1. Consequences of Global Warming (IPCC SPM-AR4) 1)Reduced uptake of CO2 by land and ocean in warmer climate 2)Rising sea levels (0.3 to 0.6m by 2100)…. at a minimum 3)Ocean pH will decrease by 0.14 to 0.35 (already down 0.1) 4)Snow cover will decrease, permafrost melt, sea ice melt…. albedo 5)Extreme events (temperature and precipitation) will become more frequent 6)Tropical cyclones will become more intense (Dr. Curry) 7)Storm tracks will move poleward 8)Rainfall will increase in the high latitudes, decrease in the subtropics 9)Meridional overturning of Atlantic ocean will decrease

3. SRES: Special Report on Emission Scenarios Range of scenarios: B1  CO2 at 600ppm by 2100*385ppm today A1B  850ppm by 2100 A1F1  1550ppm by 2100

4. The uncertain climate future Range of CO2 emissions scenarios: Strict international agreements  CO2 at 600ppm by 2100*390ppm today Mid-ground  850ppm by 2100 280ppm 1800 Business as usual  1550ppm by 2100 Lower limit: 1°C by 2100 Upper limit: 6.5°C by 2100

5. Projected temperature change: global view Take-homes: -poles warm more -land warms more -ocean warming patchy and complex uneven warming will shift rainfall patterns

6. IPCC SPM-AR4

7. Comparison of model & recent data Model: IPCC 2001 Stations: Church and White, 2006 Satellite: Cazenave and Nerem, 2004 (updated)

8. Greenland

9. Stroeve et al, 2008

11. http://nsidc.org/sotc/iceshelves.htmlhttp://nsidc.org/sotc/iceshelves.html Ice Shelves are critical to the stability of the large ice sheets

12. Are the ice sheets melting? mass loss at lower altitudes mass gain at higher altitudes net mass loss observed

14. Red=West Antarctic Ice Sheet Green= East Antarctic Ice Sheet large year-to-year (interannual) variations hard to quantify trend suggestion that West Antarctic Ice Sheet is melting faster -supported by recent article by NASA scientists (Rignot et al, 2008)

15. Steig et al, Nature 2009 trends for 1979-2003 trends for 1951-1981 New evidence that Antarctica is warming nearly everywhere, at least for the last several decades

16. IPCC SPM-AR4 HOWEVER…. “Business as usual” strict international agreements on CO 2

17. Cuffey et al., 2000 During the last interglacial, temperatures were warmer than pre-industrial (by 5ºC), and sea level was higher by 5-6m Greenland + West Antarctic = 14m

18. Sea level rise: IPCC says 7” to 23” by 2100, much more if rapid ice sheet collapse occurs My vote is for a 1m rise (30 inches)

19. The climate system is not in equilibrium yet, still will warm for centuries to come….