to
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the cumulative impacts of warming and increasing disturbances such as fire activity
(Gibson et al. 2018) and the sparsity of information on the ice contents of underlying
sediments, it is unclear if it is possible for permafrost to re-aggrade in these permafrost
peatlands.
4.4 Taiga Plains Test Area
The sporadic and discontinuous permafrost zone of the Taiga Plains (excluding
Great Bear Lake and Great Slave Lake within) was selected as a test area for peat
plateau complex mapping (Figure 4.2). This region is characterized by a range of
permafrost conditions comprising about 21% of the study region and provides an
ecoregion-based mapping product. The test area comprises 22 922 grid cells measuring
3.75 km × 3.75 km, totaling 322 340 km2. This area is characterized by a subdued relief
and gently rolling plains and is underlain with horizontal beds of sedimentary rocks
consisting of limestone, shale, sandstone, and conglomerates. The present landscape
of the Taiga Plains is primarily a legacy of glaciation of the entire Mackenzie Valley until
about ~30 ka BP by the Laurentide Ice sheet, and subsequent impoundment of
meltwater to establish glacial lakes during deglaciation (Duk-Rodkin and Lemmen
2000). Most of the test area is within the influence of glacial Lake McConnell, which by
about 10 ka BP had become the second-largest Pleistocene lake in North America,
covering all of the modern Great Bear, Great Slave and Athabasca basins (Lemmen et
al. 1994). Sediment deposition accompanied inundation by glacial Lake McConnell
between about 12 700 and 9300 cal BP (Lemmen et al. 1994). This late-Quaternary
history has left a suite of fine-grained surficial deposits, most notably, large areas of
glaciofluvial and glaciolacustrine materials and extensive till plains that have yielded
extensive, poorly-drained landscapes conducive to organic accumulation and wetland
development. Consequently, the Taiga Plains is one of the major peatland regions of
Canada – nearly 40% of the study area is peatlands (Ecosystem Classification Group
2007). Peat accumulation in this area was initiated following deglaciation ~9000 years
ago (Loisel et al. 2014). Soil development in the Taiga Plains is strongly related to the
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climate and local moisture and drainage conditions, with peat depths varying between 2
m and 6 m. Permafrost aggradation began during the climate cooling after the Holocene
thermal maximum ~5000 years ago and became more widespread following further
cooling 1200 years ago (Pelletier et al. 2017).
Figure 4.2: Map of the Taiga Plains test area within the NWT (322 340 km2). The
bottom left inset shows the location of the study area relative to northern Canada.
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4.5 Methodology
4.5.1 Sentinel-2 satellite imagery, processing, and spatial extent
The NWT Thermokarst Mapping Collective is focused on map products derived
from an electronic mosaic of Sentinel-2 satellite imagery obtained for the Government of
Northwest Territories. The mosaic comprises Sentinel-2 images collected in July and
August of 2016 and 2017, to minimize snow and ice cover. Input images were selected
to minimize cloud cover, smoke, and haze. Processed Sentinel-2 imagery, provided by
Northwest Territories Centre for Geomatics, was produced under a contract issued
through a competitive process to Pacific Geomatics© (Victoria, BC). Sentinel-2 data are
10-m resolution, true-color composite (B04 (Red), B03 (Green), B02 (Blue)) and false-
colour composite (B08 (NIR), B04 (Red), B03 (Green)) Level 1C imagery, calibrated to
Top of Atmosphere Reflectance. The image data coverage extends outside of the NWT
to include the watershed areas of major transboundary rivers, including the Liard and
Peel watersheds, northward flowing rivers from the Yukon into the Mackenzie Delta and
Beaufort Sea, Victoria Island, mainland Nunavut west of longitude 112°W, and
northward-flowing rivers from Alberta or Saskatchewan into the NWT, excluding the
Peace and Athabasca watersheds (Figure 4.3). During mapping, the satellite imagery is
viewed at a scale between 1:20 000 and 1:30 000 and histogram stretches are applied
to the imagery as needed to enhance the contrast.
4.5.2 Area of interest and mapping grid
The general mapping scheme for the NWT thermokarst collective project is to
assess the presence or relative abundance of permafrost features defined within 15 km
× 15 km areas of interest (AOI). In this way, the entire NWT is categorized into
approximately 13 499 AOI tiles organized as rows and columns (Figure 4.3). For
inventorying other permafrost features as part of the mapping initiative (e.g., slope,
mass wasting, hydrological, and periglacial features) AOI tiles are subdivided into four
7.5 km × 7.5 km quartiles to facilitate characterization of feature density. Due to the high
66
variability in the distribution of organic permafrost terrain and difficulty in mapping
peatlands as “point” features and counts, the grid system is further sub divided into four
3.75 km × 3.75 km sub-quartile cells, producing 16 sub-grid cells per 15 km2 AOI
(Figure 4.4). The feature assessment includes an estimation of percent extent of
organic permafrost terrain within each sub-grid cell. Data in this report is reported at the
3.75 km × 3.75 km sub-quartile cells.
4.5.3 Identifying organic permafrost terrain and associated thermokarst features on Sentinel-2 imagery
Peatland permafrost complexes, including those with polygons, are good
indicators of permafrost within discontinuous permafrost (Zoltai and Tarnocai 1975;
Figure 4.1a). This report focuses on methodologies to identify and map organic
permafrost terrain within the discontinuous permafrost zone. Polygonal permafrost
peatlands will be addressed in a follow-up report for organic terrain in continuous
permafrost.
Recognizing that there is a cyclical collapse and re-establishment of peat plateaus
(Zoltai and Tarnocai 1975), it was assume that current thaw features of the complex
delineate the former peat plateau extent. The method developed herein produces areal
estimates of permafrost peatland complexes and a rough estimate of the degree to
which the peat plateau has degraded (thawed or undergone thermokarst). It is expected
that variation is captured at multiple scales across the NWT, as permafrost peatland
complexes vary significantly in the extent of thermokarst due to variation in underlying
geology, ground ice conditions, hydrology, ground temperatures, and climate. Rates of
peat plateau degradation are not determined as the methods do not include a temporal
component.
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Figure 4.3: The Thermokarst Collective study area comprises NWT and shared watershed boundaries. Grids represent 15 km × 15 km areas of interest (AOI).
68
Figure 4.4: Gridded mapping methodology and naming convention. The 15 km × 15 km
grid cells were subdivided into 7.5 km × 7.5 km grid cells and then again into 3.75 km × 3.75 km grid cells for mapping organic permafrost terrain.
4.5.4 Identifying peat plateau complexes and percent cover
Several characteristics distinguish peat plateau complexes from the surrounding
landscape in Sentinel-2 imagery. All complexes, whether burned/unburned or
forested/unforested, typically appear as non-uniform patches that vary in size from less
than one kilometre squared to several kilometres squared, with a varying degree of
thermokarst in the form of collapse scars (Figure 4.1a; Figure 4.5). In contrast,
surrounding landscape features such as fens appear as elongated networks, and
forested mineral terrain that are not part of a peatland complex should not show
thermokarst in the form of collapse scars. Furthermore, these terrains also show a
contrasting colour and texture to the organic deposits due to contrasting vegetation and
soil moisture conditions. Lakes that are adjacent to, or within, the peatland complex are
not considered to be part of the complex. Lakes are larger than thermokarst ponds and
typically appear black in true-colour composite Sentinel-2 imagery. Cloud cover was
69
generally less than 5% on the Sentinel-2 imagery. In the event of cloud cover, high-
resolution imagery from the ArcGIS basemap was used. Lakes and cloud cover are not
included in the sub-grid cell area estimate. Examples of percent cover are shown in
Figure 5.
The percent cover of the complex within the cell is visually estimated according
to the following bins: None (0%), Trace (0% – 2%), Low (3% – 25%), Medium (26% –
50%), High (51% – 75%), Very High (76% – 100%).
Figure 4.5: Figure 5. Examples of peat plateau complexes for the suite of mapped
attributes: spatial extent, vegetation cover, and fire history.
4.5.5 Forested versus unforested peat plateaus
In true colour composite Sentinel-2 images, peat plateaus and thermokarst areas
appear in a variety of colours and textures. Forested peat plateaus are light to medium
70
shades of green, grey, or blueish-green and have a speckled appearance due to the
presence of trees that contrast with the underlying lichen-dominated ground cover.
Thermokarst features within the forested complex are commonly light to dark in shade
and colours vary from reddish-orange, orange, pink, brown, yellow, and beige, and are
typically larger than those associated with unforested peat plateau complexes (Figure
4.6a). Unforested peat plateaus appear to be a relatively homogeneous white due to the
lichen-dominated ground cover, while thermokarst features are often black and small
relative to the peat plateau area (Figure 4.6b).
Figure 4.6: Example of a) a permafrost peatland complex (61°14'6.79"N, 117°35'23.81"W), and b) an unforested permafrost peatland complex (64°53'16.04"N, 126°34'54.18"W).
4.5.6 Fire History
Permafrost peatland complexes affected by wildfire display the same shape and
distribution patterns as unburned plateaus, but the colours and textures are different.
Recently burned permafrost peatland complexes are black to dark brown (Figure 4.7a),
while older burns are lighter grey to brown (Figure 4.7b). Comparing the colour of a
permafrost peatland complex against the surrounding landscape features and other
71
nearby peatland complexes can help determine whether it has recently burned.
Similarly, surrounding unburned peatlands can help to determine if the fire affected
peatland is forested or unforested. This method cannot distinguish permafrost peatland
complexes that have historically experienced fire and undergone succession (i.e., fire
occurred > 50 years ago), as there is often no evidence of older fire disturbance in
present-day remotely-sensed imagery. Cells were considered fire affected if more than
50% of the peatland complexes in the cells were affected by fire.
Figure 4.7: Example for a) recently burned permafrost peatland complex (60°40'44.13"N, 117°41'59.12"W) and b) a historically burned permafrost peatland (Fire year = 2008, 63°29'2.05"N, 120°34'32.51"W). Forested peat plateaus that burned
recently are brownish-green, brown to dark brown, or black, while unforested peat plateaus take on a grey colour.
4.5.7 Degree of thermokarst degradation
The degree of peatland degradation was assessed by examining the relative
proportion of collapse scar areas within the permafrost peatland complex. Degradation
is classified as low (0% – 33%), medium (34% – 66%), or high (67% – 100%).
Examples in Figure 4.8 were used to guide the assessment.
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Figure 4.8: The degree of degradation (thermokarst) is categorized into three categories a) high (67% – 100%, 60°42'25.86"N, 117°52'33.62"W), b) medium (34% – 66%,
63°15'51.34"N, 121°46'44.66"W), and c) low (0% – 33%, 65°19'26.83"N, 124°56'32.56"W).
4.5.8 Populating the dataset
Mapping was conducted within ArcGIS 10.6 using a layer consisting of the 3.75
km × 3.75 km sub-grid cells and a layer showing the Sentinel-2 satellite image mosaic
(2016/2017). The Sentinel-2 imagery has a pixel size of 10 m, and features were
mapped at a set scale of 1:24 000. This allows mappers to confidently identify organic
terrain areas and assess relative coverage within the grid cells. When necessary,
ArcGIS World Imagery was used to provide high-resolution interpretations of landscape
features or feature validation.
For mapping organic permafrost terrain features, a generalized attribution of
recognizable features within every 3.75 km × 3.75 km sub-grid cell of the AOI was used.
With the sub-grid cell under investigation centered on the screen, the mapper selects
the cell and then the attributes icon on the editor toolbar (once the attribute toolbar
appears it remains until closed). The mapper then fills in the editable areas of the
attribute table for the selected cell. To standardize the feature attribution (Table 4.1),
fields in the attribute table are populated with a set of predetermined drop-down menus.
73
Assuming most sub-grid cells will not have organic permafrost terrain features, and to
make data entry more efficient, the data table is populated with 0 (“Null/None”) if only
the mapper initials are filled in. Once a cell is finished and all attributes are assigned,
the border of the cell becomes red and the mapper moves to the next unassessed sub-
grid cell.
Table 4.1: Attributes and inputs for the sub-grid cell classification of peat plateau complexes.
Attribute Description
Peatland complex
area
None (0%), Neglibible (< 2%), Low (2% – 25%), Medium (26% –
50%), High (51% – 75%), and Very High (76% – 100%) This attribute is represented by the median of each of these bins
within the data frame. Vegetation type Null (no permafrost peatland in grid cell), Forested, and
Unforested.
Fire history Null (no permafrost peatland in grid cell), Burned, and Unburned (referring to the organic terrain area, considered unburned if fire did
not affect the peatland complex).
Degree of degradation
Null (no permafrost peatland in grid cell), Low, Medium, and High.
Mapper Initials
For each sub-grid cell, the mapper determines the percent area of the cell (not
the land area) containing a permafrost peatland complex and assigns descriptive
attributes according to vegetation type, fire history, and degree of degradation
(thermokarst). For quality control purposes, the initials of the mapper is also recorded.
Though not completed as part of this report, the data are collected and formatted
to allow comparison and integration with other datasets developed as a part of the
Thermokarst Mapping Collective. Spatial statistics within each 7.5 km × 7.5 km quartile
are assigned according to the permafrost peatland complex area. For each quartile, the
average percent area covered by a peat plateau complex (▁x) is determined from the
mean of grouped data from the sub-grid cells:
74
𝑥 =∑(𝑓𝑚)
𝑛 [1]
where m is the midpoint of the class bin (Table 4.2), f is the frequency of observations in
each class, and 𝑛 = ∑ 𝑓 (the sum of all observations in the quartile).
Table 4.2: Sub-grid cell permafrost peatland complex area bins and midpoints.
Plateau complex area bin (%) Plateau complex area mid point (%)
Null Null 0 – 2 2
3 – 25 12.5 26 – 50 37.5
51 – 75 62.5 76 – 100 87.5
The area of permafrost peatland complex can be calculated using the information
from Table 4.2 and Equation 1. For example, using the data shown in Table 4.3, the
aggregate percent area in quartile DQ163.4 is:
𝑥 =(1 × 37.5%) + (3 × 62.5%)
4=
225%
4= 56.25%
The secondary conditions within the quartile are aggregated according to the
percent peatland complex area. For example, only two of the sub-grid cells in quartile
DQ163.4 were forested; thus, the amount of forested permafrost peatland complex is:
𝑥 =(2 × 62.5%)
4=
125%
4= 31.25%
And the amount of unforested permafrost peatland complex in DQ163.4 is:
𝑥 =(1 × 37.5%) + (1 × 62.5%)
4=
100%
4= 25%
75
Similar calculations can be carried out to aggregate results to the Quartile-grid
cell for the remaining permafrost peatland complex attributes–degree of degradation
and fire history.
Table 4.3: Mapping results for sub-grid cell DQ163.
AOI cell name
Cell number
Quartile-grid cell
name
Sub-grid cell name
Peatland complex area
(%)
Degree of degradation
Vegetation type
Fire history
DQ163 24227 DQ163.4 DQ163.4.3 62.5 Medium Forested Unburned
DQ163 24227 DQ163.4 DQ163.4.1 62.5 Low Forested Unburned
DQ163 24227 DQ163.4 DQ163.4.4 62.5 Medium Unforested Burned
DQ163 24227 DQ163.4 DQ163.4.2 37.5 Low Unforested Unburned
4.6 Results
4.6.1 Taiga Plains Test Area Results
In the test area (22 922 grid cells, 3.75 km × 3.75 km), 53% of the 3.75 km × 3.75
km sub-grid cells contained permafrost peatland complexes (Figure 4.9a). Additionally,
16% of sub-grid cells were classified as negligible, 21% low, 9% medium, 5% high, and
2% very high (Table 4.4). Of the cells that contained permafrost peatlands, 58% were
forested and 42% were unforested. A total of 2820 grid cells contained permafrost
peatland complexes recently impacted by fire. Data is also presented as 7.5 km × 7.5
km grid cells to complement mapping efforts of other periglacial features (Figure 4.9b).
There were no significant changes in broadscale patterns of permafrost peatland
distributions between the3.75 km × 3.75 km and 7.5 km × 7.5 km grid cells.
The degree of degradation varied across a latitudinal and elevation gradient
within the study area, with greater amounts of thermokarst in the northern extent (Figure
4.10). The degree of degradation also decreases in the centre near Fort Simpson due to
the horn plateau which is raised >300 m around the surrounding area.
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Table 4.4: Estimated extent (number of grid cells) of permafrost peatland complex in total, forested, and unforested landscapes (total n=12 177).
Estimated number of grid cells containing permafrost peatland complexes
None Negligible Low Moderate High Very high
Forested 8153 2392 2943 1562 908 348
Unforested 4024 1402 1834 516 213 59
Total 10 745 3794 4777 2078 1121 407
Figure 4.9: Density distribution of peat plateau complexes in the discontinuous permafrost zone of the Taiga Plains. Data are shown according to both a) sub-grid cell
size (3.75 km × 3.75 km) and b) grid cell size (7.5 km × 7.5 km).
77
Figure 4.10: Degree of degradation (thermokarst) of the permafrost peatland complexes. Visually estimated as low (0% – 33%), moderate (34% – 67%), or High
(67% – 100%).
4.6.2 Quality assessment
A subset of 1185 randomly selected sub-grid cells (~5% of the mapped area)
was assessed by two mappers to test the guidelines on interpretation and the accuracy
of the approach. The mapper overall accuracy for percent area estimates is 89% (Table
4.5). The �� statistic, a measure of the difference between the actual agreement between
the two assessments and the chance agreement between the two, given as:
�� =∑ 𝑥𝑖𝑖𝑟
𝑖=1 −∑ (𝑥𝑖+∙𝑥+𝑖)𝑟𝑖=1
𝑁2−∑ (𝑥𝑖+∙𝑥+𝑖)𝑟𝑖−1
[2]
where r is the number of rows in the error matrix, xii is the number of observations in row
i and column i, xi+ is the total of observations in row i, x+i is the total of observations in
78
column i, and N is the total number of observations included in the matrix. For the
assessment presented in Table 4.5, �� is 0.84, that is, the overall agreement is 84%
better than a chance agreement.
Table 4.5: Table 5. Error matrix resulting from estimating percent extent of peat plateau complex in randomly sampled sub-grid cells (3.75 km × 3.75 km). Bins are estimates of percent cover.
Mapper: CG
0% < 2% 2% - 25% 25% - 50%
50% - 75%
75% - 100%
Row Total
Mapper: JK
0% 8 30 7 0 0 0 555
< 2% 20 180 14 1 0 0 215
2% - 25% 8 23 162 5 0 1 199
25% - 50% 0 0 15 106 6 0 127
50% - 75% 0 0 1 2 58 2 63
75% - 100% 0 0 0 0 0 22 22
Column Total 546 233 199 114 64 25 1181
CG’s Accuracy JK’s Accuracy
0% = 518/546 = 95% 0% = 518/555 = 93%
< 2% = 180/233 = 77% < 2% = 180/215 = 84%
2% – 25% = 162/199 = 81%
2% – 25% = 162/199 =
81%
25% – 50% = 106/114 = 93%
25% – 50% = 106/127 =
83%
50% – 75% = 58/64 = 91%
50% – 75% = 58/63 =
92%
75% – 100% = 22/25 = 88%
75% – 100% = 22/22 =
100%
79
Overall accuracy = (518 + 180 + 162 + 106 + 58 + 22)/1181 = 89%
There was an 85% alignment of the permafrost peatland type (forested/unforested),
with the largest misalignment occurring in mid-latitude regions as forested peatlands
transition to unforested peatlands. There was a 90% agreement in assigning
burned/unburned for fire history. There was an overall 90% agreement in the degree of
degradation with a 94% agreement for high, 92% agreement for low, and a 42%
agreement for medium. The low agreement on the medium degree of degradation
could result from the broad category range making it difficult to decipher at the upper
and lower ends of the bin range.
