Carsten Rühlemann
Carsten Rühlemann is a researcher at the MARUM research centre at the University of Bremen in Germany. Researchers at MARUM study the oceans’ impact on the planet. Mr Rühlemann works in the Marine Geology division, specializing in ocean currents and their interaction with global climate. He has recently been studying the importance of alkenones in oceans. Mr Rühlemann has also worked extensively on the reconstruction of past surface and deep-ocean currents.
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Susan Lieberman is Deputy Director of The Pew Environment Group and head of the Cites Pew Delegation at the CITES summit in Doha.
Fred Pearce is journalist specialized in the environment and development. He was born in the United Kingdom and studied geography in the University of Cambridge. His latest book is When the Rivers...
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The Food and Agriculture Organization of the United Nations (FAO) is a specialized agency of the United Nations. It was founded on 16 October 1945 in Quebec City, Quebec, Canada. In 1951 its...
Carsten Rühlemann is a researcher at the MARUM research centre at the University of Bremen in Germany. Researchers at MARUM study the oceans’ impact on the planet. Mr Rühlemann works in the Marine...
Richard Seager has been a researcher at the University of Columbia’s Lamont-Doherty Earth Observatory (New York) since 1992, studying the influence of tropical atmosphere-ocean interactions on...
Peter U. Clark has been a researcher in the Department of Geosciences at Oregon State University since 1988. He specializes in glacial geography, quaternary stratigraphy and paleoclimatology. Mr...
Warming of the tropical Atlantic Ocean and slowdown of thermohaline circulation during the last deglaciation
05/09/2008 2:18 pm
Evidence for abrupt climate changes on millennial and shorter timescales is widespread in marine and terrestrial climate records. Rapid reorganization of ocean circulation is considered to exert some control over these changes, as are shifts in the concentrations of atmospheric greenhouse gases. The response of the climate system to these two influences is fundamentally different: slowing of thermohaline overturn in the North Atlantic Ocean is expected to decrease northward heat transport by the ocean and to induce warming of the tropical Atlantic, whereas atmospheric greenhouse forcing should cause roughly synchronous global temperature changes. So these two mechanisms of climate change should be distinguishable by the timing of surfacewater temperature variations relative to changes in deep-water circulation. […]
We find significant warming is documented for Heinrich event H1 (16,900-15,400 calendar years BP) and the Younger Dryas event (12,900-11,600 cal. Yr BP), which were periods of intense cooling in the northern North Atlantic. Temperature changes in the tropical and high-latitude North Atlantic are out of phase, suggesting that the thermohaline circulation was the important trigger for these rapid climate changes. In the high northern latitudes, the last deglaciation was punctuated by several brief returns to near-glacial climate. The most prominent of these events was the Younger Dryas cold period.
Carsten RUHLEMANN, Stefan MULITZA, Peter J. MULLER, Gerold WEFER & Rainer ZAHN
Ocean NATURE vol. 402
1999 December 2
www.nature.com
© 1999 Macmillan Magazines Lt
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