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The fate of the Arctic sea ice

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A shard of open water sits in the foreground of this photo of the outskirts of what scientists call the last ice zone. The American icebreaker Healy looms on the horizon. A new scientific study projects the fate of the Arctic sea ice. Image via Robert Newton / Lamont-Doherty Earth Observatory / Columbia University.

The fate of the Arctic sea ice

In our warming world, the extent of summer sea ice in the Arctic is shrinking. This is less than half of what it was in the 1980s. And the rapid decline of the Arctic sea ice is underway. Will any of us living today live to see an ice-free Arctic in the summer? Scientists at Columbia University in New York City said this month (October 12, 2021) that their new projections point to an intimidating future for the Arctic sea ice.

The new work suggests that an area called the last ice zone – north of Greenland and the Canadian Archipelago, where the ice is normally thickest – is faltering. Optimistic scenarios show that at best, the ice will thin considerably by the end of this century. And pessimistic scenarios show that summer sea ice in the Arctic will disappear by 2100, along with animals, such as seals and polar bears, that depend on it.

The peer-reviewed journal The future of the earth published the study of these scientists on September 2.

Columbia University co-author Robert Newton used the word “experience” to describe Earth’s climate – and the impact of global warming – in the Arctic:

Unfortunately, it is a massive experiment that we are having. If year-round ice disappears, entire ice-dependent ecosystems will collapse and something new will begin.

The last ice zone

The scientists’ study covered an area of ​​1 million square kilometers (about 400,000 square miles) north of Greenland and the coasts of the Canadian archipelago. Previous researchers had called this refuge the area of ​​the last ice because traditionally the ice was the thickest in this region. This is the part of the Arctic that scientists consider to be the last stand of summer ice.

When the North Pole moves away from the sun and the Northern Hemisphere returns to winter, the Arctic Ocean typically freezes after its mild summers. Scientists expect winter ice to continue to form for some time.

The ice in the last ice zone can be up to a meter thick each winter. Summer brings open water to some areas, which helps winds and currents carry floating ice. Most of the ice that coils in the last ice zone comes from the continental shelves off Siberia via transpolar drift, a major current in the Arctic Ocean. Inflows of ice have built ridges up to 10 meters high, which can last 10 years or more, in the last area of ​​ice.

Schematic map of the Arctic with areas divided by red and black lines.
The red outline indicates the last area of ​​ice in the Arctic Ocean. This region is located north of Greenland and the Canadian Arctic Archipelago. The purple section is the Tuvaijuittuq Marine Protected Area of ​​Canada. The black lines indicate the exclusive economic zones of the arctic nations. Image via Newton et al./ The future of the earth/ Columbia University.

A rich marine ecosystem

Multi-year ice in the last ice zone creates a rich marine ecosystem. Algae flourish in thick mats on the edges and bottom of the pack ice. It is the base of the region’s food chain. Tiny animals live in the algae mats. These animals feed the fish. The fish feed the seals. Seals feed polar bears.

Beyond food sources, thick, fuzzy ice provides haunts for seals and caves for polar bears to raise their young. The difficult glacial landscape also makes it difficult for humans to encroach on animal territory.

Sun setting on the horizon of a vast ice field.
Sea ice north of the Canadian Arctic Archipelago. Scientists took this photo from an icebreaker just outside the last area of ​​projected ice, which is nearly impossible to navigate by boat. Image via Robert Newton / Lamont-Doherty Earth Observatory / Columbia University.

Less ice to go around

As the world warms, the ice that forms is thinner and melts faster. There will be less ice in the Arctic Ocean in general, and therefore less ice to drift over the sea and collect in the last area of ​​ice. As the scientists have said:

This will starve the last area of ​​ice for the next several decades. Some ice will continue to drift from the central Arctic and some will form locally, but none will be sufficient to maintain current conditions.

In the optimistic scenario where we achieve lower emissions overall, scientists believe that summer ice in the last ice area will remain, but only one meter thick. This will still allow some arctic animals to survive. In the worst case scenario, with still high emissions, by 2100 there will be no summer ice anywhere in the Arctic Ocean. Newton described what the new environment may involve:

This does not mean that it will be a sterile and lifeless environment. New things will appear, but it may take some time for new creatures to invade.

A stumbling block for southernmost life to take hold in the north is that plants that rely on photosynthesis will always face long, dark months above the Arctic Circle.

In search of the positive

Scientists have said that if we can manage to reduce emissions in the 21st century, the region may be able to hold on to life until temperatures start to drop again. A positive step in the last ice zone is that in 2019 Canada established the Tuvaijuittuq Marine Protected Area of ​​125,000 square miles (320,000 square km). The protected area covers a third of the last ice area and is located in the Inuit territory of Nunavut.

The protections include a ban on mining, transportation and other developments. These protections are only in place for five years, while Canada is considering permanent protection.

White snow dunes under a blue sky and white clouds.
Multi-year ice in the Tuvaijuittuq Marine Protected Area in 2018. Image via Government of Canada / Pierre Coupel.

Pressure on arctic zones

As the ice melts in the Arctic, access opens up to areas that were previously difficult to dig, drill and ship. More marine protected areas will be needed to save the last ice patch from the increased pressure and potential pollution associated with these activities. Scientists argue that:

Now is the time for local communities, Arctic nations and the international community to develop governance and institutional structures conducive to the sustainable management of glacial basins.

Bottom Line: Our warming world means the fate of the Arctic sea ice could be in jeopardy, along with the plants, animals and the rich ecosystem that call it home.

Source: Define the “ice bank” of the last ice zone in the Arctic Ocean and its future evolution

Via Columbia University


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