4.7 Limitations
4.7.1 Data
The primary data limitation is resolution (10-m pixel resolution), which limits the
mapping scale (1:24 000). Higher resolution image data are required to resolve the other
organic permafrost terrain types. However, though higher resolution data are available,
there is a substantial increase in the time and cost to use it for mapping. For the present
purpose, the Sentinel-2 data are deemed adequate.
4.7.2 Mapping
There is an inability to map other types of organic permafrost terrain and several
limitations were encountered during mapping. The first and most basic was human error
during the feature identification and digitization stage. This was minimized by having
mappers use the same feature identification criteria to standardize identification and
digitization of features. In addition, all feature digitization was evaluated by more than one
80
mapper. Lastly, the generation of attribute data was automated through drop-down lists to
reduce human error at the attribute input level.
The second mapping limitation encountered was where the ground was obscured
due to cloud cover or shadow. Cloud cover was minimized by obtaining only those images
with less than 10% cloud cover. Additionally, shadows can obscure the ground making it
difficult to delineate features. However, shadows were generally limited to areas of high
relief such as the Richardson and Mackenzie mountains and were not a problem for
organic terrain mapping in this report.
The third limitation of mapping is the spatial accuracy of the features being mapped
in the imagery, which stems from the orthorectification of the imagery, therefore associated
digitized features may not represent the actual geographic position of the feature on the
ground.
The fourth, the mapping was carried out mainly as a desktop study. Therefore,
limited field verification has been conducted. Features were identified primarily using the
Sentinel-2 imagery. However, the use of supplementary data sources (Google Earth or
ArcGIS Earth) were used to compensate for the lack of field verification. In addition, expert
knowledge was sought from individuals who had been in the field and have worked on
these types of features.
Finally, the mapping was carried out only for a subset of the NWT within one
ecological district and only within sporadic and discontinuous permafrost. This test area
allowed an initial evaluation of the permafrost peatland complex mapping scheme and
refinement, but the evaluation is limited to discontinuous permafrost terrain (in boreal
forest), where permafrost landscapes and thermokarst features are likely to evolve
differently to thaw than other permafrost zones due to contrasting geological, ground ice,
ecological and climate conditions, and variation in disturbance regimes. The resulting data
defines the distribution of permafrost peatlands throughout the Taiga Plains region of the
NWT and the degree to which thermokarst degradation has affected these environments.
81
This product represents phase 1 of mapping organic terrain distribution and thermokarst
effects around 33 NWT communities and then over the entire NWT.
4.8 Digital Data
The output of the peat plateau complex mapping is presented in NWT Open
Report 2020-010 as georeferenced ArcGIS™ Geodatabase format and Shapefile format
files. Metadata, included as an XML file, are annotated in this reports affiliated
Appendix.
4.9 Summary
This report summarizes the methodology to map discontinuous organic permafrost
terrain and to assess the degree of thermokarst degradation in the NWT using Sentinel-
2 satellite images and a uniform grid approach to standardize the mapping. The
methodology is tested using the area corresponding to the sporadic and discontinuous
region of the Taiga Plains ecoregion. Presently, geospatial products that support the
prediction of the extent of permafrost features or terrain vulnerability to permafrost thaw
are either fine scale products that are restricted in extent (Steedman et al. 2016) or
cover a large region but have a low resolution (Olefeldt et al. 2016) and are not suitable
for regional land use planning and risk assessment. The data presented here represent
a significant improvement compared to data previously used for mapping organic terrain
in permafrost environments, as it provides empirically derived fine-scale data over a
large spatial extent. The data presented here can also be aggregated with other gridded
mapping of permafrost features to support a comprehensive understanding of
permafrost features and thaw sensitive terrain across the NWT.
82
4.10 References
Associate Committee on Geotechnical Research (ACGR). 1988. Canadian Glossary of Permafrost and Related Ground-ice Terms, Technical Memorandum No. 142. National Research Council of Canada, Ottawa, ON, 156 pp.
Baltzer, J. L., T. Veness, L. E. Chasmer, A. E. Sniderhan, and W. L. Quinton. 2014. Forests on thawing permafrost: fragmentation, edge effects, and net forest loss. Global change biology 20(3):824–834. https://doi.org/10.1111/gcb.12349
Bonnaventure, P.P., A.G. Lewkowicz, M. Kremer, and M.C. Sawada. 2012. A permafrost probability model for the South Yukon and Northern British Columbia, Canada. Permafrost and Periglacial Processes 23(1):52-68. https://doi.org/10.1002/ppp.1733
Brown, R. J. E. 1967. Permafrost in Canada, Map 1246a of the Geological Survey of Canada. National Research Council of Canada, Ottawa, ON.
Burn, C.R. 1998. The response (1958-1997) of permafrost and near-surface ground temperatures to forest fire, Takhini River valley, southern Yukon Territory. Canadian Journal of Earth Sciences 35(2):194-199. https://doi.org/10.1139/e97-
105
Burn, C. R. 2004. The thermal regime of cryosols. In Cryosols: Permafrost-affected Soils, Kimble, J. M. (ed.). Springer-Verlag, Berlin, Germany, p. 391-413.
Burn, C. R., and C.A.S. Smith. 1988. Observations of the “thermal offset” in near-surface mean annual ground temperatures at several sites near Mayo, Yukon Territory, Canada. Arctic 41(2):99-104.
Carpino, O.A., A. Berg, W.L. Quinton, and J.R. Adams. 2018. Climate change and permafrost thaw-induced boreal forest loss in northwestern Canada.
Environmental Research Letters. 13 084018 https://doi.org/10.1088/1748-9326/aad74e
Chasmer, L., C. Hopkinson, and W. Quinton. 2010. Quantifying errors in discontinuous permafrost plateau change from optical data, Northwest Territories, Canada:
1947- 2008. Canadian Journal of Remote Sensing 36:211–223. https://doi.org/10.5589/m10-058
Chasmer, L. E., and C. Hopkinson. 2017. Threshold loss of discontinuous permafrost and landscape evolution. Global Change Biology 23(7):2672-2686
hhtps://doi.og/10.1111/gcb.13537
83
Collins, M., Knutti, R., Arblaster, J., Dufresne, J.-L., Fichefet, T., Friedlingstein, P., Gao, X., Gutowski, W.J., Johns, T., Krinner, G., Shongwe, M., Tebaldi, C., Weaver, A.J., Wehner, M., 2013. Long-term Climate Change: Projections, Commitments and Irreversibility. In Climate Change 2013: The Physical Science Basis,
Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, p. 1029-1136.
Duk-Rodkin, A., and D. S. Lemmen. 2000. Glacial history of the Mackenzie region; in The Physical Environment of the Mackenzie Valley, Northwest Territories: a Base
Line for the Assessment of Environmental Change, (eds.) L. D. Dyke and G. R. Brooks; Geological Survey of Canada, Bulletin 547, p. 11-20.
Ecosystem Classification Group. Ecological Regions of the Northwest Territories – Taiga Plains. (Department of Environment and Natural Resources, Government
of the Northwest Territories, Yellowknife, 2007).
Fortier, R., A.-M. LeBlanc, and Y. Wenbing. 2011. Impacts of permafrost degradation on a road embankment at Umiujaq in Nunavik (Quebec), Canada. Canadian Geotechnical Journal 48(5):720-740. hhtps://10.1139/t10-101
Gibson, C. M., L. E. Chasmer, D. K. Thompson, W. L. Quinton, M. D. Flannigan, and D. Olefeldt. 2018. Wildfire as a major driver of recent permafrost thaw in boreal peatlands. Nature Communications 9(1) 3041. https://doi.org/10.1038/s41467-018-05457-1
Gignac, L. D., D. H. Vitt, S. C. Zoltai, and S. E. Bayley. 1991. Bryophyte response surfaces along climatic, chemical, and physical gradients in peatlands of Western Canada. Nova Hedwigia 93:29–45. https://doi.org/10.1007/BF00044922
Hjort, J., O. Karjalainen, J. Aalto, S. Westermann, V.E. Romanovsky, F.E. Nelson, B. Etzelmüller, and M. Luoto. 2018. Degrading permafrost puts Arctic infrastructure at risk by mid-century. Nature Communications 9, 5147. https://doi.org/10.1038/s41467-018-07557-4
Islam, M. A. and S.E. Macdonald. 2004. Ecophysiological adaptations of black spruce (Picea mariana) and tamarack (Larix laricina) seedlings to flooding. Trees—Structure and Function 18:35–42 https://doi.org/10.1007/s00468-003-0276-9
Kokelj, S. V, and M. T. Jorgenson. 2013. Advances in Thermokarst Research. Permafrost and Periglacial Processes 24(2):108–119.
https://doi.org/10.1002/ppp.1779
84
Koven, C. D., W. J. Riley, and A. Stern. 2013. Analysis of permafrost thermal dynamics and response to climate change in the CMIP5 Earth system models. Journal of Climate 26:1977-1900. https://doi.org/10.1175/JCLI-D-12-00228.1
Lemmen, D. S., Duk-Rodkin, A., and J. M. Bednarski. 1994. Late glacial drainage systems along the northwest margin of the Laurentide Ice sheet. Quaternary Science Review 13:805-828. https://doi.org/10.1016/0277-3791(94)90003-5
Loisel, J. et al. 2014. A database and synthesis of northern peatland soil properties and Holocene carbon and nitrogen accumulation. Holocene 24, 1028–1042.
https://doi.org/10.1177/0959683614538073
Mackay, J. R. 1972. The world of underground ice. Annals of the Association of American Geographers 62(1):1-22. https://doi.org/10.1111/j.1467-8306.1972.tb00839.x
Morse, P. D., and C. R. Burn. 2013. Field observations of syngenetic ice wedge polygons, outer Mackenzie Delta, western Arctic coast, Canada. Journal of Geophysical Research Earth Surface 118(3):1320-1332. https://doi.org/10.1002/jgrf.20086
Nelson, F., S.I. Outcalt, C.W. Goodwin, and K. M. Hinkel. 1985. Diurnal thermal regime in a peat covered palsa, Toolik Lake, Alaska. Arctic 38:310-315. https://doi.org/10.14430/arctic2150
O’Neill, H.B. and C.R. Burn. 2017. Impacts of variation in snow cover on permafrost stability, including simulated snow management, Dempster Highway, Peel Plateau, Northwest Territories. Arctic 3(2):150-178. hhtps://doi.org/10.1139/AS-2016-0036
Olefeldt, D., S. Goswami, G. Grosse, D. Hayes, G. Hugelius, P. Kuhry, V.E. Romanovsky, A.B.K. Sannel, E.A.G. Schuur, and M.R. Turetsky. 2016. Circumpolar distribution and carbon storage of thermokarst landscapes. Nature Communications, 7:1–11. https://doi.org/10.1038/ncomms13043
Pelletier, N., J. Talbot, D. Olefeldt, M. Turetsky, C. Blodau, O. Sonnentag, and W.L. Quinton. 2017. Influence of Holocene permafrost aggradation and thaw on the paleoecology and carbon storage of a peatland complex in northwestern Canada. Holocene 27, 1391–1405 (2017). https://doi.org/10.1177/0959683617693899
Romanovsky, V. E., and T. E. Osterkamp. 1995. Interannual variations of the thermal regime of the active layer and near surface permafrost in Northern Alaska.
85
Permafrost and Periglacial Processes 6(4):313-335. https://doi.org/10.1002/ppp.3430060404
Shur, Y. L., and K. M. Hinkel, and F. E. Nelson. 2005. The transient layer: implications for geocryology and climate science. Permafrost and Periglacial Processes
16(1):5-17. https://doi.org/10.1002/ppp.518
Schuur, E. A. G, and B. Abbott. 2011. High risk of permafrost thaw. Nature 480:32-33. https://doi.org/10.1038/480032a
Schuur, E. A. G., J. G. Canadell, S. V. Goryachkin, P. Kuhry, N. Shiklomanov, P. M. Lafleur, A. Rinke, S. Hagemann, J. G. Vogel, V. E. Romanovsky, G. Mazhitova, C. Tarnocai, H. Lee, J. Bockheim, F. E. Nelson, C. B. Field, E. Euskirchen, E. A. G. Schuur, S. A. Zimov, and S. Venevsky. 2008. Vulnerability of Permafrost Carbon to Climate Change: Implications for the Global Carbon Cycle. BioScience
58(8):701–714. https://doi.org/10.1641/B580807
Steedman, A.E., T.C. Lanz, and S.V. Kokelj. 2016. Spatio-temporal variation in high-centre polygons and ice-wedge. Permafrost and Periglacial Processes 28(1):66-78. https://doi.org/10.1002/ppp.1880
Williams, P. L., and M. W Smith. 1989. The Frozen Earth: Fundamentals of Geocryology. Cambridge University Press, Cambridge, UK. 306 pp.
Zoltai, S. C., and C. Tarnocai. 1975. Perennially Frozen Peatlands in the Western Arctic and Subarctic of Canada. Canadian Journal of Earth Sciences 12:28–43.
https://doi.org/10.1139/e75-004
Zoltai, S. C. 1993. Cyclic Development of Permafrost in the Peatlands of Northwestern Canada. Arctic and Alpine Research 25(3):240–246. https://doi.org/10.2307/1551820
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5 Mapping and understanding the vulnerability of northern peatlands to permafrost thaw at scales relevant to community adaptation planning
5.1 Abstract
Developing spatially explicit permafrost datasets and climate assessments at
scales relevant to northern communities is increasingly important as land users and
decision makers incorporate changing permafrost conditions in community and
adaptation planning. This need is particularly strong within the discontinuous permafrost
zone of the Northwest Territories (NWT) Canada where permafrost peatlands are
undergoing rapid thaw due to a warming climate. Current data products for predicting
landscapes at risk of thaw are generally built at circumpolar scales and do not lend
themselves well to fine-scale regional interpretations. Here, we present a new
permafrost vulnerability dataset that assesses the degree of permafrost thaw within
peatlands across a 750 km latitudinal gradient in the NWT. This updated dataset, driven
by the need for spatially relevant datasets for communities, decreases the estimated
area of high or highly vulnerable permafrost by over 90% compared to the circumpolar-
scale products. We show that permafrost thaw affects up to 70% of the area of peatland
complexes within the study area and that thaw is strongly mediated by both latitude and
elevation. At northern end of our latitudinal gradient, peatland permafrost remains
climate-protected with relatively little thaw. However, at the southern end, widespread
thaw has occurred with the greatest thaw vulnerability at low elevations. Collectively
these results demonstrate the importance of scale in permafrost analyses and mapping
if research is to support northern communities and decision makers in a changing
climate. This study offers a more scale-appropriate approach to support community
adaptative planning under scenarios of continued warming and widespread permafrost
thaw.
87
5.2 Introduction
Climate change at high latitudes is causing rapid and unprecedented
environmental change (ACIA 2005; Chapin 2005) as the rate of warming across the
Arctic has been three or four times that of the global average in recent decades
(Bekryaev et al 2010; Christensen et al. 2013; Jeffries et al. 2013; IPCC 2018). The
future impacts of climate warming on communities and infrastructure is one of the most
pressing issues facing the world today (IPCC 2018). A unique challenge that northern
communities face in a warming climate is the widespread thawing of permafrost. It is
predicted that by the mid-21st century, the area of permafrost in the northern
hemisphere will decline by 20 – 35 % (IPCC 2018). Given this, northern communities
are increasingly asking for decision support tools that will aid in adaptation planning by
assessing where and when permafrost thaw is going to occur (Melvin et al 2017).
Across the discontinuous permafrost zone of the Northwest Territories (NWT),
thermokarst is a common permafrost-related disturbance in northern peatlands.
Permafrost peatlands typically occur as complexes of areas with intact surface
permafrost (often referred to as peat plateaus or palsas) interspersed with thermokarst
bogs. Thermokarst refers to the subsidence and land cover change that results from
thawing of permafrost in some areas, particularly regions with high ground ice content
(Kokelj and Jorgenson 2003). In the NWT, thermokarst causes the conversion of
permafrost peat plateaus to permafrost-free thermokrast bogs and shallow open water
wetlands (Zoltai and Tarnocai 1974). Historically, permafrost peatlands in this region
underwent a cycle of degrading permafrost followed by permafrost recovery and
aggradation over an approximate 500-year period (Zoltai 1993). During the degradation
or thermokarst phase, the land subsides which increases saturation causing black
spruce (Picea mariana) die off and replacement by highly productive Sphagnum spp.
mosses. Over time, surface peat accumulation would lead to drier surface soils and
greater woody plant establishment, allowing permafrost to begin to form again (Zoltai
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1993). However, in a warming climate (IPCC 2018) with higher-intensity disturbance
regimes (Kasischke and Turetsky 2006, Wang et al 2015) rates of thermokarst
formation are accelerating. In the NWT, rates of thermokarst formation in peatlands
increased three-fold after disturbance like wildfire (Chasmer et al 2010, Baltzer et al
2014, Gibson et al 2018). In many peatland-rich regions, ongoing climate change has
surpassed the threshold required for permafrost recovery, meaning that permafrost
thaw is irreversible (Camill 2005, Baltzer et al 2014, Gibson et al 2018, Jorgenson et al
2006).
Broadly, thermokarst formation can cause a cascade of direct and indirect
effects, and these interact with local hydrology (e.g. Quinton and Marsh 1999, Smith et
al 2007, Wright et al 2009, Tank et al 2016, McGuire et al 2018) to drastically affect
community infrastructure (Melvin et al 2017, Addison et al 2016), traditional land use
(Andrews et al 2016), soil mercury concentrations (Gordon et al 2016), and food
security (Calmels et al 2015). Given these widespread and diverse impacts on
ecosystem processes and services, communities and land-users will increasingly need
to consider changes in permafrost within their adaptation and planning efforts (Flynn et
al 2019). To do this effectively, there has been an increased desire and demand for
permafrost modeling and vulnerability data to help inform community planning and land
use planning in a warming, uncertain future. To support the development of these
products (modelling and vulnerability data), geospatial analyses that describes the
nature and intensity of permafrost thaw and its spatial distribution are required.
Presently, the best available data products for predicting vulnerable permafrost
are either developed at circumpolar scales using modeled products (e.g. Olefeldt et al
2016), or are small in geographic scope, for example using fine-scale measurements for
infrastructure citing projects (e.g. Flynn et al 2019). Some recent studies at regional
scales focus on ice wedge degradation or thermokarst formation in uplands (Steedman
et al 2017, Fraser et al 2018, Rudy et al 2017). For peatland-rich regions; however, the
Olefeldt et al. (2016) circumpolar thermokarst maps currently offer the best description
89
of vulnerability to thermokarst formation. As noted above, thermokarst in peatlands
affects terrain stability and land use but also is relevant to conservation, wildlife, and fire
management policies and planning. All of these issues require new geospatial efforts at
regional to local scales.
