By Levon Sevunts
The study, Arctic Sea Ice in CMIP6, published in Geophysical Research Letters analyzed recent results from 40 different climate models.
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Using these models, scientists from 21 research institutes from around the world assessed the evolution of Arctic sea-ice cover in a scenario with high CO2 emissions và little climate protection.
As expected, summer Arctic sea-ice disappeared quickly in these simulations.
However, some of these models also showed that the ice still disappeared even in some simulations where CO2 emissions were rapidly reduced.
“The key point is that we have sầu now reached a point that whether we are very aggressive sầu in cutting our emissions or whether we go business as usual, we will be seeing years without any ice in the Arctic Ocean in the summer,” said study co-author Bruno Tremblay, associate professor in the Department of Atmospheric và Oceanic Sciences at McGill University.
What will change between different scenargame ios is the frequency at which this phenomenon occurs, Tremblay added.
“If we go business as usual, it will be a much more frequent occurrence, it will be pretty much always the case starting in 2030, 2035 or 2040,” Trembleay told Radio Canada International in an interview from Toulouse, France, where he is on sabbatical.
“If we vì severe cuts lớn our CO2 emissions, it will be an occurrence that happens once in a while but it will still occur.”
An ice-free ArcticPhoto: Thomas Nilsen
Each summer, the area of sea-ice coverage decreases & grows again in winter.
However, since researchers began keeping satellite records in 1979, summer Arctic ice has lost 40 per cent of its area và up lớn 70 per cent of its volume.
The entire Arctic Ocean, the smallest & the shallowest of world oceans, covers an area of about 14.06 million square kilometres.
Scientists define an ice-không tính phí Arctic as one in which the Arctic Ocean sea ice covers an area of about 1 million square kilometres or less, Tremblay said.
“When you have sầu 1 million square kilometres of ice left, you have a thin, narrow band of ice left in the north of the Canadian Arctic Archipelago & some ice left within the archipelago but basically the entire Arctic Ocean is miễn phí of ice except for that very localized region,” Tremblay said.
The ice-không tính tiền season is also expected to lớn get substantially longer, he added.
“Ice always comes baông chồng in the winter but it will come baông xã later & later, because as you have less và less ice, more solar light is absorbed in the surface ocean, it takes longer in the fall before you ventilate all this heat into lớn the atmosphere,” Tremblay said.
“And so gradually October becomes ice-free as well, August as well, not just September, and then November-December becomes ice-miễn phí & June as well, so the ice-không tính tiền season becomes wider and wider.”
Affecting Arctic ecosystems
This will substantially affect the Arctic ecosystem and climate, particularly ice-dependent species such as polar bears và seals, Tremblay said.
“This will mean for them a longer & longer period without ice, which basically means fasting,” Tremblay said.
“For polar bears it means staying on lvà & they will have lớn wait until the over of October, November and then finally December before they can return và hunt
Female polar bears give sầu birth to cubs in January and February and then go on the ice in May khổng lồ hunt seals & fatten up until the ice-không lấy phí season comes and they have lớn fast, he said.
With the ice-free season coming earlier & lasting longer, this means polar bears will have to lớn fast for much longer.
Retìm kiếm in the Western Hudson Bay in the southern part of the Canadian Arctic shows that the average fasting time for polar bears in the area has gone from 107 days in the 1980s to lớn 130 days in the early 2000s.
As a result, the Western Hudson Bay polar bear population is estimated khổng lồ have dropped by 30 per cent since the 1980s. Other polar bear populations further north in the Canadian Arctic are stable or even growing. However, that could change with the warming climate.
“We’re seeing in the Hudson Bay now is what we will be seeing the Arctic Ocean in a decade or two,” Tremblay said.
The models looking even further into the future into lớn 2100 and 2200 predict an ice không tính phí Arctic even in the winter, Tremblay said.
However, as the Arctic sea-ice extent decreases during this transition khổng lồ an ice-free Arctic, the year-to-year variability in extent is expected to lớn greatly increase, Tremblay said.
The last time the Earth experienced conditions like these was about 6,000 years ago at the over of the last glacial period when the solar insulation was much higher than it is now, Tremblay said.
“And what we’re going khổng lồ see at the end of the century, you’re going khổng lồ have sầu to go back even further bachồng, lượt thích hundreds of thousands of years, millions of years baông xã when you saw conditions that warm,” Tremblay said.
This story is posted on Independent Barents Obhệ thống as part of Eye on the Arctic, a collaborative partnership between public & private circumpolar truyền thông organizations.