terrestrial ecosystem response to climate change
DESCRIPTION
Terrestrial Ecosystem Response to Climate Change. Global Change and Effects on Terrestrial Ecosystem. Introduction Temperature, precipitation, latitude and altitude all determine distribution of major terrestrial ecosystems (biomes). - PowerPoint PPT PresentationTRANSCRIPT
Terrestrial Ecosystem Terrestrial Ecosystem Response to Climate Response to Climate
ChangeChange
Global Change and Effects on Terrestrial EcosystemIntroduction Temperature, precipitation, latitude and altitude all
determine distribution of major terrestrial ecosystems (biomes).
Plants found within the different biomes are influenced by soil type, water shed conditions and amount of sun.
Specific combinations of temperatures and precipitation ensure the survival and thriving of plants within a given environment (known as Climate space).
Terrestrial Ecosystems are an…• Integral part of global carbon system• Plants take in and store carbon dioxide from the atmosphere through photosynthesis• Below ground microbes decompose organic matter and release organic carbon back into the
atmosphere
Cycle shows how nature’s sources of CO2 are self regulating – that which is released will be used again – Anthropogenic carbon not part of natures cycle – is in excess
www.bom.gov.au/.../ change/gallery/9.shtml
Major Biomes and Their Vegetation Tundra – no trees, lichens, grasses and shrubs
Taiga (or Boreal Forest) – coniferous evergreens Temperate forests – include evergreens (spruce),
deciduous forests (oaks), mixed forests, and temperate rain forests (sequoias)
Tropical rain forests – greatest amount of diversity in vegetation (vines, orchids, palms)
Grasslands – grasses, prairie clover Deserts – cacti, small bushes
Major Terrestrial Biomes• Geographic distribution of biomes are dependent on temperature,
precipitation, altitude and latitude• Weather patterns dictate the type of plants that will dominate an
ecosystem
faculty.southwest.tn.edu/. ../ES%20%20we16.jpg
570 505 438 408 360 286 245 208 144 66 2 10K Million years before present
Prentice, C.I., Guiot, J., Huntley, B., Jolly D. and Cheddadi, R., 1996, Reconstructing biomes from palaeoecological data: a general method and its application to European pollen data at 0 and 6 ka.
Climate Dynamics 12:185-194.
Global Distribution of Vegetation 18,000 years ago
conifers
tundra
taigagrassland
woodland
desert
Prentice, C.I., Guiot, J., Huntley, B., Jolly D. and Cheddadi, R., 1996, Reconstructing biomes from palaeoecological data: a general method and its application to European pollen data at 0 and 6 ka.
Climate Dynamics 12:185-194.
Global Distribution of Vegetation 6,000 years ago
taigatemperate deciduous
woods & scrub
conifers
grassland desert
tundra
cold deciduous
Prentice, C.I., Guiot, J., Huntley, B., Jolly D. and Cheddadi, R., 1996, Reconstructing biomes from palaeoecological data: a general method and its application to European pollen data at 0 and 6 ka.
Climate Dynamics 12:185-194.
Global Distribution of Vegetation - Present
taigatundra temperate deciduous
grassland
cold deciduous
tropical R.F.
