Water scarcity, rising sea levels, changed flora and fauna: the progressive melting of glaciers due to global warming is having some serious effects. Well shows one in the journal Science published studythat even in the best-case scenario, a large part of the glaciers will disappear. According to this, about 49 percent of the approximately 215,000 glaciers considered are likely to melt by 2100 – even if the temperature increase is limited to 1.5 degrees. However, the authors also have a positive message: Immediate measures to protect the climate and every tenth of a degree saved in warming can slow down the process.
According to the study by the international team led by David Rounce from Carnegie Mellon University in Pittsburgh, the melting of the glaciers is linearly related to the average global temperature increase. With an increase of two degrees, the target agreed in the Paris Agreement for maximum warming by the end of the century, almost 70 percent of glaciers with a size of up to one square kilometer could disappear. Almost 20 percent of the glaciers, which are between one and ten square kilometers in size, would melt completely. Glaciers are large masses of snow, firn and ice, which usually flow slowly from mountains towards the valley.
With its calculations, the team confirms previous findings on the extent of glacier melt. “The study took a very detailed look at various processes that could not previously be considered. But it is not the case that something completely new comes out of the study that was not previously known,” says glaciologist Olaf Eisen from the Alfred-Wegener- Institute, the Helmholtz Center for Polar and Marine Research, which was not involved in the investigation.
If the climate targets given at the UN climate conference COP26 in 2021 are met, this would result in a temperature increase of 2.7 degrees by the end of the century. With a warming of about 3 degrees, glaciers would almost completely disappear in many regions, as the study goes on to say. These included those in the European Alps, western Canada, the United States and New Zealand.
“The German glaciers will probably not reach 2050.”
According to Eisen, the German glaciers can no longer be saved: “The issue is over.” The Southern Schneeferner melted away last year, leaving only four glaciers in Germany. “They will meet the same fate,” said Eisen. How fast the melt in Germany progresses depends only on the temperatures in the coming winters. “If we get winters like 2020 or 2021, when it was cold and wet in the spring, they might last another decade, but the German glaciers probably won’t reach 2050.”
According to the study, with an average global temperature increase of four degrees, four out of five glaciers worldwide would disappear by 2100. The ice mass of all glaciers would decrease by 41 percent. That would have dramatic consequences. Because the melting of the glaciers causes the sea level to rise. In the case of a warming of 1.5 degrees, the contribution of the glaciers to the sea level rise would be 90 millimeters, with a warming of 4 degrees it would be more than 150 millimeters. “Every millimeter of sea-level rise leads to more flooding in coastal areas, and glaciers are one of the main drivers of sea-level rise,” said Fabien Maussion of the University of Innsbruck, co-author of the study.
In addition, the glaciers are natural freshwater reservoirs. “When they’re gone, it doesn’t mean that we don’t have water anymore, but that the water doesn’t come when it’s needed – namely in dry, hot summer months,” shared co-author Matthias Huss from ETH Zurich with. When the ice is gone, water shortages are to be expected, especially during periods of drought. “This is a problem for irrigation, drinking water, goods transport, fauna and flora and so on,” says Huss.
Nevertheless, Rounce’s team emphasizes that it is quite possible to slow down the melt in the medium term through immediate and comprehensive climate protection measures on a global scale. “Even if we can’t save the glaciers as they currently look, every tenth of a degree of warming saved results in a smaller decline and thus smaller negative effects,” says Huss.