Because permafrost is a product of climate, ground temperatures are warming in
response to rising air temperatures (Biskaborn et al 2019). As such, mean annual air
temperature is one of the most important and commonly used predictors of thaw rates
(McGuire et al 2018, Schaefer et al 2014, Lawrence et al 2015). However, some of the
most rapid thermokarst rates are occurring in cold-climates (Lewkowicz and Way 2019),
a strong illustration that other factors affect the rate and extent of thermokarst formation.
In the Taiga Plains region of the Northwest Territories, mean annual air temperature
ranges from -1.3°C to -8.4°C. Thus, communities in this region experience very
different air and ground temperatures as well as other factors such as topography and
elevation (Figure 5.1a) (Fick and Hijmans 2017), all of which interact to govern thaw
vulnerability. The goal of this study was to work across a latitudinal gradient in the Taiga
Plains region designed to encompass some of this climatic and permafrost variability.
Our geospatial analyses differentiated areas where permafrost has already thawed
versus permafrost peatland areas that remain susceptible to thermokarst formation in
the future. Our goals were to 1) update permafrost peatland vulnerability maps at local
scales along this latitudinal gradient and compare them to the results of existing
circumpolar-scale thaw products, 2) assess how the degree of thermokarst formation
within permafrost peatlands varies with latitude and mean annual temperature. We use
trends across the latitudinal gradient as a space-for-time substitution to make inferences
about how thaw may progress in a warming climate, and 3) determine the role of other
topographical controls (such as elevation) on thermokarst formation and its importance
for identifying vulnerable permafrost at community scales. Understanding both current
and future patterns of thermokarst formation in peatlands, as well as major climatic or
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geophysical drivers of thaw, will be important in our goal of supporting the communities
whose livelihoods depend on permafrost environments.
5.3 Study Area
This study covers an area of 372 220 km2 in the southern portion of the
Northwest Territories and covers the discontinuous permafrost zone of the Taiga Plains
Ecozone (Figure 5.1a). Mean annual air temperature varies from -1.3°C to -8.4°C.
Figure 5.1: A) Map of study region (372 220 km2), representing the extent of the discontinuous permafrost zone within the Taiga Plains Ecozone with the Northwest Territories, Canada. Variation in elevation across the study region is shown (CDEM –
Natural Resources Canada, 2016). Communities across the study region reside in elevationally different positions, and community land users interact with these elevational conditions as they travel across the landscape. Base maps provided by Esri, DigialGlobe, Geo eye (ArcGIS version 10.3). The bottom left inset shows the location of
the study area relative to northern Canada. B) Example permafrost peatland complex
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(61°14'6.79"N, 117°35'23.81"W). Peat plateaus represent areas where the permafrost is intact, while thermokarst areas are those in which abrupt permafrost thaw (thermokarst) has occurred. Peatland complex area = peat plateau area + thermokarst area. GeoEye satellite image obtained online https://zoom.earth.
This area is characterized by a subdued relief and gently rolling plains. It is
underlain with horizontal beds of sedimentary rocks consisting of limestone, shale,
sandstone, and conglomerates. The imprint of glacial legacy dominates the
contemporary landscape. Surficial deposits range from hummocky till, to glacially fluted
terrain that has yielded vast aligned/oriented wetland and lake systems, to large
lacustrine plains deposited by former glacial lakes, the largest being Glacial Lake
McConnell. Post glacial incision of the Mackenzie River and its tributaries have
improved drainage through the region and yielded fluvial deposits along the river
valleys. However, vast low-lying areas across the region have remained poorly drained,
favouring accumulation of organic materials and peatland development. As a result, this
area is one of the major peatland areas of Canada and nearly 40% of the study area is
peatlands (Ecosystem Classification Group 2007). Peat accumulation in this area
initiated following deglaciation ~9000 years ago (Loisel et al 2014) and is strongly
related to climate as well as to local moisture and drainage conditions, with peat depths
varying between 2 and 6 m. Permafrost aggradation began during the climate cooling
after the Holocene thermal maximum ~5000 years ago, and became more widespread
following further cooling 1200 year ago (Pelletier et al 2017).
Permafrost peatlands in this area are a mosaic of permafrost peat plateaus
raised 1 – 2 m above surrounding permafrost-free bogs and fens. For clarity, the
following definitions are used to guide the mapping and analysis as part of this study
(Figure 1b):
• Peat plateau area: The area where permafrost remains and elevates the surface
1 – 3 m above the surrounding landscape due to high ground ice content.
Characterized by a relatively dry surface that supports black spruce (Picea
mariana), evergreen shrubs such as Labrador tea (Rhododendron
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groenlandicum), and lichen and moss cover (Cladina spp. and Sphagnum spp,
respectively).
• Thermokarst area – The permafrost-free bogs that have formed following
permafrost thaw. These bogs are characterized by highly saturated soils and
vegetation dominated by Sphagnum spp. and sedges.
• Peatland complex area – The entire peatland that encompasses both peat
plateaus and thermokarst bog area.
5.4 Methods
5.4.1 Updating permafrost peatland vulnerability maps at local scales
To update permafrost peatland vulnerability maps at local scales within the
discontinuous permafrost zone of the Northwest Territories, the 372 220 km2 study area
was mapped using Sentinel 2 imagery (Sentinel-2A, B04 (Red), B03 (Green), B02
(Blue), 10-m, 2016 and 2017, July and August). Peatland complex area was visually
mapped using a 3.75 × 3.75 km grid cells using the percent cover of permafrost
peatland complex area per grid cell. The grid cell classes include none (0% coverage),
negligible (<2%), low (3 – 25%), moderate (26 – 50%), high (51 – 75%), and very high
(76 – 100%). A subset of study area (~5% of the mapped area) was assessed by 2
mappers in order to test the guidelines on interpretation and the accuracy of the
approach. With respect to percent area estimates, overall mapper accuracy is 89%. The
data was compiled and all GIS analysis was completed using ArcGIS (ESRI, 2014,
version 10.2.2, Redlands, CA, USA). For complete methods and data see Gibson et al.
(2020). Given the cyclical lifecycle, and high-ice content properties of peatland
permafrost (Zoltai 1993), we consider any intact permafrost peatland to be predisposed
to thermokarst formation.
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5.4.2 Assessment of the degree of thermokarst formation across a latitudinal gradient
To assess how the degree of thermokarst formation within permafrost peatland
varies across the climatic gradient, we visually quantified the proportion of peatland
complex area that had undergone thermokarst formation using the ESRI World Imagery
map downloaded from ArcGIS.com (World Imagery (arcgis.com). Mosaiced satellite
imagery used in this interpretation were acquired during the growing season (May to
September) from 2009 to 2019. All data were provided to the World Imagery archive by
Maxar Inc. Data were acquired at varying pixel resolutions between 0.31 and 0.6 m
collected using GeoEye-1, WorldView2, WorldView3 and Quickbird-2. Visual
estimations are possible due to the distinct vegetation differences between thermokarst
bogs and intact permafrost peat plateaus that are clearly discernable on RGB (optical)
high resolution satellite imagery (Figure 5.1b).
To determine how the proportion of peatland complex that has thawed varied
across the study region, 3.75 × 3.75 km grid cells with high and very high estimates of
permafrost peatlands were first identified. This ensured that we were comparing similar
peatlands areas across a latitudinal gradient and that differences in the amount of thaw
is not being driven by other factors that are occurring at smaller scales in small
peatlands. Furthermore, from a community perspective, it is likely that thawing of large
permafrost peatlands will have the most impact on their land use regarding travel
(Gibson et al. 2020) and changes in hydrology (Quinton et al 2011a).
A subset of these identified cells where then randomly selected (n=70, or ~5%).
Selected grid cells spanned the entirety of the study area and had high resolution
ArcGIS DigitalGlobe, Geo Eye basemap (ArcGIS version 10.3) imagery available.
Selected grid cells where then overlain with a 10 × 10 grid (creating 100 sub-grid cells
with size equal to 375 × 375 m). Of the 100 sub grid cells, those contained within the
peatland complex area were identified visually and 10 random cells of those were
selected to determine the degree of thermokarst formation (Figure 5.2). In the selected
sub grid cells, we visually estimated the percent of the peatland complex with
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thermokarst formation. Estimates were made in intervals of 10 (i.e. 0%, 10%, 20%, 30%
coverage etc). The mean percent of peatland complex area that was thawed and
standard deviation for each 3.75 × 3.75 km grid cell was calculated.
To assess how the proportion of peatland complex that has thawed varied across
a climatic gradient, mean annual air temperature was estimated from WorldClim 2.1
climate model (Fick and Hijmans 2017). This dataset is a grid (resolution = 1 km2) of
average monthly temperature interpolated from weather station data (1970 – 2000).
Long time series of historical observations of climate and hydrology are scarce in the
Northwest Territories, therefore gridded datasets have been used as alternatives to
instrumental observations for climate analysis (Persaud et al. 2019; Segal et al. 2016).
The mean annual air temperature from the WorldClim 2.1 climate model was assigned
to each grid cell using the zonal statistics tool (ESRI Redlands, 2020). Given the high
collinearity between mean annual air temperature and latitude (R2=0.95) and the greater
certainty in latitude compared to mean annual air temperature, latitude was used in all
subsequent analyses.
The proportion of thawed peatland complex area was linearly regressed against
latitude. The scatterplot was visually assessed for trends in thermokarst formation to
make inferences about how thaw may progress in a warming climate. This data was
also binned into three bins (59.9°N - 62°N, 62°N – 64.1°N, and 64.1°N - 66.1°N) and
statistically tested for differences in the proportion of peatland complex thawed using an
ANOVA. The binned data was also statistically tested for differences in variance using
a Fligner-Killeen Test of Homogeneity of Variances for non-normally distributed data
(Williams et al. 1981).
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Figure 5.2: Process of estimating the extent of thermokarst formation within selected 3.75 × 3.75 km grid cell. A) random selection of ‘high’ or ‘very high’ classified grid cells across the study area. B) selection 10 random sub-grid cells 375 × 375 m in size. C) Visual percent estimates of thermokarst bog within the sub grid cell.
5.4.3 Elevational controls on thermokarst formation
To assess the potential for elevational controls on thermokarst formation,
elevation data was derived from the 0.75 -arcsec (20 m) Canadian Digital Elevation
Model (CDEM – Natural Resources Canada 2016). Individual CDEM tiles were
mosaiced to the extent of the study area and mean elevation was assigned to each grid
cell using the zonal statistic tool (ESRI Redlands, 2020). Visual assessments and
interpretations were made to determine how elevation influenced the proportion of
thermokarst formation within an individual bin and between bins. This was assessed
using multiple linear regression analysis with a model of the proportion of thermokarst
with the main effects of latitude and elevation.
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5.5 Results
Figure 5.3: Map showing the density distribution of permafrost peatlands in the discontinuous permafrost zone of the Taiga Plains. Data are shown according to grid cell size 3.75 × 3.75 km.
5.5.1 Proportion of peatland complex that has thawed across a latitudinal gradient
The mapping of a 322 340 km2 area of northwestern Canada confirmed
widespread coverage of permafrost peatlands. In total, 53% of the grid cells contained
permafrost peatlands (Figure 5.3) with 16% classified as negligible, 21% low, 9%
medium, 5% high, and 2% very high cover. The proportion of peatland complex already
containing thaw ranged from 3 ± 3% to 77 ± 12% within the study area. The proportion
of peatland complex thawed also varied along a latitudinal gradient with greater
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proportions of thermokarst formation in peatland complexes in the south compared to
the north (Figure 5.4a). The proportion of peatland complex thawed varied between
latitudinal bins (Figure 5.4a inset; ANOVA, p <0.001, F=73.89). Additionally, there was
greater variability in the proportion of peatland complex thawed in southern permafrost
peatlands compared to northern ones (Fligner-Killeen test of homogeneity of variances,
p < 0.001, Figure 4a inset). This was also apparent from increased scatter around the
regression line.
Figure 5.4: A) Relationship between latitude and the proportion of peatland complexes
that have thawed due to thermokarst formation. Colour represents mean annual air temperature (Fick and Hijmans 2017). Inset figure shows the proportion of peatland complex’s thawed in three latitudinal bins that are significantly different from each other in their proportion thaw. B) Proportion of peatland complex thawed binned by latitudinal
classes; data also are visualized by elevation. Larger light green dots represent higher elevations while smaller dark green dots represent lower elevations.
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5.5.2 Elevational controls on thermokarst formation
Elevation appears to govern the proportion of thermokarst formation within
peatland complexes at lower latitudes (Figure 5.4b). Our results suggest that latitude
and elevation together improved prediction of thermokarst formation compared to
latitude or mean annual air temperature alone (p <0.001). Furthermore, the proportion
of thermokarst formation was significantly correlated to elevation for the lower (linear
model, p = 0.004 ) and mid latitude (linear model, p =0.006) bins, but not for the high
latitude bin (linear model, p =0.8). We infer that the increased variance in the proportion
of thermokarst formation at lower latitudes is being driven by this elevation effect,
whereby higher elevation peatlands remain protected from increasing temperatures.
5.6 Discussion
5.6.1 Updated permafrost peatland vulnerability map
The permafrost peatland vulnerability map effectively characterized and identified
areas susceptible to peatland thermokarst formation at a scale that is of increased use
and value to communities. When compared our results to the Olefeldt et al. (2016)
circumpolar-scale dataset, the proportion of the study area that is high or very highly
vulnerable to thermokarst changes from 61% under the circumpolar approach to just 6%
according to our results (Figure 5.5). This represents a 90% decrease in the predicted
area of high or very highly vulnerability. This significant decrease in the area of
permafrost deemed vulnerable to thaw is important to community and territorial
planners, particularly given that proactive planning based on the potential for permafrost
thaw is typically more cost-effective than retrofitting infrastructure (Melvin et al 2017).
Accurate and appropriately scaled vulnerability maps are critical for supporting high
level landscape planning, cumulative effects assessments within environmental
assessments, and for environmental management through range planning. Our results
show large discrepancies with the coarse-scale thaw vulnerability probabilities
presented in Olefeldt et al. (2016); however it was beyond the scope of this study to
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determine how generalizable this trend is for permafrost peatland regions in other
locations. It is possible that the input spatial datasets utilized in the framework in
Olefeldt et al. (2016) simply do not perform well in the Northwest Territories or in
northwestern Canada. Comparisons between regional-scale and global-scale mapping
products such as what is presented but applied to other regions here may offer the
ability to refine the broader-scale systems, for example by highlighting the importance of
the latitude × elevation interaction in our study region.
We note that there are challenges in using these data to identify ‘hazard
potential’ from thawing permafrost. A key limitation of this current dataset is that it
assesses permafrost peatland complex area and does identify the amount of
thermokarst within the complex. ‘High’ classified grid cells in the north versus south can
contain similar amounts of permafrost peatlands; however, they likely will vary in the
proportion of the peatland that has thawed (Figure 5.4a). In the southern areas, certain
peatlands have already experienced a significant amount of thaw and their potential for
future hazard may be more limited than peatlands located further north. For a detailed
description of the dataset’s limitations see Gibson et al. (2020).
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Figure 5.5: Comparison of geospatial products of lowland thermokarst probability in permafrost peatlands in the discontinuous permafrost zone of the Taiga Plains Ecozone within the Northwest Territories, Canada. (A) The Olefeldt et al. (2016) framework was developed for use at circumpolar scales. (B) Results from this study uses a gridded
approach and was developed for use at regional or community-relevant scales. (C) Comparison of these two approaches binned by predisposition classes. Note that a negligible class does not exist within the Olefeldt et al. (2016) framework; thus we combined the “none” and “negligible” classes in this analysis. For larger versions of the
maps see Gibson et al. (2020).
Having appropriately scaled permafrost vulnerability maps is also important at
community scales as the use of circumpolar scale assessments can lead to feelings of
eco-anxiety (Cunsolo and Ellis 2018). Community members are not trained on the
nuances of circumpolar scale assessments and therefore are more likely to just
visualize the maps as large areas of red, orange, yellow, and grey. The large red
polygons created by circumpolar scale assessments may contribute a feeling of
hopelessness in the face of climate change (Cunsolo and Ellis 2018), as large areas of
their traditional territories are ‘at high risk of abrupt thaw. The updated permafrost
peatland vulnerability dataset helps to address the subjective concept of permafrost risk
(Aven and Renn 2010) in which community members are likely to carry their own risk
narratives (including past experiences with permafrost thaw) and apply it to any
mapping product (Sutherland et al. 2012). The updated vulnerability dataset provides a
more manageable perspective of risk and allow for a more effective identification of ‘hot
spots’, and conversely also “cold spot” areas that are deemed less vulnerable to
landscape change in the face of warming and permafrost thaw. Furthermore, the
scientific community has an obligation to communicate the relevance and intended uses
of geospatial products.
The grid-based mapping approach used in this study allowed for improved spatial
resolution and continuous coverage while balancing the time required to analyze and
interpret the satellite imagery. Rather than “mapping” with points, lines and polygons,
grid-based mapping allowed us to effectively record the locations of permafrost
peatlands and identify high density area of peatlands. Grid-based mapping provides an
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efficient solution to the problems of mapping small landforms over large areas, by
providing a consistent and standardized approach to spatial data collection (e.g. Segal
et al. 2018). The simplicity of the grid-based mapping approach makes it extremely
scalable and workable for group efforts, requiring minimal user experience and
producing consistent and repeatable results (Ramsdale et al 2017). Although the grid-
based assessment cannot identify the specific locations that thaw has or is likely to
occur within the permafrost peatlands (i.e. does not identify specific thermokarst
locations), what it does provide is a higher order assessment of where vulnerable areas
are located. These vulnerable areas can then be assessed against important and
traditional areas of communities to help direct and inform where finer scale studies and
efforts should be applied (Andrews et al. 2016). This approach is feasible because
thermokarst in peatlands leads to surface changes that are easily detected. In other
situations (such as active layer thickening), permafrost thaw may not be easily detected
from surficial changes.
5.6.2 Thawed permafrost peatland areas with variation in latitude and elevational controls
The latitudinal effect on the proportion of thaw in permafrost peatland complexes
illustrates the potential for continued widespread thawing across the discontinuous
permafrost zone of the NWT. A near 70% difference in the proportion of thermokarst
area in our study region occurs across a ~3-4°C difference in air surface temperatures
(Fick and Hijmans 2017). In response to these air temperatures, mean annual ground
temperatures range from > 0°C in the southern portion to -2°C in the northern portion of
our study region (Smith et al 2010). Mean annual air temperatures in our study area are
expected to rise by 3°C by 2100 (IPCC 2018). Altogether, this suggests that the ground
temperatures and thaw-extent in the northern extent of the study area in the future will
be similar to those currently observed in the southern extent of the study area today.
Jorgenson et al. (2020) concluded that permafrost thaw in interior Alaska, with mean air
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temperatures of -2.4°C, has already reached a tipping point with irreversible thaw. If this
is true in the NWT, we speculate that by 2100 as much as 70% of northern permafrost
peatlands will have thawed permanently.