warm mix
18 kya
9 kya
Present
Distribution of spruce and oak forests in Northern Hemisphere since the Last glacial period 18,000 kya
spruce
spruce
spruce
spruce
spruce
ice sheetice
ice
ice
ice
oak
oak
oakoak
• 18,000 years ago Spruce trees and oak trees filled small pockets of habitat – as climates warmed Spruce trees migrated into the Northern Hemispheres and the Oak trees expanded in to Southeastern U.S., Western Europe and Southern Europe
• Shifts in vegetation occur slowly tree species were able to successfully expand into favorable regions
Shifts in Terrestrial Habitat18Kya
9Kya
Present
PRESENT
DAY
BIOMES
tundra
taiga
desert
temp. decd. forest
taiga
desert
desert
trop. rain
forest
grassland
temp rain
forest
scrub forest
Alaska Greenland
Ice landIce land
Siberia
Canada
Location: Regions south of the ice caps of the Arctic and extending across North America, Europe and Siberia (high mountain tops)
Yakutsk
Tundra
N. Europe
Average Temperature: -40°C to 18°C Average Precipitation: 150 to 250 mm of rain per year Type of vegetation: Almost no trees due to short growing season and permafrost; lichens, mosses, grasses, and shrubs
Yakutsk, RussiaLocation:
62.1 N; 129 W
earthobservatory.nasa.gov
Average annual temperatureand precipitation
Temperature: -40°C to 20°C, average summer temperature is 10°C Precipitation:300 to 900 millimeters of rain per year Vegetation: Coniferous-evergreen trees Location: Canada, Europe, Asia, and the United States Other: Coniferous forest regions have cold, long, snowy winters, and warm, humid summers; well-defined seasons, at least four to six frost-free months
Boreal Forest (Taiga)
Canada Europe Asia
S.W. U.S
Beaverlodge, Alberta, Canada
earthobservatory.nasa.gov
Boreal Forest (Taiga)
Average annual temperatureand precipitation
55oN; 119o W
Average Yearly Temperature: Between -30°C to 30°C; hot summers, cold winters; sunlight varies between seasons
Average Yearly Precipitation: 750 to 1,500 mm of rain per year
Vegetation: Deciduous - Broadleaf trees (oaks, maples, beeches), shrubs, perennial herbs, and mosses. Evergreen – (N. America) – Spruce, Hemlock, Pine and Fir treesTemperate Rainforests – (CA, OR, & WA) – made up of Red wood and Sequoias
www.windows.ucar.edu/.../ earth/forest_eco.html
Four types: 1. deciduous forests2. evergreen forests3. mixed deciduous and evergreen4. temperate rain forests
Location: Eastern United States, Canada,Europe, China, and Japan
Temperate Forests
Staunton, Virginia, United States38oN; 79oW
earthobservatory.nasa.gov
Average annual temperature and rainfall
Tropical Forests
General Characteristics:
Average Temperature: 20°C to 25°C, must remain warm and frost-free
Average Precipitation: 2,000 to 10,000 millimeters of rain per year
Average Humidity: Between 77 – 88%
Types of Vegetation: Large trees reaching up to 240 feet, have the most diverse trees than any other biome: vines, orchids, ferns
Tropical rainforests:• Cover less than 6% of Earth’s land surface• Produce more than 40% of Earth’s oxygen• Contain more than half of all the worlds plants and animals • ¼ of all medicines come from rainforest plants• Scientists believe more than 1400 tropical plants
thought to be potential cures to cancer
3 major geographical areas:
1. America: Amazon river basin2. Africa: Zaire basin, small area of W. Africa, Eastern portion of Madagascar3. Asia: West coast of India, Assam, S.E. Asia, New Guinea and Queensland,
Australia
Tropical Rainforest
Amazon river basin Zaire
Madagascar
India S.E. Asia
Queensland
New Guinea
"Rainforests", http://passporttoknowledge.com/rainforest/GEOsystem/Maps/se_asia.html, (3/18/02)
Campa Pita, Belize 15 N latitude
earthobservatory.nasa.gov
Tropical Forest
Average annual temperature and precipitation
Southeast Asia Tropical Rainforest
Monsoons role SE Asia has a tropical wet climate which is influenced by ocean wind
systems originating in the Indian Ocean and China Sea 2 monsoon seasons:
Northeast monsoons (Oct. – Feb) – bring heavy rains to Eastern side of the islands
Southwest monsoons (April – Aug) – more powerful of the two seasons – brings heavy rainfall to the western side of the islands – Eastern side of islands dry – but windy (due to rain shadow)
Change in monsoon cycle bring heavy consequences Ex. 1992 – 1993 – logging degraded primary foresting making it vulnerable
to fires. A drought brought on by El Nino created devastating fires destroying 27,000 km2 of acreage.
In 1998 the same type of thing happened again when El Nino created a weak monsoon season – destroying many plant and animal species.
Location: The prairies of the Great Plains of North America, the pampas of South America, the veldt of South Africa, the steppes of Central Eurasia, and surrounding the deserts in Australia
Temperature: Dependent on latitude, yearly range can be between -20°C to 30°C
Precipitation: About 500 to 900 mm of rain per year
Vegetation: Grasses (prairie clover, salvia, oats, wheat, barley, coneflowers) Other: Found on every continent except Antarctica
Grasslands
Ingeniera White, Argentina40oS; 6oW
earthobservatory.nasa.gov
Average annual temperature and rainfall
Location: Found north and south of theEquator
Temperature: Average of 38°C (day),average of -3.9°C (night)
Precipitation: About 250 mm of rain per yr
Vegetation: Cacti, small bushes, shortgrasses
Other: Perennials survive for several years bybecoming dormant and flourishing whenwater is available. Annuals are referred toas ephemerals because some can completean entire life cycle in weeks.
