The role of seasonality in abrupt climate change

被引:415
作者
Denton, GH
Alley, RB [1 ]
Comer, GC
Broecker, WS
机构
[1] Penn State Univ, Dept Geosci, University Pk, PA 16802 USA
[2] Penn State Univ, Earth & Environm Syst Inst, University Pk, PA 16802 USA
[3] Univ Maine, Dept Earth Sci, Orono, ME 04469 USA
[4] Univ Maine, Climate Change Inst, Orono, ME 04469 USA
[5] GCI, Waukesha, WI 53186 USA
[6] Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA
基金
美国国家科学基金会;
关键词
D O I
10.1016/j.quascirev.2004.12.002
中图分类号
P9 [自然地理学];
学科分类号
0705 ; 070501 ;
摘要
A case is made that seasonality switches dominated by wintertime were instrumental in abrupt climate changes in the North Atlantic region during the last glaciation and into the Holocene. The primary evidence comes from mismatches between mean annual temperatures from Greenland ice cores in comparison with snowline changes in East Greenland, northern Europe, and North America. The most likely explanation is a shutdown (or reduction in strength) of the conveyor. This allows the spread of winter sea ice across the North Atlantic, thus causing the northern region to experience much colder winters. Because they mimic the Greenland temperature rather than the snowline signal, changes in the Atlantic Intertropical Convergence Zone and the Asian monsoon may also share a winter linkage with Greenland. Thus the paleoclimate record is consistent with the notion that a huge continental sector of the Northern Hemisphere, stretching from Greenland to Asia, was close to an extreme winter threshold during much of the last glaciation. Winter climate crossed this threshold repeatedly, with marked changes in seasonality that may well have amplified and propagated a signal of abrupt change throughout the hemisphere and into the tropics. (c) 2005 Published by Elsevier Ltd.
引用
收藏
页码:1159 / 1182
页数:24
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