Science & Technology

Last Ice-Covered Parts of Summertime Arctic Ocean – a Refuge for Polar Bears, Seals, Walruses – Vulnerable to Climate Change

This picture of sea ice on the Wandel Sea north of Greenland was taken August 16, 2020, from the German icebreaker Polarstern, which handed by way of the realm as half of the year-long MOSAiC Expedition. This space used to stay absolutely coated in ice all year long. Satellite tv for pc photographs present that August 14, 2020, was a report low sea ice focus for this area, at 50%. Credit score: Felix Linhardt/Kiel College

In a quickly altering Arctic, one space would possibly function a refuge – a place that would proceed to harbor ice-dependent species when circumstances in close by areas change into inhospitable. This area north of Greenland and the islands of the Canadian Arctic Archipelago has been termed the Last Ice Space. However analysis led by the College of Washington means that components of this space are already exhibiting a decline in summer time sea ice.

Last August, sea ice north of Greenland confirmed its vulnerability to the long-term results of local weather change, in accordance to a research printed on July 1, 2021, within the open-access journal Communications Earth & Atmosphere.

“Present considering is that this space will be the final refuge for ice-dependent species. So if, as our research exhibits, it could be extra susceptible to local weather change than folks have been assuming, that’s vital,” stated lead creator Axel Schweiger, a polar scientist on the UW Utilized Physics Laboratory.

How the final ice-covered areas will fare issues for polar bears that use the ice to hunt for seals that use the ice for constructing dens for their younger, and for walruses that use the ice as a platform for foraging.

A polar bear is perched on a thick chunk of sea ice north of Greenland in March 2016. These thicker, older items of sea ice don’t absolutely shield the bigger area from dropping its summer time ice cowl. Credit score: Kristin Laidre/College of Washington

“This space has lengthy been anticipated to be the first refuge for ice-dependent species as a result of it’s one of the final locations the place we anticipate summer time sea ice to survive within the Arctic,” stated co-author Kristin Laidre, a principal scientist on the UW Utilized Physics Laboratory.

The research targeted on sea ice in August 2020 within the Wandel Sea, an space that used to be coated year-round in thick, multiyear ice.

“Sea ice circulates by way of the Arctic, it has a specific sample, and it naturally finally ends up piling up towards Greenland and the northern Canadian coast,” Schweiger stated. “In local weather fashions, if you spin them ahead over the approaching century, that space has the tendency to have ice survive in the summertime the longest.”

Like different components of the Arctic Ocean, the ice right here has been regularly thinning, although final spring’s sea ice within the Wandel Sea was on common barely thicker than earlier years. However satellite tv for pc photographs confirmed a report low of simply 50% sea ice focus on Aug. 14, 2020.

The research regarded on the Wandel Sea north of Greenland, which is inside what’s referred to as the “Last Ice Space” of the Arctic Ocean. Credit score: Schweiger et al./Communications Earth & Atmosphere

The brand new research makes use of satellite tv for pc knowledge and sea ice fashions to decide what brought about final summer time’s report low. It finds that about 80% was due to weather-related components, like winds that break up and transfer the ice round. The opposite 20%, or one-fifth, was from the longer-term thinning of the ocean ice due to world warming.

The mannequin simulated the interval from June 1 to Aug. 16 and located that uncommon winds moved sea ice out of the realm, however that the multiyear thinning development additionally contributed, by permitting extra daylight to heat the ocean. Then, when winds picked up, this heat water was ready to soften the close by ice floes.

The record-low ice focus in 2020 was stunning as a result of the typical ice thickness firstly of summer time was really shut to regular.

“Throughout the winter and spring of 2020 you had patches of older, thicker ice that had drifted into there, however there was sufficient thinner, newer ice that melted to expose open ocean,” Schweiger stated. “That started a cycle of absorbing warmth vitality to soften extra ice, in spite of the truth that there was some thick ice. So in years the place you replenish the ice cowl on this area with older and thicker ice, that doesn’t appear to assist as a lot as you would possibly anticipate.”

The outcomes increase issues concerning the Last Ice Space however can’t instantly be utilized to the complete area, Schweiger stated. Additionally unknown is how extra open water on this area would have an effect on ice-dependent species over the brief and lengthy phrases.

“We all know little or no about marine mammals within the Last Ice Space,” stated Laidre, who can be an affiliate professor within the College of Aquatic and Fishery Sciences. “We’ve nearly no historic or present-day knowledge, and the truth is that there are a lot extra questions than solutions concerning the future of these populations.”

Reference: “Accelerated sea ice loss within the Wandel Sea factors to a change within the Arctic’s Last Ice Space” by Axel J. Schweiger, Michael Steele, Jinlun Zhang, G. W. Okay. Moore and Kristin L. Laidre, 1 July 2021, Communications Earth & Atmosphere.
DOI: 10.1038/s43247-021-00197-5

Different co-authors are Michael Steele and Jinlun Zhang on the UW; and Kent Moore on the College of Toronto. The analysis was funded by the U.S. Nationwide Science Basis, NASA, the Pure Sciences and Engineering Analysis Council of Canada; the Nationwide Oceanic and Atmospheric Administration; the Workplace of Naval Analysis; and the World Wildlife Fund Canada.
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