1. Global Climate Change: Past and Future Le Moyne College Syracuse, New York February 3, 2006 Department of Meteorology and Earth and Environmental Systems Institute (ESSI) Penn State University

2. `The balance of evidence suggests that there is a discernible human influence on global climate ' Intergovernmental Panel on Climate Change (United Nations), Second Assessment Report, 1996

3. `There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activity' Intergovernmental Panel on Climate Change (United Nations), Third Assessment Report, 2001

4. THE DATA

5. Climatic Research Unit (‘CRU’), University of East Anglia Surface Temperature Changes

6. Greenhouse Gases and Warming CO 2 Related?

7. TREE RINGS

8. CORALS

9. ICE CORES

10. VARVED LAKE SEDIMENTS

11. HISTORICAL DOCUMENTS

12. RECONSTRUCTED GLOBAL TEMPERATURE PATTERNS

13. Reconstructed Surface Temperatures Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001

14. Reconstructions of Northern Hemisphere mean temperatures for the last 1000 years and instrumental record (black line) From “Wikipedia”

15. CLIMATE MODELS

16. The climate represents a coupled system consisting of an atmosphere, hydrosphere, biosphere, and cryosphere

17. General Circulation Models take into account the full three- dimensional structure of the atmosphere and ocean

18. This alone doesn’t guarantee that they should do a good job in describing climate change ! GCMs do a fairly good job of describing the seasonal cycle in surface temperature January Temp (observations) January Temp (model)

19. Modeled Internal Natural VariabilityObservations

20. INFLUENCE OF EXTERNAL FACTORS

21. The climate is governed by external factors, including the intensity of solar output and volcanic aerosols and greenhouse gas concentrations

22. Solar Variations

23. The climate is governed by external factors, including the intensity of solar output and volcanic aerosols and greenhouse gas concentrations

24. Volcanoes

25. The climate is governed by external factors, including the intensity of solar output and volcanic aerosols and greenhouse gas concentrations

27. GREENHOUSE EFFECT?

29. ENHANCED GREENHOUSE EFFECT?

30. SIMULATIONS OF CLIMATE CHANGE

31. Simulated Annual Global Mean Surface Temperatures Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001 Forced Model simulations

32. Simulated Annual Global Mean Surface Temperatures Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001 Forced Model simulations

33. Simulated Annual Global Mean Surface Temperatures Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001 Forced Model simulations

34. Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001 Future Surface Temperatures Trends?

35. Possible Impacts: North American Drought

36. 1998 Global Temperature Pattern

37. El Nino and North American Drought

38. El Nino vs. North American Drought over the Past Century Increased Drought La Nina El Nino Less Drought Courtesy of E.Cook

39. Katrina (Aug 28 ’05) Destructive Potential of Atlantic Hurricanes Possible Impacts:

40. Rita (Sep 21 ’05) Destructive Potential of Atlantic Hurricanes Possible Impacts:

41. Wilma (Oct 19 ’05) Destructive Potential of Atlantic Hurricanes Possible Impacts:

42. Hurricane Statistics P. J. Webster, G. J. Holland, J. A. Curry, H.-R. Chang Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment, Science, 309, Issue 5742, 1844-1846, 2005.

43. Climate Model Predictions Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment, P. J. Webster, G. J. Holland, J. A. Curry, H.-R. Chang, Science, Vol 309, Issue 5742, 1844-1846, 16 September 2005.

44. Climatological Surface Temperatures January [source: NOAA Climate Prediction Center]

45. Surface Temperature Pattern January ’06 [source: NOAA Climate Prediction Center]

46. Surface Temperature Anomaly Pattern January ’06 [source: NOAA Climate Prediction Center]

47. Temperature Anomaly Pattern (January ’06) Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001

48. CONCLUSIONS Recent global surface temperatures are unprecedented this century, and likely at least the past millennium It is difficult to explain the recent surface warming in terms of natural climate variability Recent surface warming is largely consistent with simulations of the effects of anthropogenic influence on climate Possible impacts of anthropogenic climate change this century include increased drought conditions in the western U.S. and more destructive Atlantic tropical storms and Hurricanes