Deserts
El-Oasr el-Akhdar, Egypt
26oS; 30oE
earthobservatory.nasa.gov
Average yearly temperature and rainfall
So … what are the predictions?????
Present day
Predicted Distribution
forest
forest
grassland
grassland
arid
woodland
shrub land
shrub land woodlandgrasslandgrassland
Climate change p. 104
Arid deserts in Southwestern U.S. will shrink as precipitation increases
Savanna/shrub/woodland systems will replace grasslands in the Great Plains
Eastern U.S. – forests will expand northerly – weather conditions will become more severe
Southeastern U.S. – increasing droughts will bring more fires – triggering a rapid change from broadleaf forests to Savannas
Predicted Change in BiomesLoss of existing habitat that could occur under doubling of CO2 concentration. Shades of red indicate percentage of vegetation models that predicted a change in biome type.
Distribution of Sugar Maple in Eastern North America will change due to an increase in temperature and a decrease in moisture shifting further north east.
present range
Prediction based on Prediction based on increased increased temperature temperature and decrease
precipitation
present range
Predictions of Sugar Maple in Eastern North America
overlap
predicted new growth
predicted new growth
overlap
Wet western slope will shrink and be replaced by pine and oak
Eastern slope will become drier and shift to Juniper and Sagebrush
More Predictions Western Hemlock and Douglas fir found on Western slope Douglas Fir found in
wet coastal mountains of CA and OR will shrink in low lands and be replaced by Western pine species which are more drought tolerant.
Overall Western U.S. climate is predicted to shift to favor more drought tolerant species of pine
Frequency of forest fires will increase, reducing total American boreal forest area.
Shifts in Terrestrial Habitat
• It is predicted that at the end of this century there will be large scale shifts in the global distribution of vegetation in response to anthropogenic climate change.
• With man doubling the amount of carbon dioxide entering into the atmosphere the climate is changing more rapidly then plant migration can keep up.
Potential distribution of the major world biomes under current climate conditions
Projected distribution of the major world biomes by simulating the effects of 2xCO2-equivalent concentrations www.usgcrp.gov/usgcrp/ seminars/960610SM.html
Boreal and Alpine Vegetation
• Research indicates the greatest amount of change will occur at the higher latitudes
• Northern Canada and Alaska are already experiencing rapid warming and reduction of ice cover
• Vegetation existing in these areas will be replaced with temperate forest species
• Tundra, Taiga and Temperate forests will migrate pole ward
• Some plants will face extinction because habitat will become too small (ex. Mountain tops of European Alps)
Predicted changes in Siberian vegetation in response to doubling of CO2
Climate change
Grasslands and Shrub Lands
Grassland will change to deserts or shrub lands Exposing greater amounts of soil Increasing soil temperature – poor nitrogen content – poor plant
growth Barren soil exposed to winds and transported into atmosphere as
dust and trapping IR – leading to more warming
Models of: Climate change Plant growth Soil – water
Predict shifts in distribution of major North American prairie grasses over a 40 year period
Impacts on Lebanon?
