Pliocene Warmth, Polar Amplification, and Stepped Pleistocene Cooling Recorded in NE Arctic Russia
- Julie Brigham-Grette1,*,
- Martin Melles2,
- Pavel Minyuk3,
- Andrei Andreev2,
- Pavel Tarasov4,
- Robert DeConto1,
- Sebastian Koenig1,
- Norbert Nowaczyk5,
- Volker Wennrich2,
- Peter Rosén6,
- Eeva Haltia5,†,
- Tim Cook7,
- Catalina Gebhardt8,
- Carsten Meyer-Jacob6,
- Jeff Snyder9,
- Ulrike Herzschuh10
- 1Department of Geosciences, University of Massachusetts, 611 North Pleasant Street, Amherst, MA 01003, USA.
- 2Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Strasse 49a, D-50674 Cologne, Germany.
- 3North-East Interdisciplinary Scientific Research Institute, Far East Branch of the Russian Academy of Sciences, Portovaya Street 16, 685000 Magadan, Russia.
- 4Free University Berlin, Institute of Geological Sciences, Malteser Strasse 74-100, Haus D, D-12249 Berlin, Germany.
- 5Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, D-14473 Potsdam, Germany.
- 6Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden.
- 7Department of Physical and Earth Sciences, Worcester State University, Worcester, MA 01602, USA.
- 8Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, D-27570 Bremerhaven, Germany.
- 9Department of Geology, Bowling Green State University, OH 43403, USA.
- 10Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, D-14473 Potsdam, Germany.
- ↵*Corresponding author. E-mail: juliebg{at}geo.umass.edu
From Russia with Lovely Data
Climate and the atmospheric concentration of CO2 are closely linked. Brigham-Grette et al. (p. 1421, published online 9 May) present data from Lake El'gygytgyn, in northeast Arctic Russia, that shows how climate varied between 3.6 and 2.2 million years ago, an important interval in the global cooling trend that accelerated rapidly at the end of the Miocene. Summer temperatures were about 10°C warmer than today, even though the concentration of atmospheric CO2 was similar.
Abstract
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°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.
- Received for publication 23 November 2012.
- Accepted for publication 24 April 2013.
