Synthesis Report approved in Valencia Nov 2007

1. Climate Change, an un-precedented challenge to society(based on IPCC 4th Assessment Report)IX Bled Forum on Europe7-8th March 2008Gilles Sommeria IPCC Secretariat

2. Synthesis Report approved in Valencia Nov 2007 • WG1 ► The physical science basis of climate system and change, attribution of CC, observation of CC parameters etc • WG2 ►sc-tech, env socio-ec aspects of vulnerability of ecological and socio-ec systems; observed and projected impacts and human responses (adaptation)to actual and expected CC • WG3 ► sc-tech, env, socio- ec aspects of mitigation options, human responses to reduce sources or enhance sinks of GHGs

3. Observed Climate Change 100-yr warming trend (1906-2005) of 0.74oC. Increased since TAR. Warming of the climate system is unequivocal Sea level rise:1960 – 2003: 1.8 mm per yr1993 – 2003: 3.1 mm per yr Decreasing: snow and ice extent Arctic sea ice extent Mountain glaciers IPCC

4. Natural forcings would have led to cooling Decadal averages of observed and simulated global average surface temperature IPCC

5. Observed warming simulated only by models that include anthropogenic forcings Decadal averages of observed and simulated global average surface temperature. IPCC

6. Global and Continental Warming Most of the observed increase in temperature since the mid-20th century is very likely due to the increase in anthropogenic GHG concentrations IPCC

7. CO2 CH4 The atmospheric concentration of CO2 and CH4 in 2005 exceeds by far the natural range of the last 650,000 years

8. Human contribution to climate change Changes in CO2 from ice core and modern data -2 Radiative Forcing (Wm ) Carbon Dioxide (ppm) Global atmospheric concentrations of greenhouse gases increased markedly as result of human activities In 2005 concentration of CO2exceeded by far the natural range over the last 650,000 years 10000 5000 0 Time (before 2005)

9. Global Temperature

10. The heating is not uniform geographically Average T for 2001-2005 compared to 1951-80, degrees C J. Hansen et al., PNAS 103: 14288-293 ( 2006)

11. Sea ice is receding Extent of Arctic summer ice in 1979 (top satellite image) and in 2003 (lower satellite image). North Polar ice cap is sea ice -- it’s floating and so does not change sea level when it melts. But the reduced reflectivity when the ice is replaced by water amplifies the warming effect of greenhouse gases. NASA NASA photograph

12. Mountain glaciers are shrinking Qori Kalis Glacier, Peru 1978 2002

13. Surface melting on Greenland is expanding 1992 2002 2005 In 1992 scientists measured this amount of melting in Greenland as indicated by red areas on the map Ten years later, in 2002, the melting was much worse And in 2005, it accelerated dramatically yet again Source: ACIA, 2004 and CIRES, 2005

14. Heavier precipitation,more intense and longer droughts….

15. … Resulting in Further Warming For next 2 decades a warming of 0,2oC per decade is projected Further warming depends increasingly on scenario Best estimates of temperature increase in 2100 range from 1,8 – 4oC Likely range 1,1-6,4oC Scenario IPCC

16. There is now higher confidence in projected patterns of warming and other regional-scale features. "low" (IPCC, 2007, Fig. SPM-6, adapted) Emissions of Greenhouse Gases "medium" "high" Projected warming in the 21st century shows scenario-independent patterns... Warming is expected to be greatest over land and at most high northern latitudes, and least over the Southern Ocean and parts of the North Atlantic Ocean.

17. 21st Century Water Availability (Runoff) Changes (A1B; Annually averaged) Drier Wetter IPCC

18. Key vulnerabilities to climate change • Some ecosystemsare highly vulnerable: • Coral reefs, marine shell organisms • Tundra, boreal forests, mountain and Mediterranean regions • 20-30% of plant and animal species at risk of extinction • Some regionswill be more affected than others: • The Arctic (ice sheet loss, ecosystem changes) • Sub-Saharan Africa (water stress, reduced crops) • Small islands (coastal erosion, inundation) • Asian mega-deltas (flooding from sea and rivers)

19. Projected impacts of climate change Global temperature change (relative to pre-industrial) 0°C 1°C 2°C 3°C 4°C 5°C Food Falling crop yields in many areas, particularly developing regions Falling yields in many developed regions Possible rising yields in some high latitude regions Water Significant decreases in water availability in many areas, including Mediterranea and Africa Small mountain glaciers disappear – water supplies threatened in several areas Sea level rise threatens major cities Ecosystems Extensive Damage to Coral Reefs Rising number of species face extinction Extreme Weather Events Rising intensity of storms, forest fires, droughts, flooding and heat waves Risk of Abrupt and Major Irreversible Changes Increasing risk of dangerous feedbacks and abrupt, large-scale shifts in the climate system