recent studies found that the Arab region experienced an uneven increase in surface air temperature ranging from 0.2 to 2.0ºC that occurred from 1970 to 2004
Impact high…
climate change impact 35
Semi-arid and arid regions are highly vulnerable to climate change
If temperature gets higher If precipitation gets lower pressure on natural and physical systems
would be intensified
The Arab region will…
climate change impact 36
Face an increase of 2 to 5.5 C in surface temperature by 2100
Face a decrease in precipitation from 0 to 20%
shorter winters dryer and hotter summers higher rate of heat waves higher level of weather variability more frequent occurrence of extreme
weather events
Impact on freshwater sources
37 climate change impact
Status of freshwater here
climate change impact 38
Reminder: most of the Arab countries are located in arid and semi-arid regions; low and limited water resources + high evaporation
Total water resources = total renewable ground water + internal surface water resources + external surface water resources
First order impacts…
climate change impact 39
Mediterranean hydrological systems Wetter winters Dryer and hotter summers Increase in evaporation from water bodies… Increase Evapotranspiration from crops
Egypt Increase the potential irrigation demand by 6 to
16% by 2100
Drought
40 climate change impact
Drought frequency
climate change impact 41
Increased during the last 20 to 40 years in Morocco, Tunisia, Algeria and Syria Of the 22 drought years in the 20th century, 10
occurred in the last 20 years, and three were successive (1999, 2000, 2001) in Morocco
Recent droughts in Jordan and Syria worst ever recorded
Varying conditions of water shortage in Lebanon in the last 10 years
BUT NOT JUST DROUGHTS
42 climate change impact
Dubbed the 'Manhatten of the desert', Shibam's 2,000-year-old mud-brick buildings are in danger of collapsing after recent floods
Yemen: recent floods (October 2008)
43 climate change impact
Observed Changes in Physical and Ecological Systems (from IPCC 2001)
hydrology / sea ice animals plants study covers study based onglaciers large area remote sensing
04/19/23 44
Those at Risk Northern countries (Russia, Sweden, Finland) ½ of
existing terrestrial habitats at risk
In Mexico, it’s predicted that 2.4% of species will lose 90% of their range and threatened with extinction by the year 2055
Population at greatest risk are the rare and isolated species with fragmented habitats or those surrounded by water, agriculture or human development
Polar bears facing extinction by prolonged ice melts in feeding areas along with decline in seal population
www.sciencedaily.com/.../ 09/050918132252.htm
35% of worlds existing terrestrial habitat predicted to be altered
Studies found that deforestation in different areas of the globe affects rainfall patterns over a considerable region
Deforestation in the Amazon region of South America (Amazonian) influences rainfall from Mexico to Texas and in the Gulf of Mexico
Deforesting lands in Central Africa affects precipitation in the upper and lower U.S. Midwest
Key Conclusions from IPCC
Recent Regional Climate Changes, particularly Temperature Increases, have Already Affected Many Physical and Biological
Systems (high confidence, or >67% sure)
Biotic change: 44 regional studies, 400 plants and animals, 20 to 50 years
Physical change: 16 regional studies, 100 processes, 20-150 yrs
non-polar glacier retreat
reduction in Arctic sea ice extent and thickness in summer
earlier plant flowering and longer growing season in Europe
poleward and upward (elevation) migration of plants, insects and animals
earlier bird arrival and egg laying
increased incidence of coral bleaching
increased economic losses due to extreme weather events
04/19/23 47
Phenology Phenology: the study of a plant or animal’s
progression through its life cycle in relation to the seasons
Another main indicator of climatic fingerprint In Britain, for example, flowering and leafing occur
6 to 8 days earlier for every degree C rise in temperature
04/19/23 48
Phenological Changes Life-cycles of plants and animals have been
affected by global change Temperatures affecting plants growing season,
flowering time and timing of pollination by insects have all been altered
Studies already showing Mediterranean deciduous plants now leaf 16 days earlier
and fall 13 days later than 50 years ago Plants in temperate zones flowering time occurring earlier
in the season Growing season increased in Eurasia 18 days and 12 days
in N. America over past two decades
Phenological Changes
Penuelas J and Filella I 2001. Response to a warming world. Science 294: 793 – 795
Important to know the particular species’ requirements Migratory black-tailed godwit
Shore bird Winters between Britain and Iberia Breeding in summer in Iceland Breeding pairs – high partner fidelity Male and females winter in different locations – but arrive in
Iceland typically within 3 days of each other ?: how this degree of synchrony is maintained when the
environmental conditions at the different sexes’ wintering sites are dissimilar?
Pied flycatcher Migration is timed to availability of food for its nestlings However – in parts of the Netherlands the caterpillars is now at its
food peak early in the season. There – the flycatcher population is in decline
Will it be able to adapt in time?