We were surprised by the linear relationship between latitude and proportion of
thermokarst. We had predicted there would be nonlinear evidence of abrupt ecological
change, defined as a substantial change in ecosystem states over relatively short
periods of time when compared to typical rates of change (Ratajczak et al 2018). Abrupt
ecological changes are increasing being reported in nature due a warming climate and
spans diverse ecosystems and scales (Bestelmeyer et al 2011, Cloern et al 2015,
Rocha et al 2015, Thomson et al 2015, Westerling 2016). In this study, it was expected
there would be a nonlinear response in the proportion of thermokarst area across the
latitudinal gradient as Baltzer et al. (2014) showed an exponential increase in the rate of
thaw (i.e. percent plateau loss per year) with climate warming using a time series
analysis. Although this study shows no evidence of nonlinearity in the proportion of
thermokarst area within permafrost peatlands, it could be occurring within discrete
ecological areas as opposed to the larger ecological gradient we used in our space-for-
time substitution. If so, additional work is needed using time series analysis to test for
non-linearities within permafrost peatlands.
Our latitudinal gradient and opportunity to think about a space-for-time
substitution allowed us to speculate about how northern climate-protected permafrost
peatlands may be impacted by future warming. We do, however, acknowledge that our
approach assumes that northern permafrost peatlands will respond to climate warming
in the same way southern permafrost peatlands have. This will be complicated by
complex interconnected controls on thermokarst formation including but not limited to
permafrost thickness, subsurface condition, drainage and more (e.g. Quinton et al
2011b, Quinton and Baltzer 2013, Baltzer et al 2014). However, despite these cautions
and caveats, space-for-time approaches are commonly used as one approach for
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providing insights into potential ecosystem changes associated with climate change
(Dieleman et al 2020, Pokrovsky et al 2020).
One of the key challenges for predicting how and when these permafrost
peatlands will respond to warming is that projections often depend on accurate mean
annual air temperature data. The NWT is data sparse (GNWT 2018). Mean annual air
temperature data for the study region (372 220 km2) is only based on two weather
reporting stations (Environment Canada 2016). While the resulting interpolation may be
sufficient for large scale climate and permafrost modeling, predicting finer scale patterns
and processes is difficult. If we are to support community adaptation and planning to
changing permafrost conditions, we will require a better understanding of regional
differences in mean annual air temperature (i.e. more long term climate monitoring).
This study also demonstrates the importance of considering fine-scale regional
differences in elevation when assessing trends in thermokarst formation. Our results
show substantial variance in thaw-extent at lower latitudes. We attribute this to
differences in elevation, in which higher elevation peatlands are more protected from
increasing temperatures than lower elevational peatlands, and are generally far better
drained (Figure 5.5). We assumed that permafrost in northern peatlands would be more
climate protected than southern peatlands in our study region, but these results suggest
that peatland permafrost also can be resistant to change due to high elevation. This
finding, coupled with the known mean annual air temperature sparsity within the study
area, introduces the need more fine-scale data. We recommend that fine-scale data
collection of mean annual air temperatures and mean annual ground temperatures is
prioritized in order to make more valid predictions of future permafrost thaw in and
around communities.
5.6.3 Conclusion
As northern regions experience widespread permafrost thaw, northern
communities need access to spatially-relevant decision support tools. Currently, the
best available data products for predicting permafrost vulnerability to thaw are
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developed at circumpolar scales (e.g. Olefeldt et al 2016) or are very small in
geographic scope (e.g. Flynn et al 2019). In this study we present an updated, spatially-
relevant dataset for predicting permafrost peatlands area and thaw extent in the
discontinuous permafrost zone of the Northwest Territories. This updated data product
provides a more spatially explicit understanding of vulnerable permafrost peatlands and
decreases the predicted area of ‘high or highly vulnerable’ permafrost peatlands by
nearly 90%. Furthermore, we found a strong latitudinal effect on the proportion of thaw
within permafrost peatland complexes, with near total loss of permafrost in the southern
extent. Using this relationship in a space-for-time substitution along with climate
projections for our study region, we suggest that most permafrost in peatlands across
our entire latitudinal gradient across the discontinuous permafrost zone in the NWT will
be permanently thawed by 2100. However, we show that thaw will be mediated by
elevational differences, and that permafrost in higher elevational peatlands will be more
resistant to thaw than peatlands in low elevation environments. Because northern
community members interact with diverse landscapes as they access the land for
hunting, gathering, and cultural activities, these differences governing the trajectory of
thaw will be important to consider in regional ecosystem and infrastructure planning.
5.7 References
Addison P, Lautala P and Oommen T 2016 Utilizing Vegetation Indices as a Proxy to Characterize the Stability of a Railway Embankment in a Permafrost Region AIMS Geosci. 2 329–44
Andrews T D, Kokelj S V, MacKay G, Buysse J, Kritsch I, Andre A and Lantz T 2016
Permafrost Thaw and Aboriginal Cultural Landscapes in the Gwich’in Region, Canada APT Bull. J. Preserv. Technol. 47 15–22
Baltzer J L, Veness T, Chasmer L E, Sniderhan A E and Quinton W L 2014 Forests on thawing permafrost: fragmentation, edge effects, and net forest loss. Glob.
Chang. Biol. 20 824–34
105
Bekryaev R V., Polyakov I V. and Alexeev V A 2010 Role of polar amplification in long-term surface air temperature variations and modern arctic warming J. Clim. 23 3888–906
Bestelmeyer B T, Peters D P C, Pillsbury F C, Holbrook S J, Rassweiler A, Sharma S,
Schmitt R J, Laney C M, Fraser W R, Ellison A M, Gorman K B and Ohman M D 2011 Analysis of abrupt transitions in ecological systems Ecosphere 2
Biskaborn B K, Smith S L, Noetzli J, Matthes H, Vieira G, Streletskiy D A, Schoeneich P, Romanovsky V E, Lewkowicz A G, Abramov A, Allard M, Boike J, Cable W L,
Christiansen H H, Delaloye R, Diekmann B, Drozdov D, Etzelmüller B, Grosse G, Guglielmin M, Ingeman-Nielsen T, Isaksen K, Ishikawa M, Johansson M, Johannsson H, Joo A, Kaverin D, Kholodov A, Konstantinov P, Kröger T, Lambiel C, Lanckman J P, Luo D, Malkova G, Meiklejohn I, Moskalenko N, Oliva M,
Phillips M, Ramos M, Sannel A B K, Sergeev D, Seybold C, Skryabin P, Vasiliev A, Wu Q, Yoshikawa K, Zheleznyak M and Lantuit H 2019 Permafrost is warming at a global scale Nat. Commun. 10 1–11
Calmels F, Laurent C, Brown R, Pivot F and Ireland M 2015 How Permafrost Thaw May
Impact Food Security of Jean Marie River First Nation, NWT GeoQuebec 2015 Conf. Pap.
Camill P 2005 Permafrost thaw accelerates in boreal peatlands during late-20th century climate warming Clim. Change 68 135–52
Chapin F S 2005 Role of Land-Surface Changes in Arctic Summer Warming Science (80). 310
Chasmer L, Hopkinson C and Quinton W 2010 Quantifying errors in discontinuous permafrost plateau change from optical data, Northwest Territories, Canada:
1947-2008 Can. J. Remote Sens. 36 S211–23
Cloern J E, Grall J, Xu J, Greening H, Abreu P C, Yin K, Sherwood E T, Kahru M, Johansson J O R, Chauvaud L, Elmgren R and Carstensen J 2015 Human activities and climate variability drive fast-paced change across the world’s
estuarine-coastal ecosystems Glob. Chang. Biol. 22 513–29
Cunsolo A and Ellis N R 2018 Ecological grief as a mental health response to climate change-related loss Nat. Clim. Chang. 8 275–81 Online: http://dx.doi.org/10.1038/s41558-018-0092-2
Dieleman C M, Rogers B M, Potter S, Veraverbeke S, Johnstone J F, Laflamme J, Solvik K, Walker X J, Mack M C and Turetsky M R 2020 Wildfire combustion and
106
carbon stocks in the southern Canadian boreal forest: Implications for a warming world Glob. Chang. Biol. 1–18
Flynn M, Ford J D, Labbe J, Schrott L and Tagalik S 2019 Evaluating the effectiveness of hazard mapping as climate change adaptation for community planning in
degrading permafrost terrain Sustain. Sci. 14 1041–56
Fraser R H, Kokelj S V, Lantz T C, McFarlane-Winchester M, Olthof I and Lacelle D 2018 Climate Sensitivity of High Arctic Permafrost Terrain Demonstrated by Widespread Ice-Wedge Thermokarst on Banks Island Remote Sens. 10
Gibson C M, Chasmer L E, Thompson D K, Quinton W L, Flannigan M D and Olefeldt D 2018 Wildfire as a major driver of recent permafrost thaw in boreal peatlands Nat. Commun. 9 Online: http://dx.doi.org/10.1038/s41467-018-05457-1
Gordon J, Quinton W, Branfireun B A and Olefeldt D 2016 Mercury and methylmercury
biogeochemistry in a thawing permafrost wetland complex, Northwest Territories, Canada Hydrol. Process. 30 3627–38
Jorgenson M T, Shur Y L and Pullman E R 2006 Abrupt increase in permafrost degradation in Arctic Alaska Geophys. Res. Lett. 33
Kasischke E S and Turetsky M R 2006 Recent changes in the fire regime across the North American boreal region - Spatial and temporal patterns of burning across Canada and Alaska Geophys. Res. Lett. 33
Lawrence D M, Koven C D, Swenson S C, Riley W J and Slater A G 2015 Permafrost
thaw and resulting soil moisture changes regulate projected high-latitude CO2 and CH4 emissions Environ. Res. Lett. 10
Lewkowicz A G and Way R G 2019 Extremes of summer climate trigger thousands of thermokarst landslides in a High Arctic environment Nat. Commun. 10
Loisel J, Yu Z, Beilman D W, Camill P, Alm J, Amesbury M J, Anderson D, Andersson S, Bochicchio C, Barber K, Belyea L R, Bunbury J, Chambers F M, Charman D J, De Vleeschouwer F, Fiałkiewicz-Kozieł B, Finkelstein S A, Gałka M, Garneau M, Hammarlund D, Hinchcliffe W, Holmquist J, Hughes P, Jones M C, Klein E S,
Kokfelt U, Korhola A, Kuhry P, Lamarre A, Lamentowicz M, Large D, Lavoie M, MacDonald G, Magnan G, Mäkilä M, Mallon G, Mathijssen P, Mauquoy D, McCarroll J, Moore T R, Nichols J, O’Reilly B, Oksanen P, Packalen M, Peteet D, Richard P J, Robinson S, Ronkainen T, Rundgren M, Sannel A B K, Tarnocai C,
Thom T, Tuittila E-S, Turetsky M, Väliranta M, van der Linden M, van Geel B, van Bellen S, Vitt D, Zhao Y and Zhou W 2014 A database and synthesis of northern peatland soil properties and Holocene carbon and nitrogen accumulation The
107
Holocene 24 1028–42 Online: http://journals.sagepub.com/doi/10.1177/0959683614538073
McGuire A D, Genet H, Lyu Z, Pastick N, Stackpoole S, Birdsey R, D’Amore D, He Y, Rupp T S, Striegl R, Wylie B K, Zhou X, Zhuang Q and Zhu Z 2018 Assessing
historical and projected carbon balance of Alaska: A synthesis of results and policy/management implications Ecol. Appl. 28 1396–412
Mcguire A D, Lawrence D M, Koven C, Clein J S, Burke E and Chen G 2018 Dependence of the evolution of carbon dynamics in the northern permafrost
region on the trajectory of climate change 115 3882–7
Melvin A M, Larsen P, Boehlert B, Neumann J E, Chinowsky P, Espinet X, Martinich J, Baumann M S, Rennels L, Bothner A, Nicolsky D J and Marchenko S S 2017 Climate change damages to Alaska public infrastructure and the economics of
proactive adaptation Proc. Natl. Acad. Sci. 114 E122–31 Online: http://www.pnas.org/lookup/doi/10.1073/pnas.1611056113
Olefeldt D, Goswami S, Grosse G, Hayes D, Hugelius G, Kuhry P, Mcguire A D, Romanovsky V E, Sannel A B K, Schuur E A G and Turetsky M R 2016
Circumpolar distribution and carbon storage of thermokarst landscapes Nat. Commun. 7 1–11 Online: http://dx.doi.org/10.1038/ncomms13043
Pelletier N, Talbot J, Olefeldt D, Turetsky M, Blodau C, Sonnentag O and Quinton W L 2017 Influence of Holocene permafrost aggradation and thaw on the
paleoecology and carbon storage of a peatland complex in northwestern Canada The Holocene 27 1391–405 Online: http://journals.sagepub.com/doi/10.1177/0959683617693899
Pokrovsky O S, Manasypov R M, Kopysov S G, Krickov I V., Shirokova L S, Loiko S V.,
Lim A G, Kolesnichenko L G, Vorobyev S N and Kirpotin S N 2020 Impact of Permafrost Thaw and Climate Warming on Riverine Export Fluxes of Carbon, Nutrients and Metals in Western Siberia Water 12
Quinton W L and Baltzer J L 2013 Changing surface water systems in the discontinuous
permafrost zone: implications for streamflow Publication vol 360, ed Gelfan, A and Yang, D and Gusev, Y and Kunstmann, H pp 85–92
Quinton W L, Chasmer L E and Petrone R M 2011a Permafrost loss and a new approach to the study of subarctic ecosystems in transition Publication vol 346,
ed Yang, D and Marsh, P and Gelfan, A pp 98–102
108
Quinton W L, Hayashi M and Chasmer L E 2011b Permafrost-thaw-induced land-cover change in the Canadian subarctic: Implications for water resources Hydrol. Process. 25 152–8
Quinton W L and Marsh P 1999 A Conceptual Framework for Runoff Generation in a
Permafrost Environment Hydrol. Process. 13 2563–81
Ramsdale J D, Balme M R, Conway S J, Gallagher C, van Gasselt S A, Hauber E, Orgel C, Séjourné A, Skinner J A, Costard F, Johnsson A, Losiak A, Reiss D, Swirad Z M, Kereszturi A, Smith I B and Platz T 2017 Grid-based mapping: A
method for rapidly determining the spatial distributions of small features over very large areas Planet. Space Sci. 140 49–61
Ratajczak Z, Stephen C, Ives A, Kucharik C, Ramiadantsoa T, Stenger M, Williams J, Zhang J and Turner M 2018 Abrupt Change in Ecological Systems.pdf Trends
Ecol. Evol. 33 513–26
Rocha J C, Peterson G D and Biggs R 2015 Regime shifts in the Anthropocene: Drivers, risks, and resilience PLoS One 10 10–2
Rudy A C A, Lamoureux S F, Kokelj S V, Smith I R and England J H 2017 Accelerating
Thermokarst Transforms Ice-Cored Terrain Triggering a Downstream Cascade to the Ocean Geophys. Res. Lett. 44 11080–7
Schaefer K, Lantuit H, Romanovsky V E, Schuur E A G and Witt R 2014 The impact of the permafrost carbon feedback on global climate Environ. Res. Lett. 9
Smith L C, Sheng Y and MacDonald G M 2007 A First Pan-Arctic Assessment of the Influence of Glaciation, Permafrost, Topography and Peatlands on Northern Hemisphere Lake Distribution Permafr. Periglac. Process. 18 201–8
Smith S L, Romanovsky V E, Lewkowicz A G, Burn C R, Allard M, Clow G D,
Yoshikawa K and Throop J 2010 Thermal State of Permafrost in North America: A Contribution to the International Polar Year Permafr. Periglac. Process. 21 117–35
Steedman A E, Lantz T C and Kokelj S V. 2017 Spatio-Temporal Variation in High-
Centre Polygons and Ice-Wedge Melt Ponds, Tuktoyaktuk Coastlands, Northwest Territories Permafr. Periglac. Process. 28 66–78
Tank S E, Striegl R G, McClelland J W and Kokelj S V 2016 Multi-decadal increases in dissolved organic carbon and alkalinity flux from the Mackenzie drainage basin to
the Arctic Ocean Environ. Res. Lett. 11
109
Thomson J A, Burkholder D A, Heithaus M R, Fourqurean J W, Fraser M W, Statton J and Kendrick G A 2015 Extreme temperatures, foundation species, and abrupt ecosystem change: an example from an iconic seagrass ecosystem Glob. Chang. Biol. 21 1463–74
Wang X, Thompson D K, Marshall G A, Tymstra C, Carr R and Flannigan M D 2015 Increasing frequency of extreme fire weather in Canada with climate change Clim. Change 130 573–86
Westerling A 2016 Increasing western US forest wildfire activity: sensitivity to changes
in the timing of spring Philos. Trans. R. Soc. Biol. Sci. 371 Online: http://escholarship.org/reader_feedback.html%0Ahttps://escholarship.org/uc/item/7k41w4h9%0Ahttps://doi.org/10.1098/rstb.2015.0178%0Ahttp://www.escholarship.org/help_copyright.html#reuse%0Ahttp://dx.doi.org/10.1098/rstb.2015.0178
Wright N, Hayashi M and Quinton W L 2009 Spatial and temporal variations in active layer thawing and their implication on runoff generation in peat-covered permafrost terrain Water Resour. Res. 45
Zoltai S C 1993 Cyclic Development of Permafrost in the Peatlands of Northwestern
Canada Arct. Alp. Res. 25 240–6
Zoltai S C and Tarnocai C 1974 Perennially Frozen Peatlands in the Western Arctic and Subarctic of Canada Can. J. Earth Sci. 12 28–43
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6 Conclusion
Permafrost thaw is posed to drive widespread changes in ecosystems as the rates
of thaw increases at unprecedented rates (IPCC 2018). The impacts of permafrost thaw
are widespread and diverse and span impacts to ecosystem processes, services, and
human well-being (Schuur & Mack 2017). Effectively adapting to changing permafrost
conditions will require enhanced understanding an integrated permafrost system that
considers all aspects (both ecological and social) of the permafrost system. I performed
a systematic scoping review to identify the impacts of permafrost thaw and developed a
framework for further investigation into the integrated permafrost system. I highlight the
importance of viewing the permafrost environment through an integrated lens that
recognizes the impacts of permafrost thaw on ecosystem processes, ecosystem
services, and human well-being. When this integrated approach is taken, I argue that
this creates a greater understanding of the permafrost system as a whole and allows for
the identification of new and emerging complex problems caused by the thawing of
permafrost. With these ideas in mind, I make 4 calls to action for permafrost
researchers related to disciplinary focus, knowledge co-production, knowledge sharing
and mobilization, and realignment of funding programs. I provide key steps that can be
taken by funding agencies, institutions, principal investigators and students to support
the mobilization of these calls to action.
I mobilize the calls to action in Chapter 2 where I identified and quantified the extent
to which permafrost thaw impacted land-users in interior Alaska. Here I couple
community-based data collection methodologies (also referred to bottom-up knowledge)
with large-scale remote sensing approaches (referred to as top-down knowledge) to
develop enhanced understanding of the permafrost-land-user system by integrating
these knowledge types. I show that this integrated approach is essential for effective
adaptation planning in northern communities and leads to more holistic understanding
of the system. I show that permafrost thaw accounts for on third to half of all hazards
land-users face and that by taking an integrated approach, we gain an amplified
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understanding the permafrost system and a thematic understanding that allowed me to
frame the results within broader trends and patterns. I argue that this association and
integration add value to large-scale institutional efforts and locally-relevant observations
of environmental change. A key challenge emerged from this study which was related to
the scale of top-down knowledge, with many permafrost vulnerability frameworks being
developed at circumpolar scales.
