Arctic Ice

New analysis finds the Arctic’s oldest and thickest ice is extra cell and is vanishing twice as quick as ice in the remainder of the Arctic. Credit score: NOAA

The oldest and thickest Arctic sea ice is disappearing twice as quick as ice in the remainder of the Arctic Ocean, in accordance with new analysis.

A new study in AGU’s journal Geophysical Analysis Letters finds ice within the Arctic Ocean north of Greenland is extra cell than beforehand thought, as ocean currents and atmospheric winds are probably transporting the previous, thick ice discovered there to different components of the Arctic. As a end result, ice mass within the space – the final place researchers assume will lose its year-round ice cowl – is declining twice as quick as ice in the remainder of the Arctic, in accordance with the brand new findings.

Local weather fashions predict Arctic summers will quickly be ice-free – maybe as early as 2030 – that means lower than 1 million sq. kilometers (386,000 sq. miles) of summer season sea ice will blanket the Arctic Ocean. Arctic warming has already created an setting which results in youthful sea ice.

Most ice masking the Arctic is just one to 4 years previous, in accordance with the Nationwide Snow and Ice Information Heart. As skinny, younger ice melts in future summers, solely a 2,000-kilometer (1,240-mile) arc of ice will stay, stretching from the western Canadian Arctic Archipelago to Greenland’s northern coast. On this slice of the Arctic, which specialists name the Last Ice Space, sea ice is greater than 5 years previous and might measure greater than 4 meters (13 toes) thick.

The brand new analysis suggests the Last Ice Space is a dynamic place encompassing two sub-regions the place ice thickness fluctuates by 1.2 meters (four toes) from yr to yr. Ice is turning into thinner in two distinct subregions, that are shedding 0.four meters (1.three toes) of ice thickness per decade, amounting to a 1.5-meter (5 foot) lack of ice for the reason that late 1970s, in accordance with the brand new research.

“We can’t treat the Last Ice Area as a monolithic area of ice which is going to last a long time,” stated Kent Moore, an atmospheric physicist on the College of Toronto in Canada and lead creator of the brand new research. “There’s actually lots of regional variability.”

Arctic Ocean Annual Mean Sea Ice Thickness

Annual imply sea ice thickness (m) over the Arctic Ocean from 1979 – 2018. The black line surrounds the world the place the ice thickness exceeds three m and may be thought-about because the area referred to as the Last Ice Space. The white strains encompass the 2 areas the place the ice thickness exceeds 4m. Credit score: Kent Moore/College of Toronto.

For wildlife who depend on sea ice for survival, the Last Ice Space presents a sanctuary, and is the ultimate place they will retreat to in a warming world. Understanding how the Last Ice Space modifications all year long may assist pinpoint which spots are greatest suited to supply a refuge for wildlife who’re depending on sea ice, in accordance with the research’s authors.

Locations with much less ice motion, for instance, could present extra appropriate circumstances for a wildlife sanctuary, because the ice will stay longer. The brand new research presents context for policymakers to think about after they set up protected areas within the Arctic, Moore stated.

“Eventually the Last Ice Area will be the region that will repopulate the Arctic with wildlife,” Moore stated. “If we lose all the ice, we lose those species. This area will be a refuge where species can survive and hopefully expand their regions once the ice starts returning.”

A dynamic zone

The Last Ice Space is dwelling to the Arctic’s oldest and thickest ice as a result of ocean currents and atmospheric winds carry patches of floating ice in a round sample. These blocks of ice crash into one another and pile up alongside the northern edges of Greenland and Canada. Researchers, nevertheless, know little about how ice on this area strikes and melts throughout the yr.

This lack of know-how prompted Moore and his colleagues to trace modifications within the Last Ice Space. Within the new research, the staff modeled sea ice cowl, thickness and movement throughout the zone from 1979 to 2018. Their mannequin, primarily based on satellite tv for pc observations and atmospheric knowledge, revealed two areas with distinct seasonal and inter-annual fluctuations – one to the east and one to the west.

In each areas, sea ice was thinner and lined much less space in the summertime and early fall than within the Arctic winter, although ice thickness within the west tended to hit its minimal earlier within the season. Ice movement within the jap portion of the Last Ice Space seemed to be extra secure. Western ice – managed by winds blowing clockwise – has begun transferring sooner, which might be the results of thinning ice.

In response to Moore, the lack of ice within the Last Ice Space is probably going on account of ice motion out of the area, notably within the west. If sea ice is thinner and transferring sooner, items on the margins will movement first into the open ocean, adopted by bigger bits from the middle, like a giant site visitors jam.

“Historically, we thought of this place as an area that just receives ice,” stated David Barber, an Arctic climatologist from the College of Manitoba in Canada who was not concerned within the new research. “But these results are teaching us that this is a dynamic area.”

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Reference: “Spatiotemporal Variability of Sea Ice in the Arctic’s Last Ice Area” by G. W. Ok. Moore, A. Schweiger, J. Zhang and M. Steele, 15 October 2019, Geophysical Analysis Letters.
DOI: 10.1029/2019GL083722



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