Transcript Adaptation & vulnerability

IPCC WG2 Impacts, adaptation & vulnerability
Recent & future impacts of CC and sea-level rise (SLR) (Chap. 1-16)
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on 6 systems/sectors and 8 major regions
Adaptation & vulnerability (Chap. 17-20)
Includes 4 cross-chapter case studies
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E.g. Coral reefs, mega-deltas, role of indigenous knowledge for CCA
I. Observed changes in physical/biological systems
Physical systems (snow, ice, permafrost, hydrology, coastal processes)
Biological systems (terrestrial, marine, freshwater)
II. Impacts by sector - AG, FO, ecosystems, water resources
Variety of ∆trends in weather/climate with impacts on AG and water resources
↑ Frequency warm/hot days/nights
and warm spells/heat waves
 ↑ yields in cold, ↓yields in warm environments,
↑ insect outbreaks, ↑risk of wildfire
snow melt related water resources, ↑water demand
↑Area affected by drought
 ↓ yields/crop damage; ↑ livestock deaths
↑risk of wildfire
water stress more widespread, land degradation
↑Frequency heavy rainfall events,
intense tropical cyclones
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Sea level rise
 Salinisation of irrigation water and ecosystems,
↓ freshwater availability
Damage to crops, trees, coral reefs
waterlogging of arable land
Soil erosion, ↓water quality
Key impacts – Fresh water resources
Averall net negative impact in all regions, benefits from ↑annual runoff in some
areas (moist tropics, high latitudes) outweighed by shifts in water supply, water
quality and flood risks
Causes: ↑temp & evaporation, SLR, rainfall variability
↑Flood hazard: likely 20% of world population living in river basins affected by 2080s
esp. megadeltas; beyond 2100 SLR up to 6 m possible due to deglaciation of
Greenland and possibly West Antarctic ice sheets
↑Water stress in 62-76% of global land area by 2050s, +0.4-3.4 billion people
exposed
• ↓surface water availability and groundwater recharge in semi-arid low and midlatitudes, # affected people: Asia >Africa >>Latin America
• regionally, large changes in irrigation water demand (likely)
Key impacts – Relative Change in Fresh water availability
Relative change!
∆% in 2081-2100 cp. to 1981-2000
Source: Fig. 5 in TS WG2, based on ensemble mean for SRES A1B from Nohara et al (2006)
Key impacts – Marine & terrestrial ecosystems
Causes: CC associated disturbances (flood, drought, wildfire, insects, ocean
acidification), other global change drivers
Resilience of many ecosystems likely to be exceeded by 2100  threshold
responses, many irreversible (e.g. biodiversity loss, changes in ecosystem
structure), terrestrial biosphere becoming net carbon source (likely)
Key ecosystem properties (e.g. biodiversity) or regulating services (e.g. carbon
sequestration) impaired (very likely)
+1-2°C: negative impacts for some systems (e.g. coral bleaching, endemic plants &
fauna in S-Africa, polar systems)
+2-3°C: major biome changes very likely (e.g. coral mortality, 20-80% loss of
Amazonian rainforest, globally 20-30% species extinction)
> +3°C: widespread, heavy impacts on biomes, globally significant extinctions
Key impacts –Terrestrial ecosystems ∆ 2000-2100
DGVM LPJ + HadCM3
SRES A2
↓ Grass/tree cover
↓ Forest/woodland
DGVM LPJ + ECHAM5
SRES B1
∆Yield
Key impacts – Agriculture, forestry
Maize
Causes: ↑temp & evaporation, rainfall variability, extreme events
Agriculture
• HL:↑yields for ↑temp 1-3°C, ↓yields >3°C
• LL: ↓yields even for ↑temp 1-2°C
• CO2 benefits outweighed by ∆temp, rainfall
• Effects extreme events > ∆mean climate?
