A recent study published in Science Glacier models used to better understand the effect that each degree of global warming will have in the worldwide melting of glaciers. The impacts of heating that the earth has already experienced have not yet been fully carried out, because the glaciers have not reached balance with the changing climate. The models provide information about how much ice is ready to lose the world and how much more can be stored by limiting our emissions and heating.
“Eight models of evolution of different glaciers were used to simulate the evolution of glaciers under a total of 80 heating scenarios,” Harry Zekololi told Glacierhub in an interview. Zekollari is the main author of the study and associate professor of glaciology at the Brussell Vrije Universiteit in Belgium. “This was a community effort made within the framework of the glacier model intercomparity (Glaciermip3). There was a protocol to follow for anyone who wanted to join and perform the experiments, and was open to all. We could use the information of all models to make global estimates, ”he said.
The heating scenarios were based on the assumption that the temperature would reach a maximum level and then stop heating. If temperatures reach that peak today, glaciers will continue melted in the coming years, independently. This is because glaciers take some time to respond to changing climatic conditions.
“The glaciers are so unbalanced with current warming, in general, it takes them some time to catch up ‘and reach a new balance or stable state,” he said Mike KaplanGeologist of the Lamont-Doherty Earth Observatory, which is part of the Columbia Climate School. Study how glaciers, climates and landscapes have changed in the past. “Even if we stopped the human impacts in the weather this same minute, we must consider that things not only adjust immediately.”
“See a bit like an ice cube that you get from a freezer,” Zekololi explained. “It will not melt immediately, but it will take a long time. The same applies to the glaciers, but on a longer spatial and temporary scale.”
The planet has already reached 1.2 degrees Celsius warming above preindustrial levels. According to the study, at this temperature, we are locked up to lose 40 percent of glacial ice on Earth. No matter the mitigation efforts made, this ice is as good as missing. But the remaining ice still has potential to be saved. Reach a maximum temperature before, at a lower temperature, later in a higher one, could preserve a significant amount of glacial ice.
“In the long term, for each tenth of degree less global warming that can be limited between 3.0 degrees Celsius and 1.5 degrees Celsius, you can preserve 2 percent of the mass of the additional glacier,” said Lilian Schuster, who worked in the study as part of his dissertation research in the Department of Atmospheric and Criospheric Research at the University of the University of the University of Innsbruck in Innsbruck in Innsbruck Austria, and then became a postdocal investigation. For this ice to save, humans must drastically change the current trajectory.
“With current policies, we head to a heating of approximately 2.7 degrees Celsius above preindustrial levels, which, in the long term, would lead to a loss of three quarters of the global glacier mass,” Zekollari said. “If we are able to limit heating to 1.5 degrees Celsius, in line with the Paris Agreement, then only half of that glacier mass would be lost.”
The glaciers are very sensitive to each small temperature change. Kaplan described them as: “The proverbial canary in the coal mine. They are a direct physical manifestation of atmospheric conditions and will always be very sensitive to heating.”
These findings indicate that there are several different levels of loss of glaciers that the earth can experience, depending on how much heating can be limited. Although these differences are significant, in all scenarios human populations will feel the impacts of a world with melted ice.
“The vast majority of lost ice will eventually reach the oceans, thus contributing to the increase in sea level. Sea levels are currently increasing approximately 4 mm/year, of which approximately 1 mm/year comes from melting glaciers,” Zekollari said. The remaining increase in sea level comes from the fusion of the ice layer (2 mm/year) and thermal expansion (1 mm/year).
“There are many more reasons to worry about the loss of glaciers: changes in the water supply affect ecosystems and are important for mountain communities, since they have a spiritual and tourist value,” Zekollari continued. Mountain communities also depend on streams fed by the melting of glacier for irrigation and domestic supplies. Although a heating climate that melts glaciers can provide more short -term water, in the long term, these communities will face the risk of greater water shortage. Through glaciers modeling in studies like this, the global world may be more prepared for lasting repercussions of climate change.
“The situation is gloomy, but there is still hope, and we can save a substantial part of our glaciers if we can limit heating,” Zekololi said.
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