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Insights into Climate Dynamics from Paleoclimate Data

Insights into Climate Dynamics from Paleoclimate Data. Interannual Through Millennial Timescales. Michael E. Mann Department of Environmental Sciences University of Virginia. Richard Foster Flint Symposium Dynamical Paleoclimatology In Honor of the Memory of Barry Saltzman

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Insights into Climate Dynamics from Paleoclimate Data

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  1. Insights into Climate Dynamics from Paleoclimate Data Interannual Through Millennial Timescales Michael E. Mann Department of Environmental Sciences University of Virginia Richard Foster Flint Symposium Dynamical Paleoclimatology In Honor of the Memory of Barry Saltzman Yale University, New Haven, CT November 3, 2001

  2. OVERVIEW • The Instrumental Record • Proxy indicators and paleoclimate reconstructions • Model/Data comparisons • Conclusions

  3. Collaborators • Malcolm Hughes • Phil Jones • David Karoly • Tim Osborn • Jonathan Overpeck • David Rind • Scott Rutherford • Gavin Schmidt • Drew Shindell • Ron Stouffer • Anne Waple • Rob Allan • Ray Bradley • Keith Briffa • Ed Cook • Curt Covey • Tom Crowley • Heidi Cullen • Rosanne D’Arrigo • Tom Delworth • Chris Folland • Malcolm Hughes

  4. The Instrumental Record • Proxy indicators and paleoclimate reconstructions • Model/Data comparisons • Conclusions

  5. Instrumental Surface Temperature Record Grayshaded: 1902-1993 Checkboard: 1854-1993 Climatic Research Unit (‘CRU’), University of East Anglia

  6. Instrumental Surface Temperature Record El Niño “Niño3”

  7. Instrumental Surface Temperature Record Climatic Research Unit (‘CRU’) University of East Anglia

  8. Instrumental Surface Temperature Record Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001

  9. Instrumental Surface Temperature Record Five leading patterns of global temperature variation during the 20th century. Mann, M.E., Bradley, R.S., Hughes, M.K., Global-Scale Temperature Patterns and Climate Forcing Over the Past Six Centuries, Nature, 392, 779-787, 1998.

  10. The Instrumental Record • Proxy indicators and paleoclimate reconstructions • Model/Data comparisons • Conclusions

  11. TREE RINGS

  12. CORALS

  13. ICE CORES

  14. VARVED LAKE SEDIMENTS

  15. HISTORICAL DOCUMENTS

  16. Annual Resolution Proxy Climate Indicators  tree-ring; + PCs of dense tree-ring networks,  ice core C coral  Early instrumental/historical (temperature)  Early instrumental/historical (precipitation)

  17. Annual Resolution Proxy Climate Indicators Mongolia Tree Ring Ice Core Fisher et al (eds. Jones, P. D., Bradley, R. S. & Jouzel, J.) (Springer-Verlag Berlin Heidelberg, Berlin, 1996). D'Arrigo, R. et al, Geophysical Research Letters28, 543-546 (2001). Baffin Island Canada Sediment Core Hughen et al, Holocene 10, 1: 9-19 (2000).

  18. Annual Resolution Proxy Climate Indicators INSTRUMENTAL TEMPERATURE RECORD GLOBAL PROXY CLIMATE RECORDS

  19. Instrumental Surface Temperature Record Five leading patterns of global temperature variation during the 20th century. Mann, M.E., Bradley, R.S., Hughes, M.K., Global-Scale Temperature Patterns and Climate Forcing Over the Past Six Centuries, Nature, 392, 779-787, 1998.

  20. Reconstructed Surface Temperatures

  21. Reconstructed Surface Temperatures Mann, M.E., Bradley, R.S., Hughes, M.K., Global-Scale Temperature Patterns and Climate Forcing Over the Past Six Centuries, Nature, 392, 779-787, 1998.

  22. Reconstructed Surface Temperatures VERIFICATION

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

  24. Instrumental Surface Temperature Record El Niño “Niño3”

  25. Reconstructed Surface Temperatures Cold-season Nino3 index Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001

  26. The Instrumental Record • Proxy indicators and paleoclimate reconstructions • Model/Data comparisons • Conclusions

  27. Observations Modeled Natural Variability

  28. Climate Forcings Anthropogenic Industrial Aerosols Greenhouse Gases

  29. 1000 1200 1400 1600 1800 2000 Climate Forcings Volcanism Solar Natural

  30. Temperature Solar Irradiance Relationship between Northern Hemisphere Temperature and Potential Predictors Greenhouse Gases Volcanism Mann, M.E., Bradley, R.S., Hughes, M.K., Global-Scale Temperature Patterns and Climate Forcing Over the Past Six Centuries, Nature, 392, 779-787, 1998.

  31. Simulated Annual Global Mean Surface Temperatures Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001 HADCM3 Coupled Ocean-Atmosphere Model

  32. Science

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

  34. North Atlantic Oscillation Trend in NAO in past couple decades explains enhanced recent warming in certain regions of Northern Hemisphere

  35. North Atlantic Oscillation “Little Ice Age”

  36. North Atlantic Oscillation Empirical LIA winter cooling in Europe associated with an NAO trend due to solar irradiance changes, interacting w/ stratospheric atmospheric dynamics and chemistry NASA/GISS Model (Shindell et al, in press)

  37. Atlantic Multidecadal Oscillation

  38. Atlantic Multidecadal Oscillation

  39. Atlantic Multidecadal Oscillation

  40. Atlantic Multidecadal Oscillation A clear 50-70 year timescale signal apparently centered in the Atlantic is evident from proxy-reconstructions of SST during the past few centuries

  41. Atlantic Multidecadal Oscillation The GFDL coupled model exhibits a robust 50-70 year timescale signal, which is insensitive to model resolution

  42. Atlantic Multidecadal Oscillation Observations Model

  43. Atlantic Multidecadal Oscillation The signal in the model represents a modulation of the intensity of the North Atlantic THC with oceanic feedbacks Signal is oceanic in origin, but is modified by the atmosphere

  44. CONCLUSIONS • Proxy-based reconstructions of Hemispheric temperature variations over past millennium are consistent with model-based estimates of both forced and internal climate variability • 20th century warming is inconsistent with natural climate variability, but can be explained by anthropogenic influence on climate • Little Ice Age temperature reconstructions consistent with enhancement of NAO-type pattern in response to past solar variations produced in recent model simulation • Internal multidecadal pattern of climate variability consistent with intrinsic model of ocean-atmosphere variability evident in long control simulations of coupled ocean-atmosphere models.

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