2100: Only one third of the world’s glaciers remain | Polarjournal
Glaciers such as Monacobreen on Svalbard will lose more mass by the end of the century than earlier studies predicted. Photo: Julia Hager

The more clearly a goal is defined, the more effectively it can be achieved. Of course, it must be concrete, comprehensible and realistic in order to achieve it. That’s the way companies are successful through their employees. But what about the very concrete, comprehensible and realistic goal of limiting global warming to 1.5°C? Mankind seems to be failing miserably at this. Right now, we’re moving closer to a warming of 2.7°C, which would result in the loss of two-thirds of the world’s glaciers by 2100, according to a new study that appeared in the journal Science.

If this were to happen, not only would sea levels rise by more than eleven centimeters, but the supply of drinking water would no longer be guaranteed for a large part of the world’s population. In addition, the risk of landslides and floods increases due to melting glaciers.

However, it doesn’t have to come to that. According to the same study, we still have the possibility of preserving about half of the glaciers if we manage to limit warming to 1.5°C. This would be technically possible, but unlikely according to many scientists. Small glaciers in particular will disappear in any case.

“No matter what, we’re going to lose a lot of the glaciers,” says David Rounce, a glaciologist and professor of engineering at Carnegie Mellon University in Pennsylvania and lead author of the study. “But we have the ability to make a difference by limiting how many glaciers we lose.”

By 2100, glaciers will be found virtually only in the polar regions, such as here on the Antarctic Peninsula and in the Himalayas. Photo: Julia Hager

The study takes into account all 215,000 land glaciers on Earth, excluding those on the ice sheets in Greenland and Antarctica. Much more comprehensively than in previous studies, the international research team used computer simulations to calculate how many glaciers would disappear under different warming scenarios, how many trillions of tons of ice would melt, and how much the contribution to sea level rise would be.

The marginal areas of Greenland, the Canadian Arctic, and Antarctica and Sub-Antarctica alone account for 60 to 65 percent of the total contribution of glaciers to sea level rise under +2°C warming. Ice mass loss in these regions with large glaciers will continue beyond the end of the century. Especially for the large glaciers, there is a linear relationship between temperature increase and mass loss. This means that every tenth of a degree Celsius has a significant impact on ice loss. In other regions with smaller glaciers, such as the Russian Arctic, Svalbard, and Iceland, however, this relationship is weaker due to more variable temperatures and precipitation.

By the end of the century, apart from glaciers in the Karakoram and Kunlun Mountains, the remaining ice mass will be found mainly in southeast Alaska, the northern Canadian Arctic, the margins of Greenland, Svalbard, the Russian Arctic, and Antarctica and Subantarctica, with a large proportion of these glaciers flowing into the ocean.

Ice loss from the fronts of marine-terminating glaciers will decrease by 2100, according to the study, but only because glaciers as a whole will thin and carry less ice toward the ocean. Photo: Julia Hager

In the latest calculations, the team of authors explicitly included ice loss from the fronts of these marine-terminating glaciers, in contrast to previous studies, and say that accounting for it over the next century will be critical. Their results show that by 2100, ice mass loss from glacier fronts will decrease for the +2°C scenario. They blame their thinning, retreat to the mainland and the resulting reduced ice flow into the ocean.
In Antarctica and Sub-Antarctica, the Russian Arctic, and Svalbard, the relative contribution from melting at the glacier front will be highest.

In a brief article on the study, Gudfinna Adalgeirsdóttir and Timothy D. James conclude by writing that “any effort to limit global mean temperature rise will have a direct effect on reducing how many glaciers will be lost,” even though it is already too late to prevent the loss of many glaciers.

Julia Hager, PolarJournal

Link to the study: David R. Raunze et al. Global glacier change in the 21st century: Every increase in temperature matters. Science, 379 (6627). DOI: https://doi.org/10.1126/science.abo1324

More on the subject:

Print Friendly, PDF & Email
error: Content is protected !!
Share This