04/19/23 51
Biological communities and species shift
04/19/23 52
Some species do not migrate – but will shift their geographical position or range in response to CC
Climate is but one factor of many that determine a species’ spatial distribution – species rarely move uniformly with each other in response to climate change
Plus Different species migrate at different rates Thus: takes time for ecological communities to stabilize after a period of CC Species at the leading edge of shifts/migrations tend to migrate faster than
those already established Changes are asymmetrical: species invading faster from lower elevations or
latitudes than resident species receding upslope or poleward Result: increase in species richness of communities at leading edge of migration Transitory biodiversity Plus: many of today’s systems are either managed or bound by land managed by
humans == effective barrier to species migration Problem: old ecological communities disrupted + impeding species migration halted
Arctic lakes
04/19/23 53
1997 - 2004: decline of 1170 large lakes (> 40 ha); 11%
Total regional lake surface area decreased by 6% (93 000 ha); 125 lakes vanished;
Northerly lakes increasing in size – by 12% (13 3000 ha) Increased precipitation in the north Southerly declines in lake area have outpaced
northerly gains in lakes The more southerly permafrost soils no longer
permanently frozen allow lakes to rain
Mountain snow and ice
04/19/23 54
Note: mountain snowpacks affect quantity and timing of water in streams supplying ecosystems in surrounding lowlands
Nearly all mountains of sufficient height on Earth have snow caps Those will be reduced in volume – especially at lower latitudes
Smaller mountain snow caps may be seasonally thicker due to extra precipitation
Already happening – at lower and mid latitudes (China, N.A. and Europe)
Plus: snow-cap melt run off will shift away from summer and fall when biological (and human) demand for water is greatest compared to winter and early spring Annual cycle of water supply for many terrestrial and human systems will
see reduced temporal buffering 1/6th of the human population relies on glaciers and seasonal snowpacks
for water supply Over 50% of river flow dominated by snow melt in: all of Canada, NW
states of US, all of Scandinavia (exc Denmark) Balkan Europe, Russia, NE China, much of Chile, SW Argentina and S of New Zealand
Water and ice
04/19/23 55
In terms of human # - most critical region: China and parts of India
Supports 2 billion people Largest volume of ice outside of polar and
peri-polar regions Nearly 70% of the Ganges’ summer flow and
50-60% of other of the regions’ major rivers: melt water
Tops of mountains…
04/19/23 56
Global warming thermally determined zonation on mountains changes and rises Cannot migrate above mountain summits
Alpine biome is 3% of the vegetated terrestrial surface – and shrinking Ural Mountains
Temperatures risen by more than 4 C in 20th century
Tree lines have risen between 20 and 80 m upslope
Reducing regional alpine lines by 10 – 20%
Mountain pygmy possum (S-E Australia) Habitat favored by skiers Under serious threat
Highland forests of Monteverde, Costa Rica
04/19/23 57
20 species of 50 anurans (frogs and toads) in a 30 km2 study area went extinct – including endemic golden toad (1987) Population crashes all associated with
decline in dry-season mist frequency – due raising of cloud-bank base (presumed)
Changes behavior of animals Harlequin frogs gathered near
waterfalls increased change of attack by parasitic flies increased mortality
‘A message from the frogs’ – Blaustein and Dobston
(Nature 2006)
04/19/23 58
The harlequin frogs of tropical America are at the sharp end of climate change. About two-thirds of their species have died out, and altered patterns of infection because of changes in temperature seem to be the cause.
Climate change has already altered transmission of a pathogen that affects amphibians – leading to widespread populations and extinctions
67 % of the 110 species of harlequin frogs endemic to the region have died in past 20 years
78-83% of extinctions occurred in unusually warm years in the tropics
Shifting temperatures are the ultimate trigger for the expansion of a pathogenic fungus
‘A message from the frogs’ – Blaustein and Dobston
(Nature 2006)
04/19/23 59
“The powerful synergy between pathogen transmission and climate change should give us cause for concern about human health in a warmer world.”
Climate Change and Human Health
Climate change should be billed as a 'health' not 'environmental' disaster
The researchers from George Mason University's Center for Climate Change Communication (4C), whose study was recently published in the BMC public health journal, said the health impacts of climate change had been 'dramatically under-represented' in discussions by scientists, policy-makers and NGOs who instead focused on 'geographically remote' impacts like melting ice caps in the Arctic.
60
Epidemiological Framework
61
Climate change and health: pathway from driving forces, through exposures to potential health impact.
