GFZ German research centre for geo sciences

Climate History of the Arctic as a Key to the Future

Climate History of the Arctic as a Key to the Future
09.05.2013|Potsdam: Analyses of the longest continental sediment core ever collected in the Arctic have provided an almost continuous archive of information on arctic climate dynamics for the period from 3.6 to 2.2 million years ago. It was during this period that a transition took place from the warm Pliocene to the Quaternary, the so-called Ice Age, in which we live today and through which the polar region, which undergoes glacial /interglacial cycles with varying ice coverage, is characterized.

09.05.2013 | Potsdam: Analyses of the longest continental sediment core ever collected in the Arctic have provided an almost continuous archive of information on arctic climate dynamics for the period from 3.6 to 2.2 million years ago. It was during this period that a transition took place from the warm Pliocene to the Quaternary, the so-called Ice Age, in which we live today and through which the polar region, which undergoes glacial /interglacial cycles Analyses of the longest continental sediment core ever collected in the Arctic have provided an almost continuous archive of information on arctic climate dynamics for the period from 3.6 to 2.2 million years ago. It was during this period that a transition took place from the warm Pliocene to the Quaternary, the so-called Ice Age, in which we live today and through which the polar region, which undergoes glacial /interglacial cycles with varying ice coverage, is characterized. 

 

The new data clearly demonstrate that the thawing of the Northern Hemisphere occurred in different stages and was not continuous,” explains Prof. Martin Melles, who is coordinating the work of the German scientists at the University of Cologne. “This has been indicated in other studies; for the first time, this transition is documented for a period of more than one million years without gaps in the sediment layers of Lake El’gygytgyn.” 

 

The study, which is published in the current edition of Science Express (Nr. 1233137; 09.05.2013), documents this using sediment cores from the Siberian lake El’gygytgyn.

This 170 meter deep lake is located 100 kilometres north of the Arctic Circle in Chukotka, on the north coast of Siberian. Due to the low temperatures and the permafrost which only thaws superficially during the short summer there, the catchment area of the lake is characterized by a sparse Tundra vegetation of grass and small bushes. The lake was formed 3.6 million years ago when a meteorite, perhaps a kilometre in diameter, hit the Earth and blasted out an 11-mile (18 km) wide crater. 

 

At that time, the Northern Hemisphere was ice-free and the area around the lake was forested. It was only after about one million years, with the onset of the Quaternary, that the Arctic began to freeze. “In the sediments that have been deposited undisturbed annually since its formation, the eventful climate and environmental history of this region has been recorded in great detail, like in a book,” explains Dr. habil. Norbert Nowaczyk from the GFZ German Research Centre for Geosciences. “Using modern analysis technology and new processes we have been able to read this history page for page.” 

 

It is now known that the first stages of freezing began 3.3 million years ago. Using the pollen that gathered in the sediments, a picture can be painted of past temperatures and precipitation since the formation of the lake. 

 

It is amazing to think that the temperatures even during the first stages of freezing were similar to those of today,” says Dr. Catalina Gebhardt from the Alfred Wegener Institute (AWI) in Bremerhaven. “And up to about 2.2 million years ago, it was significantly warmer than before Industrialization.” 

 

As is known from cores from sea sediments, the conditions in the North Pacific have changed significantly over time. “Up until now many scientists assumed that glaciation intensified with this,” explains Melles. “At Lake El’gygytgyn, we observed that at this time precipitation decreased significantly, while temperatures fell more gradually in stages. The glacial/inter-glacial cycles that we know from the most recent past only developed about 1.8 million years ago.” 

 

In the winter of 2009, an international team of scientists drilled sediment cores from the ice covered lake and brought a 300 meter long sediment archive back to Germany. The sediments then underwent chemical, physical and biological analyses. The publication this week is the second publication in the journal Science on the El’gygytgyn Drilling Project. “This latest paper completes our goal of providing an overview of new knowledge of the evolution of Arctic change across the western borderlands back to 3.6 million years and places this record into a global context with comparisons to records in the Pacific, the Atlantic and Antarctica,” Melles points out. 

 

Brigham-Grette J., Melles M., Minyuk P., Andreev A., Tarasov P., DeConto R., Koenig S., Nowaczyk N., Wennrich V., Rosén P., Haltia-Hovi E., Cook T., Gebhardt C., Meyer-Jacob C., Snyder J., Herzschuh U. (2013): Pliocene Warmth, extreme Polar Amplification, and Stepped Pleistocene Cooling recorded in NE Russia. - Science Express, 1233137, 09.05.2013.

 

The International Lake El'gygytgyn Drilling Project was funded by the International Continental Drilling Program (ICDP), the U.S. National Science Foundation’s Division of Earth Sciences and Office of Polar Programs, the German Federal Ministry for Education and Research, Alfred Wegener Institute, GeoForschungsZentrum-Potsdam, the Russian Academy of Sciences Far East Branch, the Russian Foundation for Basic Research and the Austrian Ministry for Science and Research. Additional funding for the evaluation of data was provided by the German Research Foundation (DFG).

 

Contact:

University of Cologne

Martin Melles

+49-221-470-2262 (office)

+49-160-719-2657 (mobile)

mmelles@uni-koeln.de

 

GFZ German Research Centre for Geosciences

Dr. habil. Norbert Nowaczyk

Tel.: +49 331 288 1369 

norbert.nowaczyk@gfz-potsdam.de

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