Publication Date:
2013-05-11
Description:
Understanding the evolution of Arctic polar climate from the protracted warmth of the middle Pliocene into the earliest glacial cycles in the Northern Hemisphere has been hindered by the lack of continuous, highly resolved Arctic time series. Evidence from Lake El'gygytgyn, in northeast (NE) Arctic Russia, shows that 3.6 to 3.4 million years ago, summer temperatures were ~8 degrees C warmer than today, when the partial pressure of CO2 was ~400 parts per million. Multiproxy evidence suggests extreme warmth and polar amplification during the middle Pliocene, sudden stepped cooling events during the Pliocene-Pleistocene transition, and warmer than present Arctic summers until ~2.2 million years ago, after the onset of Northern Hemispheric glaciation. Our data are consistent with sea-level records and other proxies indicating that Arctic cooling was insufficient to support large-scale ice sheets until the early Pleistocene.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Brigham-Grette, Julie -- Melles, Martin -- Minyuk, Pavel -- Andreev, Andrei -- Tarasov, Pavel -- DeConto, Robert -- Koenig, Sebastian -- Nowaczyk, Norbert -- Wennrich, Volker -- Rosen, Peter -- Haltia, Eeva -- Cook, Tim -- Gebhardt, Catalina -- Meyer-Jacob, Carsten -- Snyder, Jeff -- Herzschuh, Ulrike -- New York, N.Y. -- Science. 2013 Jun 21;340(6139):1421-7. doi: 10.1126/science.1233137. Epub 2013 May 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Geosciences, University of Massachusetts, 611 North Pleasant Street, Amherst, MA 01003, USA. juliebg@geo.umass.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23661643" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
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Chemistry and Pharmacology
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Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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