Source: Climate Change and Human Health – Risks and Reponses. Summary (WHO, 2003)
Driving forces
Population dynamics
Unsustainable economic
development
Natural causes
Adaptive capacity
Mitigative capacity
Mitigation measures
Greenhouse gases (GHG)
emissions
CLIMATE CHANGE
Microbial contamination
pathways
Transmission dynamics
Agro-ecosystems, hydrology
Socioeconomics, demographics
Regional weather changes
Heatwaves
Extreme weather
Temperature
Precipitation
Health effects
Temperature-related illness and death
Extreme weather-related health effects
Air pollution-related health effects
Water and food-borne diseases
Vector-borne and rodent-borne diseases
Effects of food and water shortages
Mental, nutritional, infectious and other
health effects
Modulating influences
Health-specific adaptation measures
Research needs
Evaluation of adaptation
Climate Change and Human Health Pathways
POOR RAINS
Inadequate in volume and distribution
Poor Harvest
People Underfed
(Malnutrition)
Poor grass
Less meat, less milk Overgrazing where grass is good
Animals underfed
Over-grazing, trees cut down
for fuel
Grass /vegetation cover lostAnimal deathPoverty
LAND DEGRADATION
64
Model projections
Projected impacts of heat waves Average summer mortality rates attributed to
hot weather episodes Changes with doubling or tripling of carbon
dioxide -> projections of mortality can double or triple
in next several decades
65
What have we seen?Recent Heat Waves
Location Year Approx. No. Deaths Western Europe 2006 3,392* Europe 2003 72,000# India 1998 2,541^ USA 1995 670 USA 1993 200 USA 1966 500 Aust [Melbourne] 1959 145^ -------------------------------------------------------------------------------------------------------------------------------------------------------------------- • * Netherlands 1,000; Belgium 940.• # Italy 20,089; France 19,490; Spain 15,090; Germany 9,355.• ^ Estimation. Total probably higher.
India: June 2003T: 122 degrees F >
1400 deathsJuly FloodsJapanese B encephalitis
Summer 2003 heat wave
France, Germany, Italy, Spain, & Portugal Up to 72,000 deaths
Temperature was 10 degrees C (18 degrees F) above 30 year average
67
European Heatwave 2003
Hotter? Expect more extreme weather events But not all extreme
weather events are attributable to CC Need to know: what is expected with natural variability
assuming no carbon dioxide forcing and with climate forcing from additional anthropogenic greenhouse gases
UK HadCM3 model: an exceptionally warm summer up to 2020 will become a normal summer by the 2040s in Europe … they projected an increase 100-fold over the next four decades
04/19/23 69
So…Effects of Climate Change DIRECT: Thermal stresses: extremes
of hot or cold Respiratory consequences:
changes in patterns of exposure to spores, moulds, etc.
Direct effects: loss of life or health due to: storms, floods,
drought
Air pollution and climate change
71
Emerging infectious diseases
30 diseases new to medicine since 1976 New diseases… Old diseases…
As climate changes Change the range at which they occur Extremes affect vector populations
72
Infectious Diseases
Increased mean, minimum temps along with wetter winters affects the range, proliferation and behavior of vector organisms
Developed world populations generally have more resources to face such problems
Malaria currently affects 350 million people annually, 2 million deaths
Potential for transmission of malaria from 45% - 60% of world’s population
74
75
76
77
78
Biologic response to changes in climate
Global warming and wider fluctuation in weather help to spread diseases
Temperatures – affect growth, development and survival of microbes and the vectors
Weather affects the timing and intensity of disease outbreaks (McMichael et al, 2003)
Biologic response to changes in climate: Infectious diseases Warmer environment and mosquitoes
Boost rate of reproduction Increase the number of blood meal Prolongs their breeding season Shorten the maturation period of microbes they carry Warmer winters – tick-borne lyme disease spreading northward
in Sweden, US and Canada (Epstein, 2005) Heavy downpours
Drive rodents from burrows: risk of zoonotic diseases Create mosquito breeding sites Faster fungal growth in houses Flush pathogens and chemicals into waterways
Milwaukee’s cryptosporidiosis outbreak in 1993 Katrina’s flood: water-borne pathogens and toxins spread.
Extreme weather events and disease clusters Extremes!
