sea level change and coastal hazards in washington
TRANSCRIPT
Bobbak TalebiDepartment of Ecology
Sea Level Change and Coastal Hazards in Washington
Sea Level Change in Washington
Lara Whitely BinderClimate Impacts GroupUniversity of Washington
For More Details…
National Research Council – April 2012IPCC 2013, WG1, Chapter 13 Mote et al. 2008
Future Greenhouse Gas Scenarios
• The previous scenarios have close analogues in the newer scenarios
• In both sets of scenarios, the high end is a “business as usual” scenario (RCP 8.5, SRES A1FI)
• The newer scenarios include an aggressive mitigation scenario (RCP 2.6)
• All scenarios result in similar warming until about mid-‐century.
• Greenhouse gas scenarios are consistent with recent global emissions.
What Do We Know About Global Sea Level Rise?
Sea level has been rising. “Virtually certain” that the rate of global sea level rise has increased over the last two centuries.
IPCC 2013, Figure SPM.3
1901-2010:
+0.06 in/year
(+7.5 inches total)
1993-2010:
+0.13 in/year
(a trend or natural
variability?)
Global Mean SLR Projections
Range of
projected rise for
2100, relative to
1986-2005:
+11 to +38 in.
RCP 2.6: +17 in.
(range: 11-24 in.)
RCP8.5: +29 in.
(range: 21-38 in.)
Figure adapted from IPCC 2013,
Technical Summary for Policy Makers
Solid lines= median value
Dashed lines = likely ranges for RCP4.5 and RCP6.0
Shading = likely ranges for RCP2.6 and RCP8.5
Why is SLR not one number?
Assumptions about future greenhouse gas emissions matter. Different levels of greenhouse gas emissions result in a range of projections for temperature, thermal expansion, etc.
Van Vuuren et al. 2011: http://emf.stanford.edu/files/docs/340/Moss_10.1007-s10584-011-0148-z.pdf
Regional Sea Level CHANGEObserved changes and projections
Photo source: http://www.sequim-real-estate-blog.com/water-
views/sequim-waterfront-2/
Sea level change at any given location and point in time is determined by many factors
NRC 2012
(+)
(+ or -) (+ or -)
(not
incl.)
(-)(+)
(+)
Rates for vertical
land movement
are highly
variable
Red = uplift
Blue = subsidence
Major Contributing
Factors:
Plate tectonics
Soil compaction
Figure source: NRC 2012
Observed TrendsSeattle
Sea level rise of about +8 inches for 1898-2006
(equivalent to a change of +0.68 feet in 100 years)
Source: NOAA Tides and Currents
Observed TrendsNeah Bay
Sea level fall between 1934 and 2006 (equivalent to a change
of -0.53 feet, or -6.4 inches, in 100 years)
Source: NOAA Tides and Currents
Washington State Sea Level Rise (Mote et al. 2008)
Medium (w/range) estimates of sea level rise in Washington for 2100:
.
NW Olympic Peninsula:
+2” (-9 to +35”)
Central/Southern Coast:
+11” (+2 to +43”)
Puget Sound:
+13” (+6 to +50”)
NRC 2012 vs. Mote et al. 2008
Figure source: Climate Impacts Group
NRC 2012 vs. Mote et al. 2008
Figure source: Climate Impacts Group
Bottom line: both provide similar ranges and a good scientific foundation for planning, although differences in vertical land movement may be important in other locations.
“The” number will depend on…
• The expected time horizon of the decision being made (e.g., 20 years vs. 100 years),
• The ability to adapt the decision over time,
• Available alternatives,
• Risk tolerance, and
• Cost
among other factors…
Alki Beach, West Seattle
Photo by Hugh Shipman, WA Dept of Ecology
What Does 2 Feet of SLR Look Like?
Alki Beach, West Seattle, January 21, 2010
Photo by Hugh Shipman, WA Dept. of Ecology
Near-term Challenges of SLR
Sea level rise increases
storm surge and the risk
of:
• flooding,
• erosion,
• habitat loss
These impacts will
affect coastal areas
long before
permanent inundation.
Puget Sound Shorelines
Coastal Shorelines
Erosion
Landslides
Flooding
Heather McCartney, MUK
Storm Surge
Why is this important to consider?
Populations
Buildings
Infrastructure
Natural Resources
Historic Resources
Cultural Resources
Economic Resources
Contaminated Lands
Parks
What concerns do you have about sea level rise?
We already do this work
Regional efforts
Climate Change Preparedness Plan for the North Olympic Peninsula
• Diminishing snowpack
• Shifts in precipitation
• Sea level rise
• Extended warm temperatures
• Ocean acidification
Local efforts
Design efforts
You are not alone
• More support and energy from the public up to the federal government
• Many local governments are interested in taking action
• Building a community of practice
