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Global Climate Change: Past and Future

Global Climate Change: Past and Future. `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.

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Global Climate Change: Past and Future

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  1. Global Climate Change: Past and Future

  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 overthe last 50 years is attributable to human activity' Intergovernmental Panel on Climate Change (United Nations), Third Assessment Report, 2001

  4. `Most of the observed increase in globally averaged temperatures since the mid-20th century is verylikely due to the observed increase in anthropogenic greenhouse gas concentrations’ Intergovernmental Panel on Climate Change (United Nations), Fourth Assessment Report, 2007

  5. OBSERVATIONS

  6. Surface Temperature Changes Gray: back to beginning of 20th century Boxes: back to mid 19th century

  7. Surface Temperature Changes

  8. Surface Temperature Changes

  9. Internally Consistent Changes in Other Variables

  10. Greenhouse Gases and Warming CO2 Related?

  11. ENHANCED GREENHOUSE EFFECT?

  12. TREE RINGS

  13. CORALS

  14. ICE CORES

  15. VARVED LAKE SEDIMENTS

  16. HISTORICAL DOCUMENTS

  17. RECONSTRUCTED GLOBAL TEMPERATURE PATTERNS

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

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

  20. Mt Kilimanjaro

  21. Mt Kilimanjaro

  22. Thompson, L. G., Mosley-Thompson, E., Davis, M. E., Lin, P. N., Henderson, K., and Mashiotta, T. A., 2003, Tropical glacier and ice core evidence of climate change on annual to millennial time scales, Climatic Change, v. 59, p. 137-155.

  23. MODEL SIMULATIONS

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

  25. General Circulation Models (GCMs) take into account the full three-dimensional structure of the atmosphere and ocean

  26. 1000 1200 1400 1600 1800 2000 CLIMATE FORCINGS Volcanism Solar Natural Crowley, T.J., Causes of Climate Change Over the Past 1000 Years, Science, 289 270-277, 2000.

  27. CLIMATE FORCINGS Anthropogenic Industrial Aerosols Greenhouse Gases Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001

  28. 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

  29. 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

  30. 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

  31. Jones, P.D., Mann, M.E., Climate Over Past Millennia, Reviews of Geophysics, 42, RG2002,doi:10.1029/2003RG000143, 2004.

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

  33. Model Predictions Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001

  34. Model Predictions

  35. Possible Impacts? Warmer summer temperatures +less/no increase in continental precipitation = more frequent summer drought

  36. Greenland Melting… (source: Arctic Impacts of Arctic Warming, Cambridge Press, 2004). Possible Impacts?

  37. Possible Impacts? …Sea Level Rise

  38. Possible Impacts? +10 meters …Sea Level Rise

  39. Possible Impacts? Katrina (Aug ’05) …More Destructive Hurricanes

  40. Possible Impacts? Rita (Sep ’05) …More Destructive Hurricanes

  41. Possible Impacts? Wilma (Oct ’05) …More Destructive Hurricanes

  42. Climate Model Predictions Knutson, T. K., and R. E. Tuleya, 2004: Impact of CO2-induced warming on simulated hurricane intensity and precipitation: Sensitivity to the choice of climate model and convective parameterization. Journal of Climate, 17(18), 3477-3495.

  43. Hurricane Statistics Emanuel, K. (2005), Increasing destructiveness of tropical cyclones over the past 30 years, Nature, online publication; published online 31 July 2005 | doi: 10.1038/nature03906

  44. CONCLUSIONS • Recent global surface temperatures are unprecedented in a long-term context • 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, coastal flooding, and more destructive Atlantic Hurricanes

  45. ``RealClimate is a commentary site on climate science by working climate scientists for the interested public and journalists. We aim to provide a quick response to developing stories and provide the context sometimes missing in mainstream commentary.’’ Gavin Schmidt, Michael Mann Eric Steig, William Connolley, Ray Bradley, Stefan Rahmstorf, Rasmus Benestad, Caspar Ammann, Thibault de Garidel, David Archer, Ray Pierrehumbert

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