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New Study: Arctic Waters Were 4°C Warmer Than Today And Nearly Sea-Ice Free Year-Round ~4100 Years Ago

New Study: Arctic Waters Were 4°C Warmer Than Today And Nearly Sea-Ice Free Year-Round ~4100 Years Ago

Today, the region north of Svalbard is encrusted with sea ice for all but a few weeks per year and summer sea surface temperatures (SSTs) hover near 0°C. Scientists (Brice et al., 2020) have determined this same region had sea ice-free conditions last about 10 months per year while SSTs reached 4°C just ~4100 years ago.

In early September, 2019, Arctic explorers once again needed to be rescued from the “disappearing” sea ice that had captured their ship in central Svalbard. This region is presently free of sea ice for only a few weeks per year (late August).

Image Source:

Observational measurements (Rösel et al., 2018) of the sea ice north of Svalbard indicate the ice has actually been significantly thicker in recent years (1.56 to 1.65 meters in 2015, 2017) than it was in 1955 (0.94 of a meter).

Image Source: Rösel et al., 2018

A study site northeast of Svalbard (Brice et al., 2020) reveals today’s sea surface temperatures of “<0°C” are at least 4°C colder than they were just a few thousand years ago, when the Arctic was sea ice free for all but “a couple of months” every year. Notice the graphics that show today’s sea ice monthly duration (~11 months per year) and summer sea surface temperatures (zero degrees Celsius) are among the highest and lowest (respectively) of the Holocene.

Image Source: Brice et al., 2020

Per Brice et al. (2020), the much warmer Arctic climate and absence of sea ice reached an “optimum” during “the interval around 3000-2000 cal yr BP” such that late Stone Age human settlements north of Svalbard were “feasible”.

“Although our core was collected offshore, far from human settlement, the data compiled here and the reconstruction we propose provide some clues on the regional climate and marine environment history. Hence, our study yields some information about the fact that the interval around 3000–2000 cal yr BP was probably the most favorable time window of the Holocene for human occupation in the area of northern Svalbard. Such a finding does not support directly the hypothesis of Stone Age settlements in Svalbard proposed by Christiansson and Simonsen (1970) but provides a climatological and oceanographical framework that would make it feasible.”