Peter U. Clark et al., Science, Vol. 325, No. 5941 (2009): The Last Glacial Maximum

Science, Vol. 325, No. 5941 pp. 710-714 (7 August 2009); DOI: 10.1126/science.1172873

The Last Glacial Maximum

Peter U. Clark,^1,* Arthur S. Dyke,² Jeremy D. Shakun,¹ Anders E. Carlson,³ Jorie Clark,¹ Barbara Wohlfarth,⁴ Jerry X. Mitrovica,⁵ Steven W. Hostetler,⁶ and A. Marshall McCabe⁷

Abstract

We used 5704 ¹⁴C, ¹⁰Be, and ³He ages that span the interval from 10,000 to 50,000 years ago (10-50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO₂. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19-20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19-20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level ~14.5 ka.

Link to abstract: http://www.sciencemag.org/cgi/content/abstract/325/5941/710