Will the climate crisis sound the death knell for glaciers? A study, published in Science Thursday, January 5, demonstrates how compromised their future is. Nearly half of the world’s white giants, or 104,000, are expected to disappear by 2100, even if global warming were limited to 1.5°C compared to the pre-industrial era. This objective, the most ambitious of the Paris agreement, is considered out of reach by a growing number of scientists. More than 80% of them would be condemned in the event of a rise in mercury of 4°C, a pessimistic scenario of uncontrolled use of fossil fuels (coal, oil and gas), the main causes of global warming.
This new work, carried out by an international team of scientists, also shows that the world’s 215,000 glaciers – with the exception of the Greenland and Antarctic ice caps – could lose between 26% and 41% of their mass compared to that of 2015, according to the different temperature scenarios. This study worsens previous projections, which notably fueled the latest report of the Intergovernmental Panel on Climate Change (IPCC).
“We have observed a linear relationship between the increase in global temperature and the loss of glacier mass.indicates Etienne Berthier, glaciologist (CNRS) at the Laboratory for Space Geophysics and Oceanography Studies in Toulouse, and one of the authors of the study. Each additional fraction of a degree increases the melting of the ice. »
The little ones first
The majority of glaciers whose death is announced for the end of the century are the smallest, those whose area is less than 1 km2, which actually constitute 80% of the total. Scientists say their disappearance will have only a minor effect on sea level rise, but it could “negatively affect the water cycle, tourism, local cultures and glacier-related hazards”, such as collapses. Glaciers, which play an important role as water towers, help supply water to 1.9 billion people around the world.
If all regions of the planet are affected, the glaciers of low and medium latitudes will prove to be the most affected, particularly in central Europe, the Caucasus, Scandinavia, northern Asia, western Canada and the USA or New Zealand. They should undergo a strong deglaciation from 2°C of warming and almost total at + 3°C.
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