Continued melting of Arctic ice in the coming decades could contribute to further weakening of the ‘great ocean conveyor’, a complex pattern of water currents that are driven by the interactions between surface heat and salinity.
The Atlantic meridional overturning circulation (AMOC) provides a key source of uncertainty regarding future climate change. Maps of temperature trends over the twentieth century show a conspicuous region of cooling in the northern Atlantic. We present multiple lines of evidence suggesting that this cooling may be due to a reduction in the AMOC over the twentieth century and particularly after 1970.
Since 1990 the AMOC seems to have partly recovered. This time evolution is consistently suggested by an AMOC index based on sea surface temperatures, by the hemispheric temperature difference, by coral-based proxies and by oceanic measurements. In this seminar, Professor Rahmstorf will discuss a possible contribution of the melting of the Greenland Ice Sheet to the slowdown. Using a multi-proxy temperature reconstruction for the AMOC index suggests that the AMOC weakness after 1975 is an unprecedented event in the past millennium (p>0.99).
About the Speaker
Stefan Rahmstorf is Professor of Physics of the Oceans at Potsdam University and Department Head at the Potsdam Institute for Climate Impact Research. He is also Fellow of the American Geophysical Union Honorary Fellow of the University of Wales/Bangor Member of the Academia Europaea. His most recent book is The Climate Crisis.