I tackle the challenge of permafrost vulnerability data at scales not relevant to
communities by conducting and interpreting trends of permafrost thaw using a grid-
based approach to mapping permafrost peatlands in Chapter 3 and 4. Here I mapped
vulnerable permafrost peatlands in 3.75 X 3.75 km grid cells and by doing it at this scale
decrease the predicted area of ‘high or very high vulnerability’ by 90%. This is incredibly
important for community planning as it provides a more focus and targeted
understanding of the landscape and what and where ecosystem services may be at risk
from thawing permafrost. Furthermore, in this study, I show that permafrost thaw in
peatlands across the Northwest Territories is not uniform with peatlands in northern
latitudes remaining climate-protected with relatively little thaw, compared to more
southernly located peatlands which are already experiencing widespread thaw,
particularly at lower elevations. Collectively, the data produced and its interpretation
offers a more scale-appropriate approach to support community adaptation planning
under continued warming and thawing of permafrost.
Taken collectively, the findings of this thesis show the importance of consider
communities and their needs at the forefront of any permafrost related study. When this
is done, not only does an enhanced and enriched understanding of the permafrost
system emerge, but the knowledge and information generated is more easily accessed
and applied by communities and decision makers. Given that the thawing of permafrost
is a natural phenomenon that cannot be easily reversed, community and planning focus
is likely to be on adapting to changing permafrost conditions. This necessarily will
require a holistic understanding of the permafrost system from changes in the
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environment, to the services those environments provide, to the impacts on humans
and society. To support an enhanced understanding of these elements future research
and researchers should seek to orient their programs and their efforts to align with
community identified priorities and locations.
Just as this thesis enhanced our understanding the permafrost it also identifies
several areas for continued exploration. Importantly, many of the findings of this thesis
lend themselves to use by communities to support community planning an adaptation. A
key decision support tool that this thesis does not achieve is an enhanced
understanding of risk and permafrost thaw. Presently the permafrost research
community only considers risk as the predisposition of an area to experiencing thaw.
However, risk is the function of both the probability of a negative event occurring and
the consequence of said negative event. Future work should aim to develop a
framework to be able to understand and assess permafrost risk in this way. Importantly,
this will require a deeper understanding and quantification of the consequence
component of the equation, particularly impacts of permafrost thaw on human-
wellbeing.
In order to be able to develop a permafrost risk framework, I propose conducting
semi-structured interviews with land-users and knowledge holder that focus specifically
on permafrost thaw and subsequent impacts, their response to the impacts, and the
projected long term impacts to their livelihoods from these changes. To complement
this, additional work should be with communities to map important land-based features
and their locations. With this information, future work should aim to combine the
geospatial locations and the perceived impact from thaw. This will inform our
understanding of the consequence’s component of the risk equation. By creating a
framework that incorporates community identified priorities on the land, said framework
can help to unify an understanding of the magnitude of permafrost thaw related impacts
amongst land-users, communities, and government agencies.
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APPENDICES
Supplementary Table 2: Proportion of studies by permafrost thaw related impact
Impact from Permafrost Thaw Proportion of Studies (%)
Type of Study
Terrestrial Carbon Cycling 29.4 Ecosystem Process
Aquatic Carbon Cycling 13.3 Ecosystem Process
Water Chemistry 8.0 Ecosystem Process
Microbial Communities 7.1 Ecosystem Process
Hydrological Flow 6.4 Ecosystem Process
Terrestrial Nutrient Cycling 6.2 Ecosystem Process
Soil and Water Pollutants 4.9 Ecosystem Process
Plant Communities - Composition 4.4 Ecosystem Process
Plant Communities - Productivity 4.2 Ecosystem Process
Aquatic Nutrient Cycling 3.8 Ecosystem Process
Wildlife Distribution 3.3 Ecosystem Service
Hydrological Storage 2.9 Ecosystem Process
Infrastructure Integrity 1.5 Ecosystem Service
Climate Regulation 1.3 Ecosystem Service
Food Security 0.9 Human Well-Being
Cultural Attributes 0.4 Ecosystem Service
Economic Well-Being 0.4 Human Well-Being
Human Health 0.4 Human Well-Being
Aesthetic Pleasurre 0.2 Human Well-Being
Land Access 0.2 Ecosystem Service
Land Stability 0.2 Ecosystem Service
Reliable Housing 0.2 Ecosystem Service
Wildlife Abundance 0.2 Ecosystem Service
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Supplementary Figure 1: Details of the review process according to the Preferred
Reporting Items for Systematic Review and Meta-Analysis (PRISMA) protocol (Arksey
and O’Malley 2005). During identification articles were removed primarily because they
were not related to permafrost or were outside the geographic scope. During the
screening process, articles were mainly removed as they focused on a driver of thaw or
the geophysical conditions of permafrost.
Supplemental 1: Search strings used
(TS=(("permafrost thaw") AND (chang* OR ecosystem service* OR wildlife OR risk OR
communit* OR relocation Or water quality OR water flow OR water storage OR biogeochemistry OR access OR traditional routes OR travel OR food security OR nutrition OR caribou OR fish OR berries OR moose OR economic impact OR health OR security OR hunter OR safety OR hunter safety OR roads OR infrastructure OR
building* OR erosion* OR riverbank erosion OR landslide OR active layer detachment OR thaw slump OR retrogressive thaw slump OR wildlife habitat OR wildlife distribution
116
OR land cover OR forest OR carbon OR methane OR DOC or Mercury OR Nitrogen OR nutrients OR culture OR Soil OR CO2 OR respiration OR primary productivity)))
(TS=(("thermokarst") AND (chang* OR ecosystem service* OR wildlife OR risk OR communit* OR relocation Or water quality OR water flow OR water storage OR
biogeochemistry OR access OR traditional routes OR travel OR food security OR nutrition OR caribou OR fish OR berries OR moose OR economic impact OR health OR security OR hunter OR safety OR hunter safety OR roads OR infrastructure OR building* OR erosion* OR riverbank erosion OR landslide OR active layer detachment
OR thaw slump OR retrogressive thaw slump OR wildlife habitat OR wildlife distribution OR land cover OR forest OR carbon OR methane OR DOC or Mercury OR Nitrogen OR nutrients OR culture OR Soil OR CO2 OR respiration OR primary productivity)))
(TS=(("permafrost degradation") AND (chang* OR ecosystem service* OR wildlife OR
risk OR communit* OR relocation Or water quality OR water flow OR water storage OR biogeochemistry OR access OR traditional routes OR travel OR food security OR nutrition OR caribou OR fish OR berries OR moose OR economic impact OR health OR security OR hunter OR safety OR hunter safety OR roads OR infrastructure OR
building* OR erosion* OR riverbank erosion OR landslide OR active layer detachment OR thaw slump OR retrogressive thaw slump OR wildlife habitat OR wildlife distribution OR land cover OR forest OR carbon OR methane OR DOC or Mercury OR Nitrogen OR nutrients OR culture OR Soil OR CO2 OR respiration OR primary productivity)))
(TS=(("erosion") AND (chang* OR ecosystem service* OR wildlife OR risk OR communit* OR relocation Or water quality OR water flow OR water storage OR biogeochemistry OR access OR traditional routes OR travel OR food security OR nutrition OR caribou OR fish OR berries OR moose OR economic impact OR health OR
security OR hunter OR safety OR hunter safety OR roads OR infrastructure OR building* OR erosion* OR riverbank erosion OR landslide OR active layer detachment OR thaw slump OR retrogressive thaw slump OR wildlife habitat OR wildlife distribution OR land cover OR forest OR carbon OR methane OR DOC or Mercury OR Nitrogen OR
nutrients OR culture OR Soil OR CO2 OR respiration OR primary productivity)))
Supplemental 2: Additional methods
Literature Searching, Screening, and Extraction
Retrieved citations were exported from all databases into a format supported by
Mendeley© referencing software (v1.17.1, Mendeley Ltd. 2016), which served to store,
117
organize, and manage articles. Citations returned with empty publication fields were be
hand searched and replaced by reviewer. The de-duplication function in Mendeley© will
be used to eliminate duplicated citations. We used the search terms: “permafrost thaw”,
“thermokarst”, “erosion” AND a list of descriptor variables that could be impacted by
permafrost thaw (Supplemental 1).
Selected studies had to address an outcome or impact of permafrost thaw on
ecological, social, economic or political systems. Articles that examine the drivers of
permafrost thaw or the thermal and geological properties of permafrost such as
geomorphology and surficial are not included. Other reasons that articles where
excluded included they were simply located in permafrost environments but did not
assess and outcome of thaw, provided a characterization of the landscape (ex. Carbon
stocks, nitrogen pools) but did not assess impacts to these pools from thaw, did a
paleoecological reconstruction and only described permafrost history, provided only a
remote sensing or modeling technique with no statement about an impact of permafrost
thaw, or characterized the biogeochemical environment within describing changes to it
caused by permafrost thaw. Furthermore, during full text screening, studies were also
removed with they only hypothesized about the impacts of permafrost thaw and did not
have qualitative or quantitative data to support the hypothesis.
In total, we included nine study attributes in the data charting form. These
included article title, authors, year published, journal published in, country of study,
study site locations, form of permafrost thaw, outcome of thaw studied, and type of
outcome studied (process, service or societal benefit). Experts working within the
permafrost field were used to help draw topical boundaries.
1
Supplementary Table 1: Complete list of compiled papers and their topics.
Study Number
Lead Author Year Published Article Title
Process, Service,
Benefit
Study Location(s)
Journal
1 Kokelj, Steve 2005 The Influence of Thermokarst Disturbance on the Water Quality of
Small Upland Lakes, Mackenzie Delta Region, Northwest Territories, Canada
Process Canada Journal of Geophysical
Research: Biogeoscience
2 Carrasco,
Jonathan
2006 Modeling physical and biogeochemical
controls over carbon accumulation in a boreal forest soil
Process Canada Biogeosciences
3 Johansson, Torbjörn
2006 Decadal vegetation changes in a northern peatland, greenhouse gas
fluxes and net radiative forcing
Process Sweden Global Change Biology
4 Katamura, Fumitaka
2006 Thermokarst Formation and Vegetation Dynamics Inferred from A
Palynological Study in Central Yakutia, Eastern Siberia, Russia
Process Russia Environmental Research Letters
5 Wickland,
Kimberly
2006 Effects of permafrost melting on CO2
and CH4 exchange of a poorly drained black spruce lowland
Process United
States
AIMS Geosciences
2
6 Yavitt, Joseph 2006 Methanogenesis and Methanogen Diversity in Three Peatland Types of the Discontinuous Permafrost Zone,
Boreal Western Continental Canada
Process Canada Environmental Research Letters
7 Fortier, Daniel 2007 Observation of Rapid Drainage System Development by Thermal Erosion of
Ice Wedges on Bylot Island, Canadian Arctic Archipelago
Process Canada Journal of Cold Region
Engineering
8 Frey, Karen 2007 Geochemistry of west Siberian
streams and their potential response to permafrost degradation
Process All Biogeochemistry
9 Frey, Karen 2007 Impacts of climate warming and
permafrost thaw on the riverine transport of nitrogen and phosphorus to the Kara Sea
Process Russia Environmental
Microbiology Reports
10 Lopez, CM 2007 Epigenetic salt accumulation and
water movement in the active layer of central Yakutia in eastern Siberia
Process Russia FEMS
Microbiology Ecology
11 Myers-Smith,
Isla
2007 Influence of disturbance on carbon
exchange in a permafrost collapse and adjacent burned forest
Process United
States
Geophysical
Research Letters
3
12 Prater, James 2007 Variation in methane production pathways associated with permafrost decomposition in collapse scar bogs of
Alberta, Canada
Process Canada Journal of Geophysical Research:
Biogeosciences
13 Rohrs-Richey, Jennifer
2007 Effects of local changes in active layer and soil climate on seasonal foliar
nitrogen concentrations of three boreal forest shrubs
Process United States
Biogeosciences
14 Rohrs-Richey,
Jennifer
2007 Effects of local changes in active layer
and soil climate on seasonal foliar nitrogen concentrations of three boreal forest shrubs
Process United
States
Biogeochemistry
15 Schuur, Edward
2007 Plant Species Composition and Productivity following Permafrost Thaw and Thermokarst in Alaskan Tundra
Process United States
Global Change Biology
16 Ström, Lena 2007 Below ground carbon turnover and greenhouse gas exchanges in a sub-arctic wetland
Process Sweden Polar Biology
17 Turetsky, Merritt
2007 The disappearance of relict permafrost in boreal north America: Effects on peatland carbon storage and fluxes
Process United States
Journal of Applied Ecology
4
18 Uhlírová, E. 2007 Quality and potential biodegradability of soil organic matter preserved in permafrost of Siberian tussock tundra
Process Russia Journal of Ecology
19 Walters, Katey 2007 Methane bubbling from northern lakes: present and future contributions to the global methane
budget
Process United States, Russia
Permafrost and Periglacial Processes
20 Walters, Katie 2007 Thermokarst Lakes as a Source of
Atmospheric CH4 During the Last Deglaciation
Process Canada, United
States, Sweden,
Russia
Arctic Science
21 Walvoord, Michelle
2007 Increased groundwater to stream discharge from permafrost thawing in the Yukon River basin: Potential impacts on lateral export of carbon
and nitrogen
Process United States
Journal of Geophysical Research
22 Blodau, Christian
2008 A snapshot of CO2 and CH4 evolution in a thermokarst pond near Igarka,
northern Siberia
Process Russia Geophysical Research Letters
5
23 Bowden, W.B. 2008 Sediment and nutrient delivery from thermokarst features in the foothills of the North Slope, Alaska: Potential
impacts on headwater stream ecosystems
Process United States
Journal of Geophysical Research
24 Flessa, Heiner 2008 Landscape controls of CH4 fluxes in a
catchment of the forest tundra ecotone in northern Siberia
Process Russia Ecosystems
25 Guggenberger,
Georg
2008 Storage and mobility of black carbon
in permafrost soils of the forest tundra ecotone in Northern Siberia
Process Russia Permafrost and
Periglacial Processes
26 Klaminder,
Jonatan
2008 An explorative study of mercury
export from a thawing palsa mire
Process Sweden Journal of
Geophysical Research
27 Lawrence, David
2008 Sensitivity of a model projection of near-surface permafrost degradation
to soil column depth and representation of soil organic matter
Process United States
New Phytologist
28 Turetsky,
Merritt
2008 Short-term response of methane
fluxes and methanogen activity to water table and soil warming manipulations in an Alaskan peatland
Process Canada Journal of
Environmental Radioactivity
6
29 Walter Anthony,
Katey
2008 Methane production and bubble emissions from arctic lakes: Isotopic implications for source pathways and
ages
Process Modelling Biogeosciences
30 Alfaro, Marolo 2009 Case Study of Degrading Permafrost beneath a Road Embankment
Service Canada Arctic Science
31 Balcarczk, Kelly
2009 Stream dissolved organic matter bioavailability and composition in watersheds underlain with
discontinuous permafrost
Process United States
Journal of Geophysical Research
32 Bense, V.F 2009 Evolution of shallow groundwater flow systems in areas of degrading
permafrost
Process Canada, United
States
Journal of Geophysical
Research
33 Breton, Jullie 2009 Limnological properties of permafrost thaw ponds in northeastern Canada
Process Canada Soil Biology & Biochemisty
34 Desyatkin,
Alexey
2009 CH4 emission from different stages of thermokarst formation in Central Yakutia, East Siberia
Process Russia Canadian Journal
of Fisheries and Aquatic Sciences
35 Frey, Karen 2009 Impacts of permafrost degradation on arctic river biogeochemistry
Process Russia Journal of
Geophysical Research
7
36 Kokelj, Steve 2009 The Impacts of Thawing Permafrost on the Chemistry of Lakes across the Subarctic Boreal-Tundra Transition,
Mackenzie Delta Region, Canada
Process Canada Dendrochronolgia
37 Lantz, Trevor 2009 Relative impacts of disturbance and temperature: persistent changes in
microenvironment and vegetation in retrogressive thaw slumps
Process Canada Ecosystems
38 Mazéas,
Olivier
2009 Impact of terrestrial carbon input on
methane emissions from an Alaskan Arctic lake
Process United
States
Journal of
Geophysical Research Biogeosciences
39 Muskett, Reginald
2009 Groundwater storage changes in arctic permafrost watersheds from GRACE and in situ measurements
Process Canada, Russia
Aquatic Sciences
40 Roehm,
Charlotte
2009 Bioavailability of terrestrial organic
carbon to lake bacteria: The case of a degrading subarctic permafrost mire complex
Process Sweden Ecohydrology
41 Schuur, Edward
2009 The effect of permafrost thaw on old carbon release and net carbon exchange from tundra
Process United States
The Royal Society B
8
42 Vogel, Jason 2009 Response of CO2 exchange in a tussock tundra ecosystem to permafrost thaw and thermokarst
development
Process United States
Ecology
43 Ye, Baisheng 2009 Variation of hydrological regime with permafrost coverage over Lena Basin
in Siberia
Process Russia Functional Ecology
44 Camill, Philip 2010 Early life history transitions and recruitment of Picea mariana in
thawed boreal permafrost peatlands
Process Canada Frontiers in Microbiology
45 Czimczik, Claudia
2010 Radiocarbon Content of CO2 Respired from High Arctic Tundra in Northwest
Greenland
Process Denmark (Greenland)
Environmental Research Letters
46 Karlsson, Jan 2010 Quantifying the relative importance of lake emissions in the carbon budget of a subarctic catchment
Process Sweden Journal of Geophysical Research
47 Keller, Katy 2010 Stream geochemistry as an indicator of increasing permafrost thaw depth in an arctic watershed
Process United States
Arctic Science
48 Laurion, Isabelle
2010 Variability in greenhouse gas emissions from permafrost thaw ponds
Process Canada Biogeosciences
9
49 Lee, Hanna 2010 Soil CO2 production in upland tundra where permafrost is thawing
Process United States
Journal of Geophysical Research:
Biogeosciences
50 Mesquita, Patricia
2010 Effects of retrogressive permafrost thaw slumping on sediment chemistry
and submerged macrophytes in Arctic tundra lakes
Process Canada European Journal of Soil Biology
51 Molau, Ulf 2010 Long-term impacts of observed and
