Global warming is causing a drastic reduction in summer sea ice in the Arctic. So much that today that strip occupies less than half of what it was in 1980. Scientists have investigated whether ice – and the creatures that need it to survive – will hold out somewhere in the Arctic all year in the future. The results of the study are worrying: only if carbon emissions are reduced will a small strip of ice persist. In the most pessimistic scenario – if emissions continue their current evolution – the summer ice will disappear before 2100. And with it, the seals, the walruses, the polar bears & mldr;
The study reveals that the last arctic region in which the ice will disappear occupies an area of one million square kilometers north of Greenland and the shores of the Canadian archipelago. There, the sea ice is the thickest in the entire Arctic and, therefore, will be the one that most and best resists the rise in temperatures. It will be the last frozen refuge, the one that scientists call the ‘last ice zone‘.
Scientists have studied three possible scenarios. And in all of them by the summer of 2050 the ice in that region “will drastically thin & rdquor ;. In the optimistic scenario, if carbon emissions can be controlled in the next few years, a small patch of summer ice could persist indefinitely. In the pessimistic scenario, in which emissions continue on their current path, the summer ice would disappear by the year 2100, along with the animals it serves as habitat, such as seals and polar bears.
Collapse of all ecosystems
Collapse of all ecosystemsThe research, published in the magazine ‘Earth’s Future’, warns that the disappearance of Arctic ice will cause the collapse of all ecosystems that depend on it. “It will start something new,” and very different from what exists now, said study co-author Robert Newton, a senior research scientist at Columbia University’s Lamont-Doherty Earth Observatory.
Researchers have been pondering the fate of Arctic sea ice for decades. In 2009, several scientists came together to analyze what will happen in the ‘last ice zone’.
On winter, most of the surface of the Arctic Ocean freezes, and will likely continue to do so in the future, even as temperatures continue to rise. Ice can grow up to a meter thick each winter, and if it survives one or more summers, it can reach several meters.
On summer melting is recorded and scattered areas of open water appear. This helps winds and currents carry floating ice over great distances in various turns, including what experts call the ‘Transpolar Drift Stream’, which carries it clockwise from Siberia. towards Greenland and Canada.
Every year, some ice is blown into the North Atlantic between Greenland and Norway. But much of the ice is heading against the northernmost coasts of the Arctic, along Greenland and the Canadian islands. There, repeated flows of ice can form pressure layers and ridges up to ten meters, the researchers explain.
An increasingly thin layer of ice
An increasingly thin layer of iceThe result of all this is a rich marine ecosystem. Along the edges of the Earth and the bottom of multi-year ice, photosynthetic diatoms (microorganisms) flourish and eventually form thick layers.
The microorganisms feed the tiny animals that live in and near the ice. And these in turn feed the fish, which feed the seals, which feed the polar bears & mldr; The thick and irregular topography also provides ample hiding places for seal dens and ice caves for polar bears to overwinter and raise cubs.
Historically, most of the ice that ends up in this area comes from the continental shelves off Siberia through Transpolar drift, but also comes from the central Arctic Ocean.
The problem is that the ocean is now forming an increasingly thin ice sheet, which is melting faster. As this trend progresses, according to the researchers, the ‘last ice zone’ “will starve & rdquor; in the next decades. “Some ice will continue to arrive from the central Arctic and some will form locally, but it will not be enough to maintain current conditions,” they emphasize.
The study concludes that by the middle of this century, even in a low emissions scenario, the central Arctic ice will decrease. And the thick ice of several years will become “a thing of the past”. Under these conditions, locally formed summer ice will persist in the last ice area, but only one meter thick. In all other scenarios the ice will disappear completely.
Good news and bad news
Good news and bad newsThere is good news: in the most optimistic scenario, some seals, bears and other creatures could survive, as they currently do in similar summer conditions throughout western Alaska and parts of Hudson Bay.
But there is also other bad news: under the highest emissions scenario, by 2100, ice will not even form locally. “There will be no more summer ice anywhere, and no ice-dependent ecosystems,” the scientists warn. And there will be no more seals, no bears.
“This is not to say that it will be a barren and lifeless environment,” Newton said. “New things will emerge, but it may take a while for new creatures to occupy that area & rdquor ;.
Fish, diatoms, or other biota can come from the North Atlantic, but it’s unclear if they could survive there year-round. Because, as the researchers point out, “it may be warmer, but the planet’s rotation around the Sun will not change, and any new occupants, including photosynthetic organisms, will have to deal with the long arctic winter without sunlight & rdquor;.
Researchers want to see the bright side. If the world progresses enough and slows down the emission of carbon into the atmosphere during the 21st century, the Arctic region could hold out long enough for temperatures to start to drop again and the ‘last ice zone’ could start to grow from new.
Scientists claim marine protected areas
Scientists claim marine protected areasIf the ‘last ice zone’ is to be preserved, the researchers emphasize, the formation of marine protected areas across the Arctic. Because that ocean and its coasts are home to billions of dollars in oil reserves and mineral deposits like nickel and copper. And as the ice clears and the waters open in summer, the pressure to excavate, drill and open transportation corridors will increase, with the consequent risk of contamination. In fact, the Russian oil company Rosneft already has leases in some areas that have traditionally ‘fed’ the ‘last ice zone’.
“Spilled oil and industrial or agricultural pollutants have been identified as potential hazards”, the researchers collect in the report.
So far, only Canada has mobilized. In 2009 he established the Tuvaijuittuq marine protected area, 320,000 square kilometers, in the Inuit territory of Nunavut. It covers the middle third of the ‘last ice zone’. The area was thus protected against mining, transportation and other developments for five years.. Canada is considering permanent protection for that area.
The remainder of the region lies within the Canadian Northwest Territories, pro-mining, and has so far resisted declaring protection, and off Greenland, which has so far addressed the problem evasively.
Reference study: https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021EF001988
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Main photo: pixabay