Mountain glaciers are perhaps the most evident symbol of global warming. Just jump on our Alps, where the snowy peaks leave more and more often the place to the gray of the rocks: in 60 years it is estimated that the Italian glaciers, among the most affected in Europe, have reduced by 30 percent. However, it is not better even in the rest of the world. A study recently published on Nature by the researchers of the Glambie project (Glacier Mass Balance Intercomparison Exercise) of ASA has calculated that in the last 20 years the land has lost 5 percent of the volume of its mountain glaciers, with tips that reach 39 percent in the areas most affected by climate change, such as central Europe.
The study represents the most updated scientific effort made to date to verify the state of the mountain glaciers of the planet, or all the continental percentage snow formations with the exception of the two largest: that of Greenland in the north hemisphere, and the Antarctic one in the south. Although individually these local glaciers are small in size, taken together they represent one of the main reserves of fresh water from the earth, for a total volume that was in 2000 estimated by 700 thousand square kilometers, or 121 thousand billion tons of water, sufficient to raise the level of the oceans by more than 300 meters if they are completely dissolved.
The research has combined direct measurements of the ice status, where available, with the information obtained using satellites for the observation of the earth. By obtaining a precise image of what happened in the last 20 years to the mountain glaciers of our planet: on average, we said it, 5 percent of their total volume has disappeared, with strong variations at regional level, ranging from the 2 percent lost by the Antarctic and Subantartici glaciers, up to 39 percent disappeared instead of our latitudes.
In total, the amount of ice that has dissolved in the last 20 years is 6,500 billion tons. And he contributed to an increase of 18 millimeters of the Mari level, more than they have done so far the dissolution of the ice of Greenland and Antarctica. The loss of perennial ice on our mountains has also reduced the availability of fresh water in many areas of the planet. “To put things in perspective – explains Michael Zemp, researcher of the University of Zurich who contributed to the study – the 273 billion tons of ice that melts every year are equivalent to the quantity of water that consumes the entire human population in 30 years, assuming that about three liters per head are used every day”.
The situation emerged from the research is already in itself not very reassuring. But in the future things are destined to become worse: the models speak of a further reduction of mountain glaciers that oscillates between 25 percent (low emissions scenario, less and less plausible) and 50 percent (high emissions scenario) by 2100.
“Our most recent observations and modeling studies indicate that the mass loss of glaciers will continue, and could also accelerate, over the next century – concludes the glaciologist Samuel Nussbaumer, Project Manager of the Glammbie project – this supports the request for concrete and urgent actions to reduce the greenhouse gas emissions and the relative heating advanced by the IPCC, in order to limit in order to limit. The impact of glaciers in terms of local geological dangers, availability of fresh water and raising the level of the seas “.