induced climate change on tussock tundra near its southern limit in northern Sweden
Process Sweden Arctic, Antarctic
and Alpine Research
52 Bouchard, Frédéric
2011 Sedimentology and geochemistry of thermokarst ponds in discontinuous permafrost, subarctic Quebec, Canada
Process Canada Hydrological Processes
53 Coolen, Marco 2011 Bioavailability of soil organic matter
and microbial community dynamics upon permafrost thaw
Process United
States
Global Change
Biology
54 Fortier,
Richard
2011 Impacts of permafrost degradation on
a road embankment at Umiujaq in Nunavik (Quebec), Canada
Service Canada Landslides
10
55 Hugelius, Gustaf
2011 High‐resolution mapping of ecosystem carbon storage and potential effects of permafrost thaw in periglacial terrain,
European Russian Arctic
Process Russia Boreal Environment Research
56 Huissteden, J 2011 Methane emissions from permafrost thaw lakes limited by lake drainage
Process Russia Biogeosciences
57 Koven, Charles 2011 Permafrost carbon-climate feedbacks accelerate global warming
Process United States
Ecography
58 Lee, Hanna 2011 A spatially explicit analysis to
extrapolate carbon fluxes in upland tundra where permafrost is thawing
Process United
States
Nature
Geoscience
59 Michaelson,
G.J
2011 Methane and carbon dioxide content
in eroding permafrost soils along the Beaufort Sea coast, Alaska
Process United
States
Hydrological
Processes
60 Natali, Susan 2011 Effects of experimental warming of air, soil and permafrost on carbon balance
in Alaskan tundra
Process United States
Environmental Microbiology
61 O'Donnell, Jonathan
2011 The effect of fire and permafrost interactions on soil carbon
accumulation in an upland black spruce ecosystem of interior Alaska: implications for post-thaw carbon loss
Process United States
Frontiers in Microbiology
11
62 Pokrovsky, O 2011 Effect of permafrost thawing on organic carbon and trace element colloidal speciation in the thermokarst
lakes of western Siberia
Process Russia Nature Climate Change
63 Quinton, William
2011 Permafrost-thaw-induced land-cover change in the Canadian subarctic:
implications for water resources
Process Canada Proceeding in the National Academy
of Science
64 Revich, Boris 2011 Thawing of permafrost may disturb historic cattle burial grounds in East
Siberia
Benefit Russia Sedimentary Geology
65 Roach, Jennifer
2011 Mechanisms influencing changes in lake area in Alaskan boreal forest
Service United States
Anthropocene
66 Belshe, E.F 2012 Incorporating spatial heterogeneity created by permafrost thaw into a landscape carbon estimate
Process United States
Frontiers of Microbiology
67 Bense, V.H 2012 Permafrost degradation as a control on hydrogeological regime shifts in a warming climate
Process United States
Scientific Reports
68 Brosius, L.S 2012 Using the deuterium isotope composition of permafrost meltwater to constrain thermokarst lake
Process United
States
PLOS One
12
contributions to atmospheric CH4 during the last deglaciation
69 Chasmer, Laura
2012 C02 Exchanges within Zones of Rapid Conversion from Permafrost Plateau to Bog and Fen Land Cover Types
Process Canada Arctic, Antarctic and Alpine Research
70 Deison, Ramin 2012 Spatial and Temporal Assessment of Mercury and Organic Matter in Thermokarst Affected Lakes of the
Mackenzie Delta Uplands, NT, Canada
Process Canada Soil Biology and Biochemistry
71 Harms, Tamara
2012 Thaw depth determines reaction and transport of inorganic nitrogen in
valley bottom permafrost soils
Process United States
Environmental Microbiology
72 Hollesen, Jørgen
2012 The Future Preservation of a Permanently Frozen Kitchen Midden in
Western Greenland
Service Denmark (Greenland)
Environmental Science &
Technology
73 Hugelius, Gustaf
2012 Mapping the degree of decomposition and thaw remobilization potential of soil organic matter in discontinuous
permafrost terrain
Process Russia Biogeosciences
13
74 Jones, Miriam 2012 Peat accumulation in drained thermokarst lake basins in continuous, ice-rich permafrost, northern Seward
Peninsula, Alaska
Process United States
Molecular Ecology
75 Karlsson, Johanna Mård
2012 Thermokarst lake, hydrological flow and water balance indicators of
permafrost change in Western Siberia
Process Russia Biogeosciences
76 Kessler, M. 2012 Simulating the decadal- to millennial-scale dynamics of morphology and
sequestered carbon mobilization of two thermokarst lakes in NW Alaska
Process United States
Limnology and Oceanography
77 Keuper, Frida 2012 A frozen feast: thawing permafrost
increases plant-available nitrogen in subarctic peatlands
Process Sweden Arctic Science
78 Lewis, Ted 2012 Hydrochemical and sedimentary responses of paired High Arctic
watersheds to unusual climate and permafrost disturbance, Cape Bounty, Melville Island, Canada
Process Canada Soil Science and Plant Nutrition
79 O'Donnell, Jonathan
2012 Dissolved organic matter composition of winter flow in the Yukon River basin: Implications of permafrost thaw
and increased groundwater discharge
Process United States
Journal of Contemporary Water Research &
Education
14
80 O'Donnell, Jonathan
2012 The Effects of Permafrost Thaw on Soil Hydrologic, Thermal, and Carbon Dynamics in an Alaskan Peatland
Process United States
Biogeosciences
81 Olefeldt, David 2012 Effects of permafrost and hydrology on the composition and transport of dissolved organic carbon in a subarctic
peatland complex
Process Sweden Permafrost and Periglacial Processes
82 Pries, Caitlin 2012 Holocene Carbon Stocks and Carbon Accumulation Rates Altered in Soils
Undergoing Permafrost Thaw
Process United States
Geophysical Research Letters
83 Thompson, Megan
2012 Shifts in Plankton, Nutrient and Light Relationships in Small Tundra Lakes
Caused by Localized Permafrost Thaw
Process Canada Chemical Geology
84 Trucco, Christian
2012 Seven-year trends of CO2 exchange in a tundra ecosystem affected by long-term permafrost thaw
Process United States
Environmental Science and Technology
85 Walvoord, Michelle
2012 Influence of permafrost distribution on groundwater flow in the context of climate-driven permafrost thaw:
Example from Yukon Flats Basin, Alaska, United States
Process United States
Environmental Science and Technology
15
86 Wheeler, Helen
2012 Arctic ground squirrels Urocitellus parryii as drivers and indicators of
change in northern ecosystems
Service Canada, United States
Journal of Geophysical Research:
Biogeosciences
87 Anderson, Lesleigh
2013 Controls on recent Alaskan lake changes identified from water
isotopes and remote sensing
Process United States
Nature Climate Change
88 Biskaborn, Boris
2013 Late Holocene thermokarst variability inferred from diatoms in a lake
sediment record from the Lena Delta, Siberian Arctic
Process Russia Nature Climate Change
89 Callaghan,
Terry
2013 Ecosystem change and stability over
multiple decades in the Swedish subarctic: complex processes and multiple drivers
Process Sweden Nature
Microbiology
90 Cory, Rose 2013 Surface exposure to sunlight
stimulates CO2 release from permafrost soil carbon in the Arctic
Process United
States
Soil Biology and
Biochemistry
91 Douglas,
Thomas
2013 Hydrogeochemistry of seasonal flow
regimes in the Chena River, a subarctic watershed draining discontinuous permafrost in interior Alaska (USA)
Process United
States
Biogeochemistry
16
92 Elberling, Bo 2013 Long-term CO2 production following
permafrost thaw
Process Denmark (Greenland)
Soil Biology and Biochemistry
93 Euskirchen,
Eugénie
2013 An estimated cost of lost climate
regulation services caused by thawing of the Arctic cryosphere
Process Russia Environmental
Research Letters
94 Forsström,
Laura
2013 Responses of microbial food web to
increased allochthonous DOM in an oligotrophic subarctic lake
Service Finland Journal of
Geophysical Research: Biogeosciences
95 Frampton,
Andrew
2013 Permafrost degradation and
subsurface-flow changes caused by surface warming trends
Process Sweden Ecological
Applications
96 Gao, Xiang 2013 Permafrost degradation and methane: low risk of biogeochemical climate- warming feedback
Service United
States
Journal of
Geophysical Research: Biogeosciences
97 Jolivel, Maxime
2013 Thermokarst and export of sediment and organic carbon in the Sheldrake River watershed, Nunavik, Canada
Process Canada Geophysical Reserch Letters
98 Jorgenson, Torre
2013 Reorganization of vegetation, hydrology and soil carbon after
Process United States
Ecohydrology
17
permafrost degradation across heterogeneous boreal landscapes
99 Klein, Eric 2013 Recent increase in peatland carbon
accumulation in a thermokarst lake basin in southwestern Alaska
Process United
States
Limnology and
Oceanography
100 Knoblauch,
Christian
2013 Predicting long-term carbon
mineralization and trace gas production from thawing permafrost of Northeast Siberia
Process Russia Journal of Ecology
101 Kokelj, S.V 2013 Thawing of massive ground ice in
mega slumps drives increases in stream sediment and solute flux across a range of watershed scales
Process Canada Global Change
Biology
102 Maldonado, Julie
2013 The impact of climate change on tribal communities in the US: displacement, relocation, and human rights
Service United States
Aquatic Microbial Ecology
103 Malone, Laura 2013 Impacts of hillslope thaw slumps on the geochemistry of permafrost catchments (Stony Creek watershed,
NWT, Canada)
Process Canada Permafrost and Periglacial Processes
18
104 McKenzie, Jeffrey
2013 Permafrost thaw in a nested groundwater-flow system
Process United States
Canadian Geotechnical Journal
105 Patankar, Rajit 2013 Permafrost-driven differences in habitat quality determine plant response to gall-inducing mite
herbivory
Process Canada Science of the Total Environment
106 Pokrovsky, O.S 2013 Impact of western Siberia heat wave 2012 on greenhouse gases and trace
metal concentration in thaw lakes of discontinuous permafrost zone
Process Russia Hydrogeology Journal
107 Pries, Caitlin 2013 Moisture drives surface decomposition in thawing tundra
Process United
States
Water Resources
Research
108 Pries, Caitlin 2013 Thawing permafrost increases old soil and autotrophic respiration in tundra: Partitioning ecosystem respiration
using 13C and 14C
Process United States
Hydrological Processes
109 Quinton, William
2013 Changing surface water systems in the discontinuous permafrost zone:
implications for streamflow
Process Canada Journal of Geophysical
Research
19
110 Quinton, William
2013 The active-layer hydrology of a peat plateau with thawing permafrost (Scotty Creek, Canada)
Process Canada Water Resources Research
111 Rossi, Paul-Georges
2013 Distribution and identity of Bacteria in subarctic permafrost thaw ponds
Process Canada The Cryosphere
112 Shirokova, L.S 2013 Biogeochemistry of organic carbon,
CO2, CH4, and trace elements in thermokarst water bodies in discontinuous permafrost zones of
Western Siberia
Process Russia Biogeosciences
113 Tape, Ken 2013 Inundation, sedimentation, and subsidence creates goose habitat
along the Arctic coast of Alaska
Service United States
Journal of Geophysical
Research: Biogeosciences
114 Thienpoint, Joshua
2013 Biological responses to permafrost thaw slumping in Canadian Arctic lakes
Service Canada Environmental Research Letters
115 Wellman, Tristan
2013 Impacts of climate, lake size, and supra- and sub-permafrost groundwater flow on lake-talik
evolution, Yukon Flats, Alaska (USA)
Process United States
Nature Geoscience
116 Williams, Tyler 2013 Linear disturbances on discontinuous
permafrost: implications for thaw-
Process Canada European Journal of Soil Science
20
induced changes to land cover and drainage patterns
117 Abbott,
Benjamin
2014 Elevated dissolved organic carbon
biodegradability from thawing and collapsing permafrost
Process United
States
Global Change
Biology
118 Allan, J 2014 Methanogen community composition
and rates of methane consumption in Canadian High Arctic permafrost soils
Process Canada Hydrological
Processes
119 Baltzer, Jennifer
2014 Forests on thawing permafrost: fragmentation, edge effects, and net
forest loss
Process Canada Environmental Science &
Technology
120 Beamish, Alison
2014 Short-term impacts of active layer detachments on carbon exchange in a
High Arctic ecosystem, Cape Bounty, Nunavut, Canada
Process Canada Hydrological Processes
121 Biasi, Christina 2014 Microbial Respiration in Arctic Upland
and Peat Soils as a Source of Atmospheric Carbon Dioxide
Process Russia Biogeochemistry
122 Cable, Jessica 2014 Permafrost thaw affects boreal
deciduous plant transpiration through increased soil water, deeper thaw, and warmer soils
Process United
States
Global Change
Biology
21
123 Chen, Min 2014 Temporal and spatial pattern of thermokarst lake area changes at Yukon Flats, Alaska
Process United States
Global Change Biology
124 Connon, Ryan 2014 Changing hydrologic connectivity due to permafrost thaw in the lower Liard River valley, NWT, Canada
Process Canada Biogeochemistry
125 Deng, J. 2014 Assessing effects of permafrost thaw on C fluxes based on multiyear modeling across a permafrost thaw
gradient at Stordalen, Sweden
Process Sweden Environmental Research Letters
126 Euskirchen, Eugine
2014 Differential response of carbon fluxes to climate in three peatland
ecosystems that vary in the presence and stability of permafrost
Process United States
Environmental Research Letters
127 Fedorov, A.N 2014 Estimating the water balance of a
thermokarst lake in the middle of the Lena River basin, eastern Siberia
Process Russia Journal of Geophysical
Research: Biogeosciences
128 Gaglioti,
Benjamin
2014 Radiocarbon age-offsets in an arctic
lake reveal the long-term response of permafrost carbon to climate change
Process United
States
Geophysical
Research Letters
22
129 Harms, Tamara
2014 Thermo-erosion gullies increase nitrogen available for hydrologic export
Process United States
Global Change Biology
130 Hayes, Daniel 2014 The impacts of recent permafrost thaw on land–atmosphere greenhouse gas exchange
Process United States
Global Change Biology
131 Hodgkins, Suzanne
2014 Changes in peat chemistry associated with permafrost thaw increase greenhouse gas production
Process Sweden Global Change Biology
132 Iijima, Yoshihiro
2014 Sap flow changes in relation to permafrost degradation under increasing precipitation in an eastern
Siberian larch forest
Service Russia Biogeosciences
133 Jensen, A.E 2014 Variations in soil carbon dioxide efflux across a thaw slump chronosequence in northwestern Alaska
Process United States
Polar Research
134 Johnston, Carmel
2014 Effect of permafrost thaw on CO2 and CH4 exchange in a western Alaska peatland chronosequence
Process United States
Global Change Biology
135 Karlsson, Johanna Mård
2014 Temporal Behavior of Lake Size-Distribution in a Thawing Permafrost Landscape in Northwestern Siberia
Process Russia Nature Letter
23
136 Klapstein, Sara 2014 Controls on methane released through ebullition in peatlands affected by permafrost degradation
Process United States
Geochimica et Cosmochimica Acta
137 Krüger, J.P 2014 Degradation changes stable carbon isotope depth profiles in palsa peatlands
Process Sweden Proceedings of the National Academy of Sciences
138 Li, Jianwei 2014 Modeling permafrost thaw and ecosystem carbon cycle under annual and seasonal warming at an Arctic
tundra site in Alaska
Process United States
Biogeochemistry
139 Manasypov, R.M
2014 Thermokarst lake waters across the permafrost zones of western Siberia
Process Russia Archaemetry
140 McCalley, Carmody
2014 Methane dynamics regulated by microbial community response to permafrost thaw
Process Sweden Antiquity Publications
141 Mondav, Rhiannon
2014
Discovery of a novel methanogen
prevalent in thawing permafrost
Process Sweden Conservation and Management of Archaeological Sites
142 Moquin, Paul 2014 Responses of benthic invertebrate
communities to shoreline
Service Canada Fundamental and Applied Limnology
24
retrogressive thaw slumps in Arctic upland lakes
143 Natali, Susan 2014 Permafrost degradation stimulates
carbon loss from experimentally warmed tundra
Process United
States
Journal of
Geophysical Research
144 O'Donnell,
Jonathan
2014 Using dissolved organic matter age
and composition to detect permafrost thaw in boreal watersheds of interior Alaska
Process United
States
Journal of
Geophysical Research
145 Olefeldt, David 2014 Permafrost conditions in peatlands
regulate magnitude, timing, and chemical composition of catchment dissolved organic carbon export
Process Sweden Nature Climate
Change
146 Pizano, Camila 2014 Effects of thermo-erosional disturbance on surface soil carbon and nitrogen dynamics in upland arctic
tundra
Process United States
Ecohydrology
147 Schadel, Christina
2014 Circumpolar assessment of permafrost C quality and its vulnerability over
time using long-term incubation data
Process All International Journal of
Climatology
25
148 Stephani, Eva 2014 A geosystems approach to permafrost investigations for engineering applications, an example from a road
stabilization experiment, Beaver Creek, Yukon, Canada
Service Canada Arctic, Antarctic and Alpine Research
149 Walter
Anthony, Kaie
2014 A shift of thermokarst lakes from
carbon sources to sinks during the Holocene epoch
Process Russia Polar Science
150 Abbott,
Benjamin
2015 Patterns and persistence of hydrologic
carbon and nutrient export from collapsing upland permafrost
Process United
States
Geoderma
Regional
151 Abbott,
Benjamin
2015 Permafrost collapse alters soil carbon
stocks, respiration, CH4, and N2O in upland tundra
Process Expert
Opinion
Environmental
Research Letters
152 Alfredsson, Hanna
2015 Amorphous silica pools in permafrost soils of the Central Canadian Arctic
and the potential impact of climate change
Process Canada Hydrological Processes
153 Andresen,
Christian
2015 Disappearing Arctic tundra ponds:
Fine-scale analysis of surface hydrology in drained thaw lake basins over a 65year period (1948–2013)
Process United
States
Global Change
Biology
26
154 Arp, CD 2015 Distribution and biophysical processes of beaded streams in Arctic permafrost landscapes
Process United States
Environmental Research Letters
155 Bryukhanova, Marina
2015 The response of 13C, 18O and cell anatomy of Larix gmelinii tree rings to differing soil active layer depths
Process Russia Journal of Geophysical Research
156 Coleman, Kristen
2015 tracking the impacts of recent warming and thaw of permafrost peatlands on aquatic ecosystems: a
multi-proxy approach using remote sensing and lake sediments
Process Canada Arctic Science
157 Coolen, Marco 2015 The transcriptional response of
microbial communities in thawing Alaskan permafrost soils
Process United
States
Permafrost and
Periglacial Processes
158 Crevecoeur, Sophie
2015 Bacterial community structure across environmental gradients in permafrost
thaw ponds: methanotroph-rich ecosystems
Process Canada Journal of Geophysical
Research
159 Deng, Jie 2015 Shifts of tundra bacterial and archaeal
communities along a permafrost thaw gradient in Alaska
Process United
States
Global Change
Biology
27
160 Deshpande, Bethany
2015 Oxygen dynamics in permafrost thaw lakes: Anaerobic bioreactors in the Canadian subarctic
Process Canada Environmental Research Letters
161 Dornblaser, Mark
2015 Switching predominance of organic versus inorganic carbon exports from an intermediate-size subarctic
watershed
Process United States
Scientific Reports
162 Ernakovich, Jessica
2015 Permafrost microbial community traits and functional diversity indicate low
activity at in situ thaw temperatures
Process United States
Journal of Geophysical
Research
163 Frampton, Andrew
