Kiel (global-adventures.us): Never before in the past 2,000 years was the Atlantic water in the Fram Strait between Greenland and Svalbard as warm as today, a study of marine sediments from the western Svalbard continental margin concludes. The recent decrease in sea ice coverage and the rapid warming of the Arctic are a result of the enhanced heat transfer from the Atlantic; the study published in the journal Science says.
The Fram Strait between Greenland and Svalbard (Spitsbergen) is the major connection between the Arctic Ocean and the Norwegian-Greenland and Barents Seas. In its eastern part, relatively warm and saline water masses from the North Atlantic enter the Arctic. The northernmost extension of the Gulf Stream provides ice-free conditions in the waters west of Svalbard even in winter.
led by scientists from the Leibniz Institute of Marine Sciences (IFM-GEOMAR) and the Academy of Sciences, Humanities, and Literature Mainz, analyzed marine sediments from the western Fram Strait and found that temperatures of the northward inflowing Atlantic Water varied several tenths of a degree Celsius during the past 2,000 years. The most recent temperature increase of approximately two degrees Celsius is unprecedented in the time period. “Such a warming of the Atlantic Water in the Fram Strait significantly differs from all climate variations in the past 2,000 years”, says Dr. Robert Spielhagen, IFM-GEOMAR scientists and the lead author of the study.
Since continuous meteorological and oceanographic data extend only for about 150 years in the past. After that scientists used ice and sediment cores to determine past oceanic and climatic conditions. The chemical composition of the sediment allowed the team to determine the water temperature in which the organisms lived. The researchers were able to identify several warm and cool intervals in the Fram Strait during the past 2,000 years.
One of these
intervals was the ‘Little Ice Age’ from the mid-15th to the late 19th century. When it was unusually cold says co-author Kirstin Werner. “Today, temperatures of the Atlantic Water in the Fram Strait are approximately 1.5 degrees higher than during the climatically warm early Medieval Period. We assume that the accelerated decrease of the Arctic sea ice cover. The warming of ocean and atmosphere in the Arctic, as measured during the past decades. They are in part related to an increased heat transfer from the Atlantic”, says Spielhagen.
The illustration shows a bathymetric map of the Norwegian-Greenland Sea and Arctic Ocean. White shading marks average summer sea ice cover. White arrows mark ice drift directions. Red arrows mark warm Atlantic Water entering the Arctic where it submerges under the cold, ice-covered surface layer.
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