• fire risks, pests and diseases
• ↑irrigation water demand +5-20% by 2080s (globally)
• Livestock: diseases (e.g. bluetongue), heat and water stress,
∆forage quality
∆Yield
Forestry
• land-use change/deforestation more important
• ∆production: globally modest↑; short-term ↑production in LL, long
term ↑production in HL
∆Yield
• ↑fuelwood use possible due to ↑energy prices/biofuels
• Interaction between disturbances (storm, insects, droughts, fires)
∆Yield as f(Temp, rainfall, CO2)
With, Without adaptation
Wheat
Rice
∆ Agricultural production in 2050
Key impacts – Fisheries, food security
Fisheries (capture fisheries & aquaculture)
• Causes: ↑temp stress & pH, ↑extreme events & diseases, conflict with coastal defence
• Local extinction of fish species at edges of ranges (e.g., salmon, sturgeon), long-term
impacts of coral reef damages
• ∆primary production & transfer
• Long-term: slowing MOC affects marine ecosystem productivity  ↓planktion biomass
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Lake Tanganyika: ↓fish yields ~-30%
Lower Mekong: ∆food chain due to ↓water quality, ∆vegetation pattern, salt water intrusion
Food security
• ↑global food production for ↑temp < 3°C, beyond ↓production, ↑cereal prices
• Globally, only slight ↑people at risk of hunger due to socio-economic development
• Subsistence sectors threatened (notably Africa, parts of Asia), by 2080 ~75% of people at
risk of hunger from Africa
• ↑food-import dependence of many developing countries
• Complex, local negative impacts on small holders
Key impacts – Coasts & Health
Coastal ecosystems
 all vulnerable, esp. corals, salt marshes and mangroves
 ↑coral bleaching and mortality due to ↑SST +1-3°C in 21st century
 Global loss of ~1/3 of coastal wetlands for 36 cm SLR (2000-80), largest losses:
Atlantic & Gulf of Mexico coasts, Mediterranean, Baltic, small-islands
↑ Coastal flooding in low-lying areas due to SLR & intense storms,2-3x population
currently at risk
Health:
• ↑deaths/diseases from extreme events, ∆ distribution of disease vectors
• slight ↑diarrhoe diseases in low-income regions by 2030
Major issues: Yields & food security
III. Impacts by region - Africa
↓LGP, e.g. on Sahel margin
↑water stress, ↓runoff by 2050
↑rainfall, ↑runoff (floods)
Malaria in higlands of Ethiopia,
Kenia, Rwanda, Burundi (modest
by 2050s, strong for 2080s)
Ecosystem impacts
Fishery in lakes affected
↓crop yield, AG-GDP loss 2-4%
Coastal settlements affected by
SLR and flooding
∆coastal ecosystems affecting
fisheries & tourism
↑water stress, ↓crop yield
S-expansion of Malaria likely
fynbos & Succulent Karoo very vulnerable  major
shifts
↓food security due to CC, HIV/Aids, poor governance
∆AG
∆Ecosystems
∆Water availability
∆Rainfall/storms
Desert dune shifts
SLR/flooding
∆Health
Conflict zones
Key impacts - Small islands in developing countries
Major issues: coastal ecosystems, water availability, infrastructure
Ecosystems
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SLR and ↑water temperature  ↑ beach erosion, degradation of mangroves and
coral reefs  negative impacts on tourism
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Ecosystems on high latitude islands/Mediterranian more affected but less relevant for
food security
Water availability
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↓ freshwater lenses on atolla up to 29% resulting from SLR related land loss
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Without adaptation, agricultural economic costs likely to reach 2-3% and 17-18% of
2002 GDP by 2050 for SRES B2 and A2, respectively
Health issues, infrastructure
Key impacts - Asia
Major issues: Water availability & flooding
Flooding/melting of glaciers
• Coastal areas, esp. megadelta regions in S/E/SE-Asia at greatest risk due to flooding
• Example 1 m SLR Mekong River delta  50% loss of mangrove area, ~100,000 ha of arable
land becoming salt marsh; floods affecting 3.5-5 million people
• Decay of glaciers: e.g. Tibetan Plateau; Himalayan glaciers to 1/5 by 2030s
• Coral reefs: ~30% lost in next 30 years due to multiple stresses
↑Water stress
• 0.12-1.2 billion people affected by 2020s/2050s
• AG irrigation demand +10% in arid/semi-arid E-Asia for ↑temp +1°C
• ↑forest fires in N-Asia
• ↑crop yields up to 20% in E/SE-East Asia, ↓crop yield up to 30% in C/S-Asia by 2050s; due
to rapid population growth risk of hunger remains high in several countries
• Ex: India – ↓freshwater availability by 47% in 2025 due to CC and pop. growth, ↑intense rain
and frequent flash floods during monsoon  more surface runoff, less groundwater recharge
Key impacts - Latin America
