Arctic's 'Last Ice Area' at Rising Risk Amid Climate Crisis, Scientist Says

As climate changes, multi-year ice arches melt earlier, putting polar bears and other life in peril.
Brad Bergan

Squeezed against Greenland and the upper edges of the Canadian Arctic Archipelago remains the oldest and thickest body of sea ice in the world — covering the ocean for hundreds of thousands of square miles.

Commonly known in scientific communities as "the last ice area," the region expected to endure even the highest projected arctic temperatures and provide a vital refuge for walruses, polar bears, and other species may be in peril, according to a recent study published in the journal Nature.


Arctic's 'last ice area' in peril amid climate crisis

The recent research — from the University of Toronto Mississauga — suggests this "last ice area" is in more trouble than scientists initially thought. In the paper, Professor Kent Moore and his co-authors explain how the multi-year ice phenomenon is at risk not only from melting in place, but also floating southward, into warmer waters.

This south-bound ice would create an "ice deficit" — accelerating the disappearance of ice from this final frozen frontier.

"This very old ice is what we're concerned about," said Moore, of U of T's chemical and physical sciences department. "The hope is that this area will persist into the middle part of this century or even longer. And then, hopefully, we'll eventually be able to cool the planet down. The ice will start growing again, and then this area can act as a sort of seed."

'Last ice area' losing ice mass of twice rate of entire Arctic

With the help of satellite data, Moore has studied ice arches forming along the Nares Strait — a roughly 25-mile-wide (40-km-wide), 370-mile long (600-km-long) channel running between Ellesmere Island and Greenland, from Baffin Bay to the Arctic Ocean.

More had already seen worrying trends in previous research — indicating the ice region is on the move now more so than ever observed before.

"The last ice area is losing ice mass at twice the rate of the entire Arctic," said Moore. "We realized this area may not be as stable as people think."

Ice arches play vital role in Nares Strait

Moore's most recent analysis of available satellite data suggests the problem is exacerbating. Arches along the Nares Strait — which typically hold the "Last Ice Area" in place have lost stability, according to the study.

"The ice arches that usually develop at the northern and southern ends of Nares Strait play an important role in modulating the export of Arctic Ocean multi-year sea ice," Moore and his co-authors wrote.

ESA Sentinel-2
Comparative images of the ice arch forming in June and July 2020. Source: Sentinel-2 Satellite / European Space Agency

More than twice the length of Louisiana Pontchartrain Causeway

"The duration of arch formation has decreased over the past 20 years, while the mass of ice exported through Nares Strait has increased," added Moore and colleagues in the study, reports

Ice arches in the region form when weather cools. Several ice floes converge when they're funneled into the comparatively narrow strait, clumping into massive structures — which look like bridge supports tipped into their sides. The ice arches extend across the full width of the passage, preventing multi-year ice on the north and south tips of the passage from moving.

"It's really quite profound to imagine a 100-kilometer-long barrier of ice that remains stationary for months at a time. That's more than twice as long as Louisiana's Lake Pontchartrain Causeway — the world's longest continuous bridge over water," said Moore. "It speaks to the strength of ice."

Arctic ice thinning, climate changing, polar bears in peril

However, this icy strength won't cut it for long. Ice arches only coalesce once per year, and once broken up in the spring, regional ice may move more freely down the Nares Strait. The observed change lies in this happening sooner than it has in the past.

"Every year, the reduction in duration is about one week," added Moore. "They used to persist for about 200 days and now they're persisting for about 150 days. That's quite a remarkable reduction."

"We think that it's related to the fact the ice is just thinner[,] and thinner ice is less stable," said Moore.

Beyond the photogenic loss of a pristine frozen horizon, multiple arctic-native animal species like polar bears may lose a habitat — in addition to ice algae, which forms below the ice and in brine channels piercing through its fissures and cracks and providing oxygen, carbon, and nutrients crucial to the complex yet vulnerable ecosystem.

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