1. What we know about global climate change Philip Mote (206) 616-5346 philip@atmos.washington.edu philip@atmos.washington.edu University of Washington

2. What we know (high confidence) Earth’s climate is changing Humans are involved and the pattern is unlike natural changes Global average temperature is likely to increase 1.4-5.8°C this century, most land areas more We know this through peer-reviewed research and assessments

3. Evidence of warming Direct measurements Glaciers receding Ice shelves collapsing Snow declining and streamflow shifting Shifts in ranges and behavior of species

4. Understanding recent climate history Recent trend: +0.5°C (0.9°F) in 30 yrs Human influence emerges

5. Larsen B Ice shelf Antarctica January 31, 2002 MODIS data Courtesy NSIDC

6. February 17

7. February 23

8. March 5

9. Avoiding Dangerous Climate Change : Exeter Feb 2005 Antarctic Peninsula Glacier Acceleration “cork from bottle” analogy Larsen A – x3 increase in flow speed of 2 feed glaciers Larsen B – x2-x6 increase in flow speed of 4 feed glaciers Hektoria glacier lowered by ~40m in 6 mo Glaciers south of collapse region unaffected ~ 0.06mm/y global msl contribution? Work in progress

10. Rapid global sea level rise

11. 11 Local evidence of warming

12. 1928 2000 The South Cascade glacier retreated dramatically in the 20th century Courtesy of the USGS glacier group

13. 3.6°F 2.7°F 1.8°F 0.9°F

14. Puget Sound area

15. Race Rocks lighthouse, Victoria

16. As the West warms, winter flows rise and summer flows drop Figure by Iris Stewart, Scripps Inst. of Oceanog. (UC San Diego)

17. Stewart et al., 2004; Stewart et al., 2005 Spring-pulse dates Centers of Mass By several measures, Western snowfed streamflow has been arriving earlier in the year in recent decades Spring pulse Center time

18. April 1 snowpack: no decline at high elevations

19. ...but large declines at low elevations

20. Green daily flow records dating to <1935

21. Metrics of flow Center date JJAS flow

22. Center date of annual flow As observed elsewhere, mean inflow to Puget Sound is shifting earlier as the snowpack declines

24. Data from Climate Monitoring and Diagnostics Lab., NOAA. Data prior to 1973 from C. Keeling, Scripps Inst. Oceanogr. Changing atmospheric composition: CO 2 Mauna Loa, Hawaii

25. Carbon dioxide: up 32%

28. Natural Climate InfluenceHuman Climate Influence All Climate Influences

30. Climate change commitment: at any point in time, we are committed to additional warming and sea level rise from the radiative forcing already in the system: the brakes work slowly! (Meehl et al., 2005: How much more warming and sea level rise? Science, 307, 1769—1772)

31. Recent findings and events zOcean acidification zIntensity and destructiveness of tropical cyclones may be increasing (controversial) zUnprecedented 2003 European heat wave may have been accentuated by warming

35. Hurricane Catarina - first recorded South Atlantic tropical storm, March 2004

36. Total: 27 (vs 21 in 1933) Total: 13 (vs 12 in 1969)

37. Conclusions zHuman influence on climate has emerged zWarming and its consequences will continue even after greenhouse gas concentrations are stabilized z