Major issues:
↓crop/livestock productivity & biodiversity
SLR, mangroves
↑Extreme events
(e.g. hurricanes)
Savannisation of E-Amazonia,
↓↓loss of tree species
↓water availability,
hydropower
Current & future
biodiversity loss
↓Coffee suitability
Severe land degradation
↑aridity,
water stress,
↓yields
Storm surges, SLR
(Rio de la Plata)
VI. Vulnerability
Def. Vulnerability
Degree to which geophysical/biological/socio-economic systems are susceptible to, and
unable to cope with, adverse impacts of CC
V = Impact + adaptive capacity
= f(magnitude, timing, distribution, reversibility and likelihood of impacts and potential for
adaptation  development pathway, other stresses)
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varies on geographic/sectoral contexts, as well as between communities;
particularly vulnerable are poor people, women, children and elderly
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Sustainable development  ↑response capacity, ↓vulnerability, CC hampers
achievement of MDGs
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↑vulnerability with ↑temp: >+2° ↑key impacts at all scales, >+4° major ↑vulnerability
Most vulnerable systems/regions
The Arctic: heavy impacts on natural systems (tundra, boreal forest, ice biomes)
Africa, especially Sub-Sahara, because of current low adaptive capacity, ↑water stress in dry
tropics affecting agriculture, health issues and impacts on ecosystems
Small islands, due to high exposure of population and infrastructure to SLR and storm surges
Megadeltas, due to large populations & high exposure to SLR, storm surge and floods
Global vulnerability – 2050 (SRES A2)
Current adaptive capacity
Enhanced adaptive capacity
Severe
Moderate
Modest
Little
No data
Mitigation + Current adaptive capacity
Mitigation + Enhanced adaptive capacity
V. Adaptation to climate change
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Adaptation so far limited, but wide range of adaptation options available
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Extension needed, barriers, limits and costs not fully understood
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Autonomous – planned adaptation
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Ex: cereal cropping systems ∆variety/planting time can avoid -10-15% yield (+12°C), >3°C adaptive capacity in low latitudes exceeded
Mitigation & Adaptation
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Mitigation benefits more global, but time lag; Adaptation benefits more
local/regional, but more immediate
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Both needed to minimize impacts and increase adaptive capacity
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synergies, e.g. afforestation, agro-forestry
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trade-offs require more knowledge about costs and benefits
Adaptation options by sector - Examples
Others:
e.g. grain storage, early
warning systems, access to food
markets, crop insurance, disaster
preparedness planning, strengthening
institutions, community empowerment
Knowledge Gaps
Agriculture, forestry, fisheries
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Comprehensive assessment of CC impacts (also short-term) on AG & food security and CCA strategies for
different scenarios/scales for developing countries
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Identification of highly vulnerable micro-environments/households, provide agronomic/economic coping
strategies
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CO2 response of non-cereal crops, incl. root crops/millet relevant for poor
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Crop model intercomparison studies
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CC impacts on non-timber forestry products, inconsistencies between impact and yield forest models
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Combined effects of ↑CO2 and CC on pest, weeds, diseases
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Impact of CC on biofuel crops and on aquatic biota
General
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Impacts under different development pathways
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Assessment of regional scale impacts hampered by resolution of climate models, lack of observation data
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Avoided damages by different level of emission reductions
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Synergies adaptation, mitigation & sustainable development
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Costs