Download - Global Climate Change: Past and Future
Global Climate Change: Past and Future
Straub Environmental Lecture Salem, OregonMay 31, 2007
Michael E. MannDepartments of Meteorology and Geosciences and
Earth and Environmental Systems Institute
Director, Earth System Science Center,Penn State University
`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
`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
`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
Reconstructed Surface Temperatures
Climate Change 2001: The Scientific Basis, Houghton, J.T.,
et al. (eds.), Cambridge Univ. Press, Cambridge, 2001
Reconstructions of Northern Hemisphere mean temperatures for the last 1000 years and instrumental record (black line)
From “Wikipedia”
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.
The climate represents a coupled system consisting of an atmosphere, hydrosphere,
biosphere, and cryosphere
General Circulation Models (GCMs) take into account the full three-dimensional
structure of the atmosphere and ocean
Natural
1000 1200 1400 1600 1800 2000
Volcanism
Solar
CLIMATE FORCINGS
Crowley, T.J., Causes of Climate Change Over the Past 1000 Years, Science, 289 270-277, 2000.
CLIMATE FORCINGS
Anthropogenic
Greenhouse Gases
Industrial Aerosols
Climate Change 2001: The Scientific Basis, Houghton, J.T.,
et al. (eds.), Cambridge Univ. Press, Cambridge, 2001
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
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
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
Jones, P.D., Mann, M.E., Climate Over Past Millennia, Reviews of Geophysics, 42, RG2002, doi:10.1029/2003RG000143, 2004.
Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001
Future Surface Temperatures Trends?
Model Predictions
Climate Change 2001: The Scientific Basis, Houghton, J.T., et al. (eds.), Cambridge Univ. Press, Cambridge, 2001