Title |
The Last Glacial Maximum
|
---|---|
Published in |
Science, August 2009
|
DOI | 10.1126/science.1172873 |
Pubmed ID | |
Authors |
Peter U. Clark, Arthur S. Dyke, Jeremy D. Shakun, Anders E. Carlson, Jorie Clark, Barbara Wohlfarth, Jerry X. Mitrovica, Steven W. Hostetler, A. Marshall McCabe |
Abstract |
We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 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 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 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 approximately 14.5 ka. |
X Demographics
Geographical breakdown
Country | Count | As % |
---|---|---|
United States | 2 | 40% |
Chile | 1 | 20% |
Unknown | 2 | 40% |
Demographic breakdown
Type | Count | As % |
---|---|---|
Members of the public | 2 | 40% |
Science communicators (journalists, bloggers, editors) | 1 | 20% |
Practitioners (doctors, other healthcare professionals) | 1 | 20% |
Scientists | 1 | 20% |
Mendeley readers
Geographical breakdown
Country | Count | As % |
---|---|---|
United States | 30 | 1% |
United Kingdom | 11 | <1% |
Canada | 9 | <1% |
Germany | 7 | <1% |
Brazil | 6 | <1% |
Portugal | 5 | <1% |
Chile | 4 | <1% |
France | 3 | <1% |
Switzerland | 3 | <1% |
Other | 44 | 2% |
Unknown | 2359 | 95% |
Demographic breakdown
Readers by professional status | Count | As % |
---|---|---|
Student > Ph. D. Student | 598 | 24% |
Researcher | 393 | 16% |
Student > Master | 339 | 14% |
Student > Bachelor | 268 | 11% |
Student > Doctoral Student | 111 | 4% |
Other | 410 | 17% |
Unknown | 362 | 15% |
Readers by discipline | Count | As % |
---|---|---|
Earth and Planetary Sciences | 998 | 40% |
Agricultural and Biological Sciences | 443 | 18% |
Environmental Science | 268 | 11% |
Biochemistry, Genetics and Molecular Biology | 102 | 4% |
Arts and Humanities | 71 | 3% |
Other | 160 | 6% |
Unknown | 439 | 18% |