High correlation between droughts & floods and rodent-borne and mosquito-borne diseases
Sequence of extremes Example: Hurricane Mitch (Honduras)
6 feet of rain in 3 days
81
Precipitation extremes
Past century average annual precipitation: 7%
Heavy rain events (> 2 inches/day): 14% Very heavy rain events (> 4 inches/day): 20% Western drought + Devastating rains
82
83
Diseases Carried By Mosquitoes
West Nile Malaria
Dengue Fever Yellow Fever
West Nile (1937: Uganda. Now:
Spreading across Canada)
Wet spring. Dry, hot summerClimate change will
influence spread of WNVAnd occurrences of other
Vector diseases
Four main types of transmission cycle for infectious diseases
HUMANS
HUMANS
ANIMALS
ANIMALS
HUMANS
HUMANS
HUMANS
VECTOR/VEHICLE VECTOR/VEHICLE
ANIMALS
ANIMALS
HUMANS
VECTOR/VEHICLE VECTOR/VEHICLE
Anthroponoses
Direct transmission Indirect transmission
Zoonoses
Source: Climate Change and Human Health – Risks and Reponses. Summary (WHO, 2003)
Does climate change have a measurable impact on health?Climate sensitivity: 5% increase in diarrhoeal disease for each 1o C temperature increase (developing countries only)Change in relative risk: Projected temperature changes relative to 1961-1990, overlaid on
population distribution map to give per capita increase in diarrhoea risk.Disease burden attributable to climate change: Relative risk under each scenario/time point multiplied by WHO
estimates of current and future 'baseline' diarrhoea burden in each region. Estimated 2.4% of diarrhoea (47,000 deaths) attributable to CC in 2000,
and approximately 5% ( 60,000 deaths) in 2020. (World Health Report 2002)
88
Primary economic,
technologicalsocial, cultural
drivers
Environmentalchange
e.g., + UVrad thermal stress
Health impact
Health impact
Health impact
Ecosystemchange
+mosquitoes+/- food
Social, politicalEconomicrelations
T, soils
Jobs,povertyconsumption
Socio-economicLevel of risk
Livelihoodpopulation
An EcoHealth View
Climate change willImpact on all these
Relationships!!
INDIRECT: Effects of Climate ChangeMANY UNCERTAINTIES Alterations in range and activity of vector-borne
pathogens e.g., malaria, West Nile virus, dengue Possibility of new infectious disease agents Changes in person-person infections including food-
borne and water-borne Nutritional and health consequences of local and
regional changes in agricultural production Consequences of sea level rise
Loss of home, employment, population displacement
Human impacts of other forms of overload Human environments and livelihoods deteriorate
Social destabilization and conflict will escalate Some of the world’s poorest populations becoming
more “demographically entrapped” McMichael, 1997 limited data
Land exceeds carrying capacity starvation, disease, fratricide
Rwanda prototype 1980s
Vector-borne diseases
Climate change, by altering local weather patterns and by disturbing life-supporting natural systems has significant implications for human health
Models suggest that higher temperatures will enhance the geographic range and transmission rates of vector-borne diseases
Children will be disproportionately affected, as they are more prone to infection and death from parasites.
92
Food security and malnutrition
Many of Africa’s poor are very highly dependent on climate-related factors for their livelihoods.
Weather disruptions exacerbated by climate change negatively impact Africa’s economic growth and food security, and thus aggravate malnutrition
Undernourishment is a well-studied cause of stunted physical and intellectual development and increased disease susceptibility in children.
93
Food Production
In some countries affects nutritional status, child growth, health
Depletion of ocean resources unless offset by advances in aquaculture jeopardize health in developing/poor countries
Sea-level rise
Displacement of coastal population Predicted rise of 0.5 m would immediately
inundate 10% of land in Bangladesh Alters sewage and waste disposal Viability of coral reefs and wetlands Again affects range of disease vectors
Land degradation
Absolute numbers of malnourished persons increasing
Many world’s fisheries overexploited World loss of biodiversity
We have occupied, damaged or eliminated natural habitats of many species
Fastest loss of species ever; we may cause 1/3 of all species alive in last century to be gone before end of this century
Land degradation
Agricultural productivity: to maintain food production have to resort to maintaining vigor and resilience by diversity of species to be source of genetic additives
A high number of medicinal drugs come from naturals; can’t be replicated in labs Science continues to test many new drugs from nature
each year
Climate Change and Environmental Justice Oil-related health consequences
Extraction: Nigeria, Ecuador, Mexico Refining and Benzene Utility plants and mercury Air pollution and inner city truck routes Economic inequities
Vulnerabilities – coping, adaptation Restoration, prevention Public health infrastructure
Still: No nation is immune
98
And the future?
04/19/23 99
Further change is anticipated with further warming
IPCC scientific consensus Warming will continue through the rest of the this
century and beyond Questions: how much warming and at what rate Depends on future emissions of GHG
So what can be done?