2015 Impact of degrading permafrost on subsurface solute transport pathways
and travel times
Process United States
Journal of Hydrology
164 Fritz, M 2015 Dissolved organic carbon (DOC) in Arctic ground ice
Process Canada, United States,
Russia
Journal of Hydrology
165 Gentsch, N 2015 Properties and bioavailability of particulate and mineral-associated
organic matter in Arctic permafrost soils, Lower Kolyma Region, Russia
Process Russia Remore Sensing
28
166 Gibson, J.J 2015 Runoff to boreal lakes linked to land cover, watershed morphology and permafrost thaw: a 9-year isotope
mass balance assessment
Process Canada Arctic, Antarctic and Alpine Research
167 Heikoop, Jeffrey
2015 Isotopic identification of soil and permafrost nitrate sources in an Arctic
tundra ecosystem
Process United States
Chemical Geology
168 Heslop, J.K 2015 Thermokarst lake methanogenesis along a complete talik profile
Process United States
Global Change Biology
169 Hicks Pries, Caitlin
2015 Decadal warming causes a consistent and persistent shift from heterotrophic to autotrophic
respiration in contrasting permafrost ecosystems
Process United States,
Sweden
Journal of Geophysical Research
170 Hilton, Robert 2015 Erosion of organic carbon in the Arctic as a geological carbon dioxide sink
Process Canada Global Change Biology
171 Hodgkins, Suzanne
2015 Soil incubations reproduce field methane dynamics in a subarctic wetland
Process Sweden Global Change Biology
172 Jones, Benjamin
2015 Observing a Catastrophic Thermokarst Lake Drainage in Northern Alaska
Process United States
Journal of Microbiology
29
173 Kao-Kniffin, J 2015 Archaeal and bacterial communities across a chronosequence of drained lake basins in arctic alaska
Process Canada Science of the Total Environment
174 Karlsson, Johanna
2015 Hydro-climatic and lake change patterns in Arctic permafrost and non-
permafrost areas
Process Canada, United States,
Sweden, Russia
Jounral of Geophysical Research
175 Kim, Yongwon 2015 Effect of thaw depth on fluxes of CO2
and CH4 in manipulated Arctic coastal tundra of Barrow, Alaska
Process United
States
Journal of
Geophysical Research Biogeosciences
176 Koven, Charles 2015 Permafrost carbon−climate feedback is sensitive to deep soil carbon
decomposability but not deep soil nitrogen dynamics
Process United States
Palaeogeography, Palaeoclimatology, Palaeoecology
177 Lantz, Trevor 2015 Changes in lake area in response to thermokarst processes and climate in
Old Crow Flats, Yukon
Process Canada Global Change Biology
178 Larouche, J.R. 2015 The role of watershed characteristics, permafrost thaw, and wildfire on
dissolved organic carbon
Process United States
Nature Climate Change
30
biodegradability and water chemistry in Arctic headwater streams
179 Lawrence, D.M
2015 Permafrost thaw and resulting soil moisture changes regulate projected
high-latitude CO2 and CH4 emissions
Process United States
Journal of Geophysical Research:
Biogeosciences
180 Lewis, Tyler 2015 Pronounced chemical response of
Subarctic lakes to climate-driven losses in surface area
Process United States
Journal of Geophysical
Research: Earth Surface
181 MacMillan,
Gwyneth
2015 High Methylmercury in Arctic and
Subarctic Ponds is Related to Nutrient Levels in the Warming Eastern Canadian Arctic
Process Canada Permafrost and
Periglacial Processes
182 Manasypov, R.M
2015 Seasonal dynamics of organic carbon and metals in thermokarst lakes from the discontinuous permafrost zone of western Siberia
Process Russia Permafrost and Periglacial Processes
183 Mann, Paul 2015 Utilization of ancient permafrost carbon in headwaters of Arctic fluvial networks
Process Russia Proceedings in the National Academy of Science
31
184 Martinez-Cruz, K
2015 Geographic and seasonal variation of dissolved methane and aerobic methane oxidation in Alaskan lakes
Process United States
Proceedings in the National Academy of Science
185 Matheus Carnevali, P.B
2015 Methane sources in arctic thermokarst lake sediments on the North Slope of Alaska
Process United States
Nature Communications
186 Monquin, Paul 2015 Effects of permafrost degradation on water and sediment quality and heterotrophic bacterial production of
Arctic tundra lakes: An experimental approach
Process Canada Biogeosciences
187 Natali, Susan 2015 Permafrost thaw and soil moisture
driving CO2 and CH4 release from upland tundra
Process United
States
Biogeosciences
188 Natali, Susan 2015 Permafrost thaw and soil moisture
driving CO2 and CH4 release from upland tundra
Process United
States
Scientific Reports
189 Newman, B.D. 2015 Microtopographic and depth controls on active layer chemistry in Arctic
polygonal ground
Process United States
Arctic Science
32
190 Overduin, Piere Paul
2015 Methane oxidation following submarine permafrost degradation: Measurements from a central Laptev
Sea shelf borehole
Process Russia Arctic Science
191 Patankar, Rajit 2015 Sap flow responses to seasonal thaw and permafrost degradation in a
subarctic boreal peatland
Process Canada Environmental Research Letters
192 Reyes, Franciso
2015 Rapid nutrient release from permafrost thaw in arctic aquatic
ecosystems
Process United States
Journal of Geophysical
Research: Biogeosciences
193 Roach,
Jennifer
2015 Climate-induced lake drying causes
heterogeneous reductions in waterfowl species richness
Process United
States
Global Change
Biology
194 Roiha, T 2015 Carbon dynamics in highly heterotrophic subarctic thaw ponds
Process Canada Arctic
195 Sepulveda-Jauregui, A
2015 Methane and carbon dioxide emissions from 40 lakes along a north–south latitudinal transect in Alaska
Process United States
Biogeosciences
196 Spencer, Robert
2015 Detecting the signature of permafrost thaw in Arctic rivers
Process Russia Limnology and Oceanography
33
197 Streletskiy, Dmitry
2015 Permafrost hydrology in changing climatic conditions: seasonal variability of stable isotope composition in rivers
in discontinuous permafrost
Process Russia Environmental Research Letters
198 Tan, Zeli 2015 Arctic lakes are continuous methane sources to the atmosphere under
warming conditions
Process
Journal of Geophysical
Research
199 Thompson, M.S
2015 Size and characteristics of the DOC pool in near-surface subarctic mire
permafrost as a potential source for nearby freshwaters
Process Sweden Journal of Geophysical
Research
200 von Deimling,
T
2015 Observation-based modelling of
permafrost carbon fluxes with accounting for deep carbon deposits and thermokarst activity
Process United
States
Global Change
Biology
201 Abbott,
Benjamin
2016 Biomass offsets little or none of
permafrost carbon release from soils, streams, and wildfire: an expert assessment
Process United
States
Geochimica et
Cosmochimica Acta
202 Addison, Priscilla
2016 Utilizing Vegetation Indices as a Proxy to Characterize the Stability of a Railway Embankment in a Permafrost
Region
Service Canada Freshwater Biology
34
203 Becker, Michael
2016 Ground ice melt in the high Arctic leads to greater ecological heterogeneity
Process Canada Hydrological Processes
204 Becker, Michael
2016 Sixty-year legacy of human impacts on a high Arctic ecosystem
Process Canada Global Change Biology
205 Bégin,
Paschale
2016 Permafrost thaw lakes and ponds as
habitats for abundant rotifer populations
Service Canada Oecologia
206 Bond-
Lamberty, Ben
2016 Temperature and moisture effects on
greenhouse gas emissions from deep active-layer boreal soils
Process United
States
Plant Soil
207 Bracho, Rosvel 2016 Temperature sensitivity of organic
matter decomposition of permafrost-region soils during laboratory incubations
Process United
States
Journal of
Geophysical Research: Biogeosciences
208 Buckeridge,
Kate
2016 Vegetation Leachate During Arctic
Thaw Enhances Soil Microbial Phosphorus
Process United
States
Nature Letters
209 Chin, Krista 2016 Permafrost thaw and intense
thermokarst activity decreases abundance of stream benthic macroinvertebrates
Process Canada Biogeosciences
35
210 Comte, J 2016 Co-occurrence patterns in aquatic bacterial communities across changing
permafrost landscapes
Process Canada Journal of Geophysical Research:
Biogeosciences
211 Comte, Jérôme
2016 Microbial biogeography of permafrost thaw ponds across the changing
northern landscape
Process Canada Chemical Geology
212 Coulombe, Olivier
2016 Coupling of sedimentological and limnological dynamics in subarctic
thermokarst ponds in Northern Quebec (Canada) on an interannual basis
Process Canada Hydrological Processes
213 Crevecoeur, Sophie
2016 Environmental selection of planktonic methanogens in permafrost thaw ponds
Process Canada PLOS One
214 Deshpande,
Bethany
2016 Bacterial production in subarctic
peatland lakes enriched by thawing permafrost
Process Canada Environmental
Science and Technology
215 Domine,
Florent
2016 The growth of shrubs on high Arctic
tundra at Bylot Island: impact on snow physical properties and permafrost thermal regime
Process Canada Quaternary
Science Reviews
36
216 Dore, Guy 2016 Adaptation Methods for Transportation Infrastructure Built on Degrading Permafrost
Service All Climatic Change
217 Eickmeyer, David
2016 Interactions of polychlorinated biphenyls and organochlorine pesticides with sedimentary organic
matter of retrogressive thaw slump-affected lakes in the tundra uplands adjacent to the Mackenzie Delta, NT,
Canada
Process Canada Arctic, Antarctic and Alpine Research
218 Finger, Rebecca
2016 Effects of permafrost thaw on nitrogen availability and plant–soil interactions
in a boreal Alaskan lowland
Process United States
Chemical Geology
219 Girard, Catherine
2016 Photodemethylation of Methylmercury in Eastern Canadian Arctic Thaw Pond and Lake Ecosystems
Process Canada Biogeosciences
220 Gordon, J 2016 Mercury and methylmercury biogeochemistry in a thawing permafrost wetland complex,
Northwest Territories, Canada
Process Canada The Cryosphere
221 Grewer, David 2016 Redistribution of soil organic matter by permafrost disturbance in the
Canadian High Arctic
Process Canada Nature Climate Change
37
222 Helbig, M 2016 Permafrost thaw and wildfire: Equally important drivers of boreal tree cover changes in the Taiga Plains, Canada
Process Canada Arctic Science
223 Helbig, Manuel
2016 Regional atmospheric cooling and wetting effect of permafrost thaw-induced boreal forest loss
Service Canada Biogeosciences
224 Hodgkins, Suzanne
2016 Elemental composition and optical properties reveal changes in dissolved organic matter along a permafrost
thaw chronosequence in a subarctic peatland
Process Sweden Geobiology
225 Houben,
Adam
2016 The impacts of permafrost thaw
slump events on limnological variables in upland tundra lakes, Mackenzie Delta region
Process Canada Limnology and
Oceanography
226 Iijima,
Yoshihiro
2016 Enhancement of Arctic storm activity
in relation to permafrost degradation in eastern Siberia
Process Russia Arctic Science
227 Istomin, Kirill 2016 Permafrost and indigenous land use in
the northern Urals: Komi and Nenets reindeer husbandry
Benefit Russia Global Change
Biology
38
228 Jepsen, Steven 2016 Effect of permafrost thaw on the dynamics of lakes recharged by ice-jam floods: case study of Yukon Flats,
Alaska
Process Canada Geophysical Research Letteres
229 Jolivel, Maxime
2016 Impact of permafrost thaw on the turbidity regime of a subarctic river:
the Sheldrake River, Nunavik, Quebec
Process Canada Nature
230 Keuper, Frida 2016 Experimentally increased nutrient availability at the permafrost thaw
front selectively enhances biomass production of deep-rooting subarctic peatland species
Process Sweden Hydrogeology Journal
231 Kim, Hye Min 2016 Vertical distribution of bacterial community is associated with the degree of soil organic matter decomposition in the active layer of
moist acidic tundra
Process United States
Proceedings in the National Academy of Science
232 Lewis, Tyler 2016 Trophic dynamics of shrinking Subarctic lakes: naturally eutrophic
waters impart resilience to rising nutrient and major ion concentrations
Process United States
Freshwater Biology
39
233 Matveev, Alex 2016 High methane emissions from thermokarst lakes in subarctic peatlands
Process Canada Journal of Geophysical Research
234 Melvin, April 2016 Climate change damages to Alaska public infrastructure and the economics of proactive adaptation
Service United States
Plant Ecology & Diversity
235 Neumann, Rebecca
2016 Modeling CH4 and CO2 cycling using porewater stable isotopes in a thermokarst bog in Interior Alaska:
results from three conceptual reaction networks
Process United States
Nature Communication
236 Nicklen, E.F 2016 Local site conditions drive climate–
growth responses of Picea mariana and Picea glauca in interior Alaska
Process United
States
Environmental
Microbiology
237 O'Donnell, Johnathan
2016 Dissolved organic matter composition of Arctic rivers: Linking permafrost and
parent material to riverine carbon
Process United States
Limnology and Oceanography
238 Penton, C. Ryan
2016 NifH-Harboring Bacterial Community Composition across an Alaskan
Permafrost Thaw Gradient
Process United States
The ISME Journal
40
239 Perreault, Naïm
2016 Thermo-erosion gullies boost the transition from wet to mesic tundra vegetation
Process Canada Freshwater Science
240 Pokrovsky, Oleg
2016 Organic and organo-mineral colloids in discontinuous permafrost zone
Process Russia Arctic, Antarctic and Alpine Research
241 Pries, Caitlin 2016 Old soil carbon losses increase with ecosystem respiration in experimentally thawed tundra
Process United States
Environmental Research Letters
242 Przytulska, A 2016 Phototrophic pigment diversity and picophytoplankton in permafrost thaw lakes
Service Canada Limnology and Oceanography
243 Schadel, Christina
2016 Potential carbon emissions dominated by carbon dioxide from thawed permafrost soils
Process United States
Journal of Geophysical Research
244 Sniderhan,
Anastasia
2016 Growth dynamics of black spruce
(Picea mariana) in a rapidly thawing discontinuous permafrost peatland
Process Canada Journal of
Hydrology
245 Stapel, J.G. 2016 Microbial lipid signatures and
substrate potential of organic matter in permafrost deposits: Implications for future greenhouse gas production
Process Russia Journal of
Geophysical Research: Biogeosciences
41
246 Stiegler, Christian
2016 Tundra permafrost thaw causes significant shifts in energy partitioning
Service Sweden Global Change Biology
247 Takakura,
Hiroki
2016 Limits of pastoral adaptation to
permafrost regions caused by climate change among the Sakha people in the middle basin of Lena River
Service Russia Ecology
248 Tank, Suzanne 2016 Multi-decadal increases in dissolved organic carbon and alkalinity flux from the Mackenzie drainage basin to the
Arctic Ocean
Process Canada Journal of Geophysical Research:
Biogeosciences
249 Toohey, R.C 2016 Multidecadal increases in the Yukon River Basin of chemical fluxes as
indicators of changing flowpaths, groundwater, and permafrost
Process United States
Biogeochemistry
250 Treat, Claire 2016 Longer thaw seasons increase nitrogen availability for leaching during fall in
tundra soils
Process United States
Geophysical Research Letters
251 van der Holk, Henk-Jan
2016 Potential Arctic tundra vegetation shifts in response to changing
temperature, precipitation and permafrost thaw
Process United States
Ecosphere
42
252 Vaughn, Lydia 2016 Isotopic insights into methane production, oxidation, and emissions in Arctic polygon tundra
Process United States
Permafrost and Periglacial Processes
253 Walter Anthony,
Katey
2016 Methane emissions proportional to permafrost carbon thawed in Arctic
lakes since the 1950s
Process Canada, United States,
Russia
Global Biogeochemical Cycles
254 Weiss, Niels 2016 Thermokarst dynamics and soil organic matter characteristics controlling
initial carbon release from permafrost soils in the Siberian Yedoma region
Process Russia Global Biogeochemical
Cycles
255 Wertebach,
T.M
2016 Relationships between Vegetation
Succession, Pore Water Chemistry and CH4 and CO2 Production in a Transitional Mire of Western Siberia
Process Russia Journal of
Geophysical Research: Biogeosciences
256 Wolter,
Juliane
2016 Vegetation composition and shrub
extent on the Yukon coast, Canada, are strongly linked to ice-wedge polygon degradation
Process United
States
Global Change
Biology
257 Xue, Kai 2016 Tundra soil carbon is vulnerable to rapid microbial decomposition under climate warming
Process United States
Ecosystems
43
258 Yang, Ziming 2016 Warming increases methylmercury production in an Arctic soil
Process United States
Journal of Geophysical Research
259 Young-Robertson,
Jessica
2016 Thawing seasonal ground ice: An important water source for boreal forest plants in Interior Alaska
Process United States
Global Change Biology
260 Beermann, Fabian
2017 Permafrost Thaw and Liberation of Inorganic Nitrogen in Eastern Siberia
Process Russia Global Change Biology
261 Carey, Joanna 2017 Biogenic silica accumulation varies
across tussock tundra plant functional type
Process United
States
Journal of
Geophysical Research: Biogeosciences
262 Cassidy, Alison 2017 Impacts of active retrogressive thaw slumps on vegetation, soil, and net ecosystem exchange of carbon dioxide in the Canadian High Arctic1
Process Canada The Cryosphere
263 Celis, Gerado 2017 Tundra is a consistent source of CO2 at a site with progressive permafrost thaw during 6 years of chamber and
eddy covariance measurements
Process United States
The Cryosphere
264 Chapman, Eric 2017 Soil microbial community composition
is correlated to soil carbon processing
Process United States
Journal of Ecology
44
along a boreal wetland formation gradient
265 Cooper, Mark 2017 Limited contribution of permafrost
carbon to methane release from thawing peatlands
Process Canada Trees
266 Crate, Susan 2017 Permafrost livelihoods: A
transdisciplinary review and analysis of thermokarst-based systems of indigenous land use
Benefit Russia The Holocene
267 Crevecoeur,
Sophie
2017 Diversity and potential activity of
methanotrophs in high methane-emitting permafrost thaw ponds
Process Canada Frontiers in
Microbiology
268 Deshpande,
Bethany
2017 Oxygen depletion in subarctic
peatland thaw lakes
Process Canada Biogeosciences
269 Diaz, Krystalle 2017 Searching for Antibiotic Resistance Genes in a Pristine Arctic Wetland
Service Sweden Environmental Research Letters
270 Ernakovich, Jessica
2017 Redox and temperature-sensitive changes in microbial communities and soil chemistry dictate greenhouse gas
loss from thawed permafrost
Process United States
Biogeosciences
45
271 Euskirchen, Eugénie
2017 Interannual and Seasonal Patterns of Carbon Dioxide, Water, and Energy Fluxes From Ecotonal and
Thermokarst-Impacted Ecosystems on Carbon-Rich Permafrost Soils in Northeastern Siberia
Service
Biogeosciences
272 Evans, Sarah 2017 Contrasting hydrogeologic responses to warming in permafrost and seasonally frozen ground hillslopes
Process United States
Geochimica et Cosmochimica Acta
273 Fouche, Julien 2017 Diurnal evolution of the temperature sensitivity of CO2 efflux in permafrost soils under control and warm
conditions
Process Canada Environmental Science and Technology
274 Fuchs, Matthias
2017 Carbon and nitrogen pools in thermokarst-affected permafrost landscapes in Arctic Siberia
Process Russia Environmental Research Letters
275 Helbig, Manuel
2017 Direct and indirect climate change effects on carbon dioxide fluxes in a thawing boreal forest–wetland
landscape
Process Canada Global Biogeochemical Cycles
276 Helbig, Manuel
2017 The positive net radiative greenhouse
gas forcing of increasing methane
