Rapid Climate Change Lauren Elmegreen ESP Seminar April 28, 2006 Lauren Elmegreen ESP Seminar April 28, 2006

Past Climate: Lake Agassiz Teller, JT and DW Leverington, 2004

Sea Ice and Abrupt Climate Change Denton GH et al, 2005

Possible scenario in current conditions…

Schmittner, A., M.Latif and B. Schneider, 2005 Future Climate: Models

Latif, M. et al, 2000

Rapid climate change in the media “Britain faces big freeze as Gulf Stream loses strength” The Times (Britain), Dec 2005 “Failing ocean current raises fears of mini ice age” New Scientist, Nov 2005 “Shifting currents renew fears of freezing” The Montreal Gazette, Dec 2005

Summary Possible reasons for past rapid climate change –Sea ice formation in North Atlantic –Lake Agassiz Model predictions for the future –Models predict gradual changes in THC without a rapid shutdown –Increased salinity may compensate for density decreases in Atlantic Ocean

References CCNet Denton, G.H., et al, The role of seasonality in abrupt climate change. Quaternary Science Reviews, 24, Gregory, J.M., et al, A model intercomparison of changes in the Atlantic thermohaline circulation in response to increasing atmospheric CO2 concentration. Geophysical Research Letters, 32, L Latif, M. et al, Tropical stabilization of the thermohaline circulation in a greenhouse warming simulation. Journal of Climate, 13, Schmittner, A., M. Latif and B. Schneider, Model projections of the North Atlantic thermohaline circulation for the 21st century assessed by observations. Geophysical Research Letters, 32, L Teller, J.T. and D.W. Leverington, Glacial Lake Agassiz: A 5000 yr history of change and its relationship to the d18O record of Greenland. GSA Bulletin, 116,

Gregory JM et al, 2005