Oldest Arctic sea ice vanishes twice as fast as rest of region, study shows

New research finds the Arctic’s oldest and thickest ice is more mobile and is vanishing twice as fast as ice in the rest of the Arctic.
As the Earth warms up, the Arctic Ocean’s year-round ice cover is reducing at an alarming rate. Over the past 35 years, researchers say it’s lost 95 per cent of its mass. However, the core of this ice cover is expected to remain in the years to come… or at least that’s what scientists thought.

A new study took a closer look at the oldest and thickest ice in the region and found that instead of remaining stable as one thought, it is also decreasing. In fact, this area known as the “Last Ice Area” is disappearing twice as fast as the younger, thinner ice of the Arctic Ocean.

The “Last Ice Area” extends 2,000-kilometre (1,240-mile) from the western Canadian Arctic Archipelago to Greenland’s northern coast.

The paper published in the Advancing Earth and Science journal also highlights the importance of the “Last Sea Area” as the final refuge for the region’s wildlife.

To better understand the situation, Eye on the Arctic spoke to lead study author Kent Moore, a physics professor with the University of Toronto Mississauga:

You reviewed satellite images of the Arctic region over 35 years and more precisely the Last Sea Area, what did you find?

There’s not much known about it. Most people would have said: “The ice is very thick, it’s moving very slowly, not much is actually happening in that region.” And to our surprise we found out that wasn’t the case. 

The ice in that area is really quite dynamic. For instance, from year to year, the ice can fluctuate by about a meter in thickness so, some years, it can be four meters thick, some years it’s five meters thick, some years it’s three meters thick. So it’s quite dynamic. And we don’t really understand the reason for that kind of dynamic nature of the ice but it is a region which in fact is actually quite active. The ice is moving as in most of the Arctic, but it is also moving faster in this region.

This visualization shows the age of the Arctic sea ice between 1984 and 2019. Younger sea ice, or first-year ice, is shown in a dark shade of blue while the ice that is four years old or older is shown as white. A graph displayed in the upper left corner quantifies the area covered by sea ice four or more years old in millions of square kilometers. (NASA)

Most people think that the Last Ice Area is a uniform region, but your research has shown that this is not the case, right?

There appear to be two different kinds of subregions. So there is a region in the eastern part which is north of Greenland and then there’s a region sort of north-west of the Arctic archipelago. And the ice motion in these two regions actually is is very uncorrelated. What’s happening in one region isn’t actually happening in the other regions so there was also this sort of notion that ice is moving differently in different parts of this region.

So when we looked at, for instance, the thinning rate. It turns out the ice in the Last Ice Area in both regions is thinning at a rate about twice the whole Arctic. So we’re losing ice in this region at an accelerated rate compared to the rest of the Arctic, which is an interesting result. We don’t understand why that is.

We probably think it’s because the ice is becoming more mobile and so it’s just leaving the region. We don’t think it’s actually melting in situ but we still have to go back.

One of the objectives of your study was also to understand how the Last Ice Area changes throughout the year in order to help determine the most suitable places to provide refuge for wildlife species that depend on sea ice. Could you tell us more about that.

That’s the idea. The Canadian government has proposed the establishment of one refuge up north of Ellesmere Island [Canada’s northernmost region]. Now, we actually have some data that we could use to essentially inform these decisions and maybe suggest that there might be another region which would be more appropriate. You know, where the ice would persist longer, it’s not quite as mobile and so there’s the potential that it will persist for longer. So that’s really our hope that we can actually influence these policy decisions down the road.

If you think about animals, polar bears, seals etc. who really require sea ice to survive, then this notion of this Last Ice Area becomes quite important because it’ll become the refuge for these animals who will be able to survive in this region. And hopefully, over time, as we are able to control our burning of fossil fuels we’ll eventually be able to start reducing CO2 and we’ll eventually start to cool the planet back down. And then this refuge will be the area that will be used to repopulate the rest of the Arctic with these species.

Annual mean sea ice thickness (m) over the Arctic Ocean from 1979 – 2018. The black line surrounds the area where the ice thickness exceeds 3 m and can be considered as the region known as the Last Ice Area. The white lines surround the two areas where the ice thickness exceeds 4m.
(Kent Moore/University of Toronto).

Do you think there is a way to reverse global warming and prevent ice from disappearing?

There are all kinds of proposals of ways to sort of mitigate the warming. Most of them involve putting more clouds. They reflect radiation back to space. So we can put more clouds up in the atmosphere to reduce some of the warming that’s going on. I think all these processes are potentially interesting but the scale is just enormous. 

The Arctic is 10 million square kilometers. We’re not in a position to be able to make clouds in the Arctic that could cover the whole Arctic and actually cool the place down. So a lot of these geoengineering ways to get around climate change, I think are interesting but the scale is just enormous. 

I think what’s more promising is carbon capture technology. There are ways to essentially extract carbon dioxide from the atmosphere. Again they don’t scale but over time people will figure out how to do this on a large enough scale that we can potentially draw down carbon out of the atmosphere. And if we do that then we will in fact reduce the warming effect because if we reduce the CO2 gas in the atmosphere we reduce the greenhouse effect and so the planet will actually cool down. 

But again, we’re not there and we won’t be there for 20 or 30 years. And so that’s why this Last Ice Area becomes quite important because the ice in that region will persist through the middle part of this century. It’ll be an area where these animals can survive.

Mathiew Leiser

Mathiew Leiser, Eye on the Arctic

Né dans le sud de la France d'une mère anglaise et d'un père français, Mathiew Leiser a parcouru le monde dès son plus jeune âge. Après des études de journalisme international à Londres, il a rapidement acquis différentes compétences journalistiques en travaillant comme journaliste indépendant dans divers médias. De la BBC à l'Agence France Presse en passant par l'agence d'UGC Newsflare, Mathiew a acquis de l'expérience dans différents domaines du journalisme. En 2019, il décide de s'installer à Montréal pour affronter les hivers rigoureux et profiter des beaux étés mais surtout développer son journalisme. Il a rapidement intégré Radio Canada International où il s'efforce de donner le meilleur de lui-même au sein des différentes équipes.

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