Service Canada Ecosystems
46
emissions from a thawing boreal forest-wetland landscape
277 Heslop,
Joanne
2017 Variable respiration rates of incubated
permafrost soil extracts from the Kolyma River lowlands, north-east Siberia
Process Russia Journal of
Geophysical Research
278 Hollesen, J 2017 The Impact of Climate Change on an Archaeological Site in the Arctic
Service Denmark (Greenland)
Global Change Biology
279 Inglese. Cara 2017 Examination of soil microbial communities after permafrost thaw
subsequent to an active layer detachment in the High Arctic
Process Canada Nature Climate Change
280 Jones, Miriam 2017 Rapid carbon loss and slow recovery
following permafrost thaw in boreal peatlands
Process United
States
forests
281 Lafrenière,
Melissa
2017 Active layer slope disturbances affect
seasonality and composition of dissolved nitrogen export from High Arctic headwater catchments
Process Canada Biogeosciences
47
282 Lamhonwah, Daniel
2017 Multi-year impacts of permafrost disturbance and thermal perturbation on High Arctic stream chemistry
Process Canada Freshwater Biology
283 Lantz, Trevor 2017 Vegetation Succession and Environmental Conditions following Catastrophic Lake Drainage in Old
Crow Flats, Yukon
Process Canada Hydrological Processes
284 Lehn, Gregory 2017 Constraining seasonal active layer dynamics and chemical weathering
reactions occurring in North Slope Alaskan watersheds with major ion and isotope
Process United States
Hydrogeology Journal
285 Li, Bingxi 2017
Thaw pond development and initial vegetation succession in experimental
plots at a Siberian lowland tundra site
Process Russia Cold and Mountain Region Hydrological Systems Under
Climate Change
286 Littlefair, Cara 2017 Retrogressive thaw slumps temper dissolved organic carbon delivery to streams of the Peel Plateau, NWT, Canada
Process Canada Biogeosciences
48
287 Loiko, Sergey 2017 Abrupt permafrost collapse enhances organic carbon, CO2, nutrient and metal release into surface waters
Process Russia Biogeosciences
288 Mauritz, Marguerite
2017 Nonlinear CO2 flux response to 7 years of experimentally induced permafrost thaw
Process Canada Science of the Total Environment
289 Mondav, Rhiannon
2017 Microbial network, phylogenetic diversity and community membership in the active layer across a permafrost
thaw gradient
Process Sweden Global Health Action
290 Narancic, Biljana
2017 Landscape-gradient assessment of thermokarst lake hydrology using
water isotope tracers
Process Canada Arctic, Antarctic and Alpine
Research
291 Obu, J 2017 Effect of Terrain Characteristics on Soil Organic Carbon and Total Nitrogen Stocks in Soils of Herschel Island,
Western Canadian Arctic
Process Canada Geosciences Journal
292 Pelletier, Nicolas
2017 Influence of Holocene permafrost aggradation and thaw on the
paleoecology and carbon storage of a peatland complex in northwestern Canada
Process Canada Geosciences Journal
49
293 Przytulska, Anna
2017 Increased risk of cyanobacterial blooms in northern high-latitude lakes through climate warming and
phosphorus enrichment
Process Canada Global Change Biology
294 Raudina, Tatiana
2017 Dissolved organic carbon and major and trace elements in peat porewater
of sporadic, discontinuous, and continuous permafrost zones of western Siberia
Process Russia Landscape Ecology
295 Roberts, K.E 2017 Climate and permafrost effects on the chemistry and ecosystems of High Arctic Lakes
Process Canada Scientific Reports
296 Rudy, Ashley 2017 Accelerating Thermokarst Transforms Ice-Cored Terrain Triggering a Downstream Cascade to the Ocean
Process Canada Journal of Geophysical Research
297 Salvadó, Joan 2017 Release of Black Carbon From Thawing
Permafrost Estimated by Sequestration Fluxes in the East Siberian Arctic Shelf Recipient
Process Russia Canadian Journal
of Forest Research
298 Selvam, B 2017 Degradation potentials of dissolved organic carbon (DOC) from thawed permafrost peat
Process Finland Canadian Journal of Forest Research
50
299 Stegen, James 2017 Soil respiration across a permafrost transition zone: spatial structure and environmental correlates
Process United States
Biogeosciences
300 Tanski, George 2017 Transformation of terrestrial organic matter along thermokarst-affected permafrost coasts in the Arctic
Process Canada Aquatic Microbial Ecology
301 Voigt, Carolina 2017 Increased nitrous oxide emissions from Arctic peatlands after permafrost thaw
Process Finland Geophysical Research Letters
302 Wang, Peng 2017 Depth-based differentiation in nitrogen uptake between graminoids and shrubs in an Arctic tundra plant
community
Process Russia Journal of Geophysical Research:
Biogeosciences
303 Wang, Peter 2017 Above- and below-ground responses of four tundra plant functional types to deep soil heating and surface soil
fertilization
Process Norway Global Biogeochemical Cycles
304 Wang, Zheng 2017 Comparison of plant litter and peat decomposition changes with
permafrost thaw in a subarctic peatland
Process Canada Global Change Biology
51
305 Wilson, R.M. 2017 Greenhouse gas balance over thaw-freeze cycles in discontinuous zone permafrost
Process Canada Nature Climate Change
306 Wurzbacher, Christian
2017 Poorly known microbial taxa dominate the microbiome of permafrost thaw ponds
Process Canada Environmental Research Letters
307 Zhang, Xiaowen
2017 Importance of lateral flux and its percolation depth on organic carbon export in Arctic tundra soil:
Implications from a soil leaching experiment
Process United States
Geophysical Research Letters
308 Ala-ahod, P 2018 Permafrost and lakes control river
isotope composition across a boreal Arctic transect in the Western Siberian lowlands
Process Russia Ecosystems
309 Alyshuler,
Ianina
2018 Denitrifiers, nitrogen-fixing bacteria
and N2O soil gas flux in high Arctic ice-wedge polygon cryosols
Process Canada Nature Letters
310 Blume-Werry,
Gesche
2018 Dwelling in the deep – strongly
increased root growth and rooting depth enhance plant interactions with thawing permafrost soil
Process Sweden Scientific Reports
52
311 Bond, Mattheq
2018 Permafrost thaw and implications for the fate and transport of tritium in the T Canadian north
Process Canada Biogeosciences
312 Bouchard, Frederic
2018 Periphytic diatom community structure in thermokarst ecosystems of Nunavik (Quebec, Canada)
Service Canada Philosophical Transactions A
313 Burke, S.A 2018 Long‐Term Measurements of Methane Ebullition From Thaw Ponds
Process Sweden Biogeochemistry
314 Burke, S.M. 2018 Patterns and controls of mercury
accumulation in sediments from three thermokarst lakes on the Arctic Coastal Plain of Alaska
Process United
States
The ISME Journal
315 Carnevali, Paula
2018 Distinct Microbial Assemblage Structure and Archaeal Diversity in Sediments of Arctic Thermokarst Lakes Differing in Methane Sources
Process United States
Journal of Geophysical Research: Biogeosciences
316 Carpino, Olivia 2018 Climate change and permafrost thaw-induced boreal forest loss in northwestern Canada
Process Canada Geophysical Research Letters
317 Castro-Morales, Karel
2018 Year-round simulated methane emissions from a permafrost ecosystem in Northeast Siberia
Process Russia Environmental Science and Technology
53
318 Coe, Jeffrey 2018 Increasing rock-avalanche size and mobility in Glacier Bay National Park and Preserve, Alaska detected from
1984 to 2016 Landsat imagery
Process United States
Journal of Geophysical Research:
Biogeosciences
319 Comyn-Platt, Edward
2018 Carbon budgets for 1.5 and 2 °C targets lowered by natural wetland
and permafrost feedbacks
Process Modelling Biogeosciences
320 Dao, Thao 2018 Fate of carbohydrates and lignin in north-east Siberian permafrost soils
Process Russia Biogeosciences
321 de Jong, Anniek
2018 Increases in temperature and nutrient availability positively affect methane-cycling microorganisms in Arctic
thermokarst lake sediments
Process United States
Cold Regions Science and Technology
322 Drake, Travis 2018 Increasing Alkalinity Export from Large Russian Arctic Rivers
Process Russia Tellus B
323 Drake, Travis 2018 The Ephemeral Signature of
Permafrost Carbon in an Arctic Fluvial Network
Process Russia Geosciences
Journal
324 Elder, Clayton 2018 Greenhouse gas emissions from
diverse Arctic Alaskan lakes are dominated by young carbon
Process United
States
Environmental
Research Letters
54
325 Emerson, Joanne
2018 Host-linked soil viral ecology along a permafrost thaw gradient
Process Sweden Soil Biology & Biochemistry
326 Estop-
Aragones, Cristian
2018 Limited release of previously-frozen C
and increased new peat formation after thaw in permafrost peatlands
Process Canada Polar Science
327 Estop-
Aragones, Cristian
2018 Respiration of aged soil carbon during
fall in permafrost peatlands enhanced by active layer deepening following wildfire but limited following
thermokarst
Process Canada Environmental
Research Letters
328 Fernadez, Leyden
2018 Non-cyanobacterial diazotrophs dominate nitrogen-fixing communities
in permafrost thaw ponds
Process Canada Environmental Research Letters
329 Gasser, T 2018 Path-dependent reductions in CO2 emission budgets caused by permafrost carbon release
Process Modelling Science of the Total Environment
330 Gentsch, Norman
2018 Temperature response of permafrost soil carbon is attenuated by mineral protection
Process Russia Environmental Research Letters
55
331 Haynes, KM 2018 Permafrost thaw induced drying of wetlands at Scotty Creek, NWT,
Canada
Process Canada Journal of Geophysical Research:
Biogeosciences
332 Hollesen, Jørgen
2018 Climate change and the deteriorating archaeological and environmental
archives of the Arctic
Service All Freshwater Biology
333 Iwasaki, Shinya
2018 Carbon stock estimation and changes associated with thermokarst activity,
forest disturbance, and land use changes in Eastern Siberia
Process Russia Arctic, Antarctic and Alpine
Research
334 Kendrick,
Michael
2018 Linking permafrost thaw to shifting
biogeochemistry and food web resources in an arctic river
Process United
States
Arctic
335 Knoblauch, Christian
2018 Methane production as key to the greenhouse gas budget of thawing
permafrost
Process Russia Geophysical Research Letters
336 Koch, JC 2018 Ice Wedge Degradation and Stabilization Impact Water Budgets
and Nutrient Cycling in Arctic Trough Ponds
Process United States
Environmental Research Letters
56
337 Kramshøj, Magnus
2018 Biogenic volatile release from permafrost thaw is determined by the soil microbial sink
Process Denmark (Greenland)
American Society for Microbiology
338 Krickov, IV 2018 Riverine particulate C and N generated at the permafrost thaw front: case study of western Siberian rivers across
a 1700 km latitudinal transect
Process Russia Journal of Geophysical Research
339 Kuhn, McKenzie
2018 Emissions from thaw ponds largely offset the carbon sink of northern
permafrost wetlands
Process Sweden Polar Biology
340 Lamontagne-Hallé, Pierrick
2018 Changing groundwater discharge
dynamics in permafrost regions
Process Modelling Global Change Biology
341 Levenstein,
Brianna
2018 Sediment inputs from retrogressive
thaw slumps drive algal biomass accumulation but not decomposition in Arctic streams, NWT
Process Canada Journal of
Geophysical Research
342 Lindgren, Amelie
2018 Extensive loss of past permafrost carbon but a net accumulation into present-day soils
Process Modelling Soil Biology and Biochemistry
343 Littlefair, Cara 2018 Biodegradability of Thermokarst Carbon in a Till-Associated, Glacial
Process Canada Biogeosciences
57
Margin Landscape: The Case of the Peel Plateau, NWT, Canada
344 Loranty,
Michael
2018 Understory vegetation mediates
permafrost active layer dynamics and carbon dioxide fluxes in open-canopy larch forests of northeastern Siberia
Process Russia Remore Sensing
345 Magnan, Gabriel
2018 Impact of the Little Ice Age cooling and 20th century climate change on peatland vegetation dynamics in central and northern Alberta using a
multi-proxy approach and high-resolution peat chronologies
Process Canada Global Change Biology
346 Malhotra, Avni 2018 Post-thaw variability in litter
decomposition best explained by microtopography at an ice-rich permafrost peatland
Process Sweden Journal of
Geophysical Research
347 Martin, Abra 2018 Ice wedge degradation and CO2 and CH4 emissions in the Tuktoyaktuk Coastlands, Northwest Territories
Process Canada Proceedings of the National Academy of Science
348 Matveev, Alex 2018 Methane and carbon dioxide emissions from thermokarst lakes on mineral soils
Process Canada Biogeosciences
58
349 Monteux, Sylvain
2018 Long-term in situ permafrost thaw effects on bacterial communities and potential aerobic respiration
Process Sweden Nature
350 Morison, Matthew
2018 Climate-induced changes in nutrient transformations across landscape units in a thermokarst subarctic
peatland
Process Canada Journal of Geophysical Research
351 Mutschlecner, Audrey
2018 Regional and intra-annual stability of dissolved organic matter composition
and biolability in high-latitude Alaskan rivers
Process United States
Nature Geoscience
352 Olson, C 2018 Mercury in Active-Layer Tundra Soils
of Alaska: Concentrations, Pools, Origins, and Spatial Distribution
Process United
States
Nature
Communications
353 Parazoo, Nicholas
2018 Detecting the permafrost carbon feedback: talik formation and
increased cold-season respiration as precursors to sink-to-source transitions
Process
Philosophical Transactions of
The Royal Society
354 Parazoo, Nicholas
2018 Detecting the permafrost carbon feedback: talik formation and increased cold-season respiration as
Process Modelling Science
59
precursors to sink-to-source transitions
355 Pokrovsky, Oleg
2018 Dissolved Organic Matter Controls Seasonal and Spatial Selenium Concentration Variability in Thaw
Lakes across a Permafrost Gradient
Process Russia Geophysical Research Letters
356 Polishchuk, YM
2018 Minor contribution of small thaw ponds to the pools of carbon and
methane in the inland waters of the permafrost-affected part of the Western Siberian Lowland
Process Russia Water Resources Research
357 Prokushkin, Anatoly
2018 Permafrost Regime Affects the Nutritional Status and Productivity of Larches in Central Siberia
Process Russia Biogeosciences
358 Ramage, Justine
2018 Increasing coastal slump activity impacts the release of sediment and organic carbon into the Arctic Ocean
Process Canada Environmental Science and Technology
359 Raudina, TV 2018 Permafrost thaw and climate warming
may decrease the CO2, carbon, and metal concentration in peat soil waters of the Western Siberia Lowland
Process Russia Environmental
Science and Technology
60
360 Ro, Hee-Myong
2018 Interactive effect of soil moisture and temperature regimes on the dynamics of soil organic carbon decomposition
in a subarctic tundra soil
Process United States
Journal of Vegetation Science
361 Ro, Hee-Myong
2018 Interactive effect of soil moisture and temperature regimes on the dynamics
of soil organic carbon decomposition in a subarctic tundra soil
Process United States
Journal of Ecology
362 Salmon, Verity 2018 Adding Depth to Our Understanding of
Nitrogen Dynamics in Permafrost Soils
Process United
States
Plant Soil
363 Schadel, Christina
2018 Divergent patterns of experimental and model-derived permafrost
ecosystem carbon dynamics in response to Arctic warming
Process All Limnology and Oceanography
364 Schuster, Paul 2018 Permafrost Stores a Globally Significant Amount of Mercury
Process United States
Sedimentary Geology
365 Shakhova, Natalia
2018 The East Siberian Arctic Shelf: towards further assessment of permafrost-related methane fluxes and role of sea
ice
Process Russia Soil Biology & Biochemistry
366 Singleton, Caitlin
2018 Methanotrophy across a natural permafrost thaw environment
Process Sweden Hydrogeology Journal
61
367 St. Pierre, Kyra 2018 Unprecedented Increases in Total and Methyl Mercury Concentrations Downstream of Retrogressive Thaw
Slumps in the Western Canadian Arctic
Process Canada Wetlands
368 Stapel, Janina 2018 Substrate potential of last interglacial to Holocene permafrost organic
matter for future microbial greenhouse gas production
Process Russia Mammal Reviews
369 Streletskaya,
Irina
2018 Methane Content in Ground Ice and
Sediments of the Kara Sea Coast
Process Russia Journal of
Geophysical Research
370 Taylor, MA 2018 Methane Efflux Measured by Eddy
Covariance in Alaskan Upland Tundra Undergoing Permafrost Degradation
Process United
States
Environmental
Research Letters
371 Trubl, Gareth 2018 Soil Viruses Are Underexplored Players in Ecosystem Carbon Processing
Process Sweden Environmental Research Letters
372 Tsuyuzaki, Shiro
2018 Tundra fire alters vegetation patterns more than the resultant thermokarst
Process United States
Journal of Geophysical Research:
Biogeosciences
373 van der Sluijs, Jurjen
2018 Permafrost Terrain Dynamics and
Infrastructure Impacts Revealed by
Service Canada Polar Research
62
UAV Photogrammetry and Thermal Imaging
374 Walter
Anthony, Katey
2018 21st-century modeled permafrost
carbon emissions accelerated by abrupt thaw beneath lakes
Process Russia Nature
375 Walz, Josefine 2018 Greenhouse gas production in
degrading ice-rich permafrost deposits in northeastern Siberia
Process Russia Journal of
Geophysical Research: Biogeosciences
376 Wang, Jun-
Jian
2018 Differences in Riverine and Pond
Water Dissolved Organic Matter Composition and Sources in Canadian High Arctic Watersheds Affected by
Active Layer Detachments
Process Canada International
Society of Microbial Ecology
377 Wang, Jun-Jian
2018 Differences in Riverine and Pond Water Dissolved Organic Matter
Composition and Sources in Canadian High Arctic Watersheds Affected by Active Layer Detachments
Process Canada Nature Climate Change
378 Wauthy, Maxime
2018 Increasing dominance of terrigenous organic matter in circumpolar freshwaters due to permafrost thaw
Process United States, Russia
Environmental Pollution
63
379 Weiss, Niels 2018 Characterization of labile organic matter in Pleistocene permafrost (NE Siberia), using Thermally assisted
Hydrolysis and Methylation (THM-GC- MS)
Process Russia Geomicrobiology Journal
380 Wild, Birgit 2018 Amino acid production exceeds plant nitrogen demand in Siberian tundra
Process Russia Journal of
Geophysical Research
381 Woodcroft,
Ben
2018 Genome-centric view of carbon
processing in thawing permafrost
Process Sweden Ecohydrology
382 Wu, Yuxin 2018 Depth-Resolved Physicochemical Characteristics of Active Layer and
Permafrost Soils in an Arctic Polygonal Tundra Region
Process United States
Global Change Biology
383 Yuan, Mengting
2018 Microbial functional diversity covaries with permafrost thaw-induced
environmental heterogeneity in tundra soil
Process
Science of the Total Environment
384 Zakharova,
Elena
2018 Recent dynamics of hydro-ecosystems
in thermokarst depressions in Central Siberia from satellite and in situ observations: Importance for
agriculture and human life
Benefit Russia Science of the
Total Environment
64
385 Zakharova, Elena
2018 Recent dynamics of hydro-ecosystems in thermokarst depressions in Central Siberia from satellite and in situ
observations: Importance for agriculture and human life
Service Russia Journal of Geophysical Research:
Biogeosciences
386 Zipper, Samuel 2018 Groundwater Controls on Postfire Permafrost Thaw: Water and Energy Balance Effects
Process United
States
Journal of
Geophysical Research: Earth Surface
387 Zolkos, Scott 2018 Mineral Weathering and the Permafrost Carbon-Climate Feedback
Process Canada Geophysical Research Letters