IPCC WG2 Impacts, adaptation & vulnerability

1. IPCC WG2 Impacts, adaptation & vulnerability Recent & future impacts of CC and sea-level rise (SLR)(Chap. 1-16) • on 6 systems/sectors and 8 major regions Adaptation & vulnerability(Chap. 17-20) Includes 4 cross-chapter case studies • E.g. Coral reefs, mega-deltas, role of indigenous knowledge for CCA

2. I. Observed changes in physical/biological systems Physical systems (snow, ice, permafrost, hydrology, coastal processes) Biological systems (terrestrial, marine, freshwater)

3. 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  andwarm spells/heat waves ↑Area affected by drought  ↑Frequency heavy rainfall events,  intense tropical cyclones Sea level rise  ↑ yields in cold, ↓yields in warm environments, ↑ insect outbreaks, ↑risk of wildfire snow melt related water resources, ↑water demand ↓ yields/crop damage; ↑ livestock deaths ↑risk of wildfire water stress more widespread, land degradation Damage to crops, trees, coral reefs waterlogging of arable land Soil erosion, ↓water quality Salinisation of irrigation water and ecosystems, ↓ freshwater availability

4. 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 mid-latitudes, # affected people: Asia >Africa >>Latin America • regionally, large changes in irrigation water demand (likely)

5. Key impacts – Relative Change in Fresh water availability ∆% in 2081-2100 cp. to 1981-2000 Relative change! Source: Fig. 5 in TS WG2, based on ensemble mean for SRES A1B from Nohara et al (2006)

6. 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

7. Key impacts –Terrestrial ecosystems ∆ 2000-2100 ↓ Grass/tree cover ↓ Forest/woodland DGVM LPJ + HadCM3 SRES A2 DGVM LPJ + ECHAM5 SRES B1

8. Key impacts – Agriculture, forestry ∆Yield Maize Wheat Rice 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 Forestry • land-use change/deforestation more important • ∆production: globally modest↑; short-term ↑production in LL, long term ↑production in HL • ↑fuelwood use possible due to ↑energy prices/biofuels • Interaction between disturbances (storm, insects, droughts, fires) ∆Yield ∆Yield ∆Yield as f(Temp, rainfall, CO2) With, Without adaptation

9. ∆ Agricultural production in 2050

10. 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 • 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

11. 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

12. III. Impacts by region - Africa ↓LGP, e.g. on Sahel margin ↑water stress, ↓runoff by 2050 Major issues: Yields & food security ∆AG ∆Ecosystems ∆Water availability ∆Rainfall/storms Desert dune shifts SLR/flooding ∆Health Conflict zones ↑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

13. Key impacts - Small islands in developing countries Major issues: coastal ecosystems, water availability, infrastructure Ecosystems • SLR and ↑water temperature  ↑ beach erosion, degradation of mangroves and coral reefs  negative impacts on tourism • Ecosystems on high latitude islands/Mediterranian more affected but less relevant for food security Water availability • ↓ freshwater lenses on atolla up to 29% resulting from SLR related land loss • 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

14. 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

15. Key impacts - Latin America 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 Storm surges, SLR (Rio de la Plata) ↑aridity, water stress, ↓yields Major issues: ↓crop/livestock productivity & biodiversity

16. 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) • varies on geographic/sectoral contexts, as well as between communities; particularly vulnerable are poor people, women, children and elderly • Sustainable development  ↑response capacity, ↓vulnerability, CC hampers achievement of MDGs • ↑vulnerability with ↑temp: >+2° ↑key impacts at all scales, >+4° major ↑vulnerability

17. 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

18. Global vulnerability – 2050 (SRES A2) Severe Moderate Modest Little No data Current adaptive capacity Enhanced adaptive capacity Mitigation + Current adaptive capacity Mitigation + Enhanced adaptive capacity

19. V. Adaptation to climate change • Adaptation so far limited, but wide range of adaptation options available • Extension needed, barriers, limits and costs not fully understood • Autonomous – planned adaptation • Ex: cereal cropping systems ∆variety/planting time can avoid -10-15% yield (+1-2°C), >3°C adaptive capacity in low latitudes exceeded Mitigation & Adaptation • Mitigation benefits more global, but time lag; Adaptation benefits more local/regional, but more immediate • Both needed to minimize impacts and increase adaptive capacity • synergies, e.g. afforestation, agro-forestry • trade-offs require more knowledge about costs and benefits

20. 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

21. Knowledge Gaps Agriculture, forestry, fisheries • Comprehensive assessment of CC impacts (also short-term) onAG & food security and CCA strategies for different scenarios/scales for developing countries • Identification of highly vulnerable micro-environments/households, provide agronomic/economic coping strategies • CO2 response of non-cereal crops, incl. root crops/millet relevant for poor • Crop model intercomparison studies • CC impacts on non-timber forestry products, inconsistencies between impact and yield forest models • Combined effects of ↑CO2 and CC on pest, weeds, diseases • Impact of CC on biofuel crops andon aquatic biota General • Impacts under different development pathways • Assessment of regional scale impacts hampered by resolution of climate models, lack of observation data • Avoided damages by different level of emission reductions • Synergies adaptation, mitigation & sustainable development • Costs