20. … from 28,7 to 49 GtCO2-eq Emissions of CO2 grew by about 80% Climate Convention signed in 1992! Between 1970 and 2004 Anthropogenic GHG Emissions Grew by 70% IPCC

21. Mitigation urgently needed Mitigation needs to start in short term, even when benefits may only arise in a few decades • Continued GHG emissions at or above current rate would induce larger climatic changes than those observed in 20th century • Emissions of the greenhouse gases covered by the Kyoto Protocol increased by about 70% from 1970–2004

22. Adaptation versus Mitigation Making development more sustainable can enhance both mitigative and adaptive capacity, and reduce emissions and vulnerability to climate change • Adaptation to climate change is necessary to address impacts resulting from the warming which is already unavoidable due to past emissions • However: • Adaptation alone cannot cope with all the projected impacts • of climate change • The costs of adaptation and impacts will increase as global • temperatures increase

23. Mitigation in the period until 2030 In order to stabilize the concentration of GHGs in the atmosphere, emissions would need to peak and decline thereafter. The lower the stabilization level, the more quickly this peak and decline would need to occur. Mitigation efforts over the next two to three decades will have a large impact on opportunities to achieve lower stabilization levels The range of stabilization levels assessed can be achieved by deployment of a portfolio of technologies that are currently available and those that are expected to be commercialised in coming decades. This assumes that appropriate and effective incentives are in place for development, acquisition, deployment and diffusion of technologies and for addressing related barriers Policies that provide a real or implicit price of carbon could create incentives for producers and consumers to significantly invest in low-GHG products, technologies and processes. Such policies could include economic instruments, government funding and regulation

24. Business as usual (BAU) emissions vs. paths for stabilizing CO2 concentration to limit ∆Taverage BAU ( 6°C+) (~3°C) (~2°C) Path for 50% chance of avoiding ∆Tavg >2°C (gold) is much more demanding than path for 50% chance of avoiding >3°C (green).

25. Economic Mitigation Potential Could Offset Projected Growth in Emissions to 2030 or Reduce Below Current Levels IPCC

26. What does US$ 50/ tCO2eq mean? • Crude oil: ~US$ 25/ barrel • Gasoline: ~12 ct/ litre (50 ct/gallon) • Electricity: • from coal fired plant: ~5 ct/kWh • from gas fired plant: ~1.5 ct/kWh Carbon prices between 20-80 US$/tCO2 by 2030 and 30-155 US$/tCO2 by 2050 are consistent with stabilization at 550 ppm CO2-eq2 by 2100

27. Mitigation costs In 2030 macro-economic costs for multi-gas mitigation, consistent with emissions trajectories towards stabilization between 445 and 710 ppm CO2-eq, are estimated at between a 3% decrease of global GDP and a small increase, compared to the baseline. However, regional costs may differ significantly from global averages.

28. Key technologies to reduce emissions Key mitigation technologies and practices currently commercially available Energy Supply Efficiency; fuel switching; renewable (hydropower, solar, wind, geothermal and bioenergy); combined heat and power; nuclear power; early applications of CO2 capture and storage More fuel efficient vehicles; hybrid vehicles; biofuels; modal shifts from road transport to rail and public transport systems; cycling, walking; land-use planning Transport Efficient lighting; efficient appliances and aircodition; improved insulation ; solar heating and cooling; alternatives for fluorinated gases in insulation and Appliances. About 30% of projected GHG emissions by 2030 can be avoided with net economic benefit. Buildings

29. Key policies to reduce emissions Appropriate incentives for development oftechnologies Effective carbon price signal to create incentives to invest in low-GHG products, technologies and processes Appropriate energy infrastructure investment decisions, which have long term effects on emissions Changes in lifestyle and behavior patterns, especially in building, transport and industrial sectors

30. Issues on the future of IPCC (to be discussed at next Session in Budapest 9-10 April 2008) • Increase policy relevance • Improve focus on sustainable development • Focus on economic aspects of climate change • Promote research on regional aspects of climate change • Next Assessment in 5-6 years? • Possible special reports: renewable energies, extremes, climate change and disasters, climate change and soil quality, cryospheric aspects of climate change …

31. Thanks for your attention!