The melting sea ice is advancing at such a rate that without a significant reduction in greenhouse gases, the Arctic marine ecosystem could disappear.
Climate change threatens many species, so much so that the human activities causing this upheaval are at the origin of a sixth mass extinction, in progress. The stake is, in large part, that of the habitat: as the environment becomes hostile, biodiversity can no longer live there, and for lack of sufficient time to adapt, the species becomes threatened.
Polar bears are among the most endangered animals. Because their habitat is melting – literally. The same goes for seals.
This is what a study published in September 2021 reminds us. in Earth’s Future, that the research team comments in an article published on October 12, 2021 on the Columbia Climate School website. ” If the usual year-round pack ice disappears, entire ice-dependent ecosystems will collapse, and something new will begin. »
No more bears and seals in 2100 in case of high emissions
The scientists behind this new study focused their research on a specific region of one million square kilometers, but not just any: it is in this area, located in the north of Greenland and on the coasts. of the Canadian archipelago, that the pack ice is the thickest and most resistant. She is also nicknamed The Last Ice Area, because most climate projections show that this is the last place that will resist. Except that it may also melt, in fine, because it is already starting to be achieved in the long term.
To understand the problem, you have to understand how ice forms. Every winter the Arctic Ocean freezes, and although the Earth’s climate continues to warmer, this is expected to last a minimum. The pack ice can then be several meters thick. In summer, the arctic ice melts. A transpolar drift then occurs: the remaining ice is then transported by currents and winds from off Siberia to Greenland and the coasts of Canada. By force, the ice accumulates there, which forms a thick layer, at the origin of the Last Ice Area.
It is on this dynamic, as perfectly regulated as a watch, that the major part of the marine ecosystem of these areas is based. But global warming is generating ever finer ice, which, in addition, is melting more. As a result, in summer, the melt is increased and the Last Ice Area is affected, affected both by the melt and less nourished by the transpolar drift because there is less to transport.
This disturbance has an impact on the marine ecosystem. In a scenario where greenhouse gas emissions remain high, therefore in their current dynamics, then the projection of this study shows that the last islands of ice floes available in summer will have disappeared by 2100. In this scenario, there is no There will be no more sea ice at all during the summer season. The disappearance of the summer sea ice means the disappearance of dependent ecosystems, and therefore the extinction of polar bears and seals, deprived for too long of any habitat. ” This does not mean that it will be a sterile and lifeless environment. New things will emerge, but it may take some time for new creatures to inhabit the places. »
The good news, however, is that a scenario with low greenhouse gas emissions would preserve the ecosystem. Some of the animal populations concerned will not survive, but others will. And the researchers behind this study believe that this scenario is highly probable. Sufficient reduction in greenhouse gases will allow the ice to persist, which may be sufficient to preserve the ecosystem.
The team of authors also calls for the protection of endangered areas of the Last Ice Area, in order, precisely, to conserve at least what is necessary. This is already the case for the Inuit territory of Nunavut, whose surface area of 320,000 km² has been under protection since 2019 and for 5 years, which Canada intends to extend. But the authors point out that many other areas must be protected, especially since the Arctic Ocean is home to oil reserves and mineral deposits (nickel, copper, etc.). The more the ice melts in the summer, the greater the industrial pressure on the region. This industry is precisely contributing to the melting of the ice. Protecting the region also means breaking the vicious circle.