Ice-shelf collapse from subsurface warming as a trigger for Heinrich events
| Autor: | Laurie Padman, Shaun A. Marcott, Gary P. Klinkhammer, Feng He, June Padman, Anders E. Carlson, Jun Cheng, Peter U. Clark, Zhengyu Liu, Andreas Schmittner, S. R. Springer, Bette L. Otto-Bliesner, Andy Ungerer |
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| Rok vydání: | 2011 |
| Předmět: |
Greenhouse Effect
010504 meteorology & atmospheric sciences Climate Oceans and Seas Ice stream Foraminifera 010502 geochemistry & geophysics 01 natural sciences Ice shelf Water Movements medicine Magnesium Ice Cover Letters Greenhouse effect Collapse (medical) abrupt climate change 0105 earth and related environmental sciences geography Multidisciplinary geography.geographical_feature_category biology paleoclimatology Temperature biology.organism_classification Oceanography 13. Climate action Benthic zone Climatology paleoceanography Physical Sciences Abrupt climate change Calcium medicine.symptom Ice sheet Geology |
| Zdroj: | Proceedings Of The National Academy Of Sciences Of The United States Of America (0027-8424) (Natl Acad Sciences), 2011-08, Vol. 108, N. 33, P. 13415-13419 |
| ISSN: | 1091-6490 0027-8424 |
| Popis: | Episodic iceberg-discharge events from the Hudson Strait Ice Stream (HSIS) of the Laurentide Ice Sheet, referred to as Heinrich events, are commonly attributed to internal ice-sheet instabilities, but their systematic occurrence at the culmination of a large reduction in the Atlantic meridional overturning circulation (AMOC) indicates a climate control. We report Mg/Ca data on benthic foraminifera from an intermediate-depth site in the northwest Atlantic and results from a climate-model simulation that reveal basin-wide subsurface warming at the same time as large reductions in the AMOC, with temperature increasing by approximately 2 °C over a 1–2 kyr interval prior to a Heinrich event. In simulations with an ocean model coupled to a thermodynamically active ice shelf, the increase in subsurface temperature increases basal melt rate under an ice shelf fronting the HSIS by a factor of approximately 6. By analogy with recent observations in Antarctica, the resulting ice-shelf loss and attendant HSIS acceleration would produce a Heinrich event. |
| Databáze: | OpenAIRE |
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