1. The Changing Terrestrial Arctic Terry Chapin

2. Polar regions are the cooling system for Planet Earth

3. Mann et al. Chapman and Walsh Global to arctic Polar amplification

4. Polar warming is driven by global processes Is mitigation of impacts the only option? Can SEARCH make the case that –Warming has significant ecological impacts? –Warming is affecting human well-being? Within the Arctic? Beyond the Arctic?

6. Aerial extent of glaciers is decreasing (decreasing albedo) (positive feedback to warming) European arctic Russian arctic Total arctic American arctic Hinzman

7. Spring snowmelt is earlier Decreased albedo Positive feedback to warming

8. Sea ice is less extensive Decreased albedo Positive feedback to warming Together these changes in physical environment contribute to polar amplification of global warming

9. Lloyd and Fastie Forests are expanding

10. Decreased albedo –Less masking of snow –Darker, more complex canopy Positive feedback to warming

11. 1949 Chandler River, 50 miles S. of Umiat: Sturm, Racine and Tape: Fifty Years of Change in Arctic Alaskan Shrub Abundance Shrub density has increased 1949 2000 Sturm

12. Indigenous observations indicate that shrub expansion is widespread

13. --- __ --- __ --- __ --- __ Jia et al. GRL, in press

14. Simulated increase in July temperature due to shrub expansion Chapin, Lynch et al.

15. Hinkel, Brown and Nelson Relationship of air temperature to thaw depth depends on surface properties

16. Permafrost temperatures are warming warmer air altered thermal insulation Osterkamp and Romanovsky

17. Permafrost is thawing in many places, not just southern margins

18. Hinzman Hydrology is changing (confirmed by indigenous observations)

19. Oechel and Vourlitis Tundra is becoming drier (in places)

20. Oechel et al. Carbon sequestration is changing (complexity reflects feedbacks)

21. McGuire

22. CO2 efflux is sensitive to warming Increased sequestration in wet areas Increased carbon loss in dry areas Net effect uncertain –Probably positive feedback to warming

23. Methane efflux is increasing Positive feedback to warming –Sensitive to hydrology Overall trace-gas effect is a positive feedback to warming

24. Area burned in W. North America has doubled in last 20 years Kasischki

25. Fire effects on climate Releases carbon to atmosphere –(positive feedback) Reduces masking of snow –(increased winter albedo, negative feedback) Increases vegetation albedo –(negative summer feedback)

26. Warming effects on human well-being Economic impacts are a mixed bag

27. Warming effects on arctic well-being (cultural effects generally negative)

28. Warming effects on global well-being Economic effects generally negative Magnitude still uncertain

29. (Arctic nations) Global-to-arctic: important, understood Arctic-to-global: poorly understood