In Greenland, the melting of the ice sheet is irreparable, according to scientists arguing that it will continue to shrink " even if global warming stops today " because snowfall no longer compensates for the loss of ice.
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" Greenland's glaciers have sort of passed a point of no return, where the snowfall that replenishes the ice sheet each year can no longer counterbalance the ice flowing from the glaciers to the ocean, " explained in a statement from Ohio State University, where the authors of the study published by the journal Communications Earth and Environment work, on Aug. 13.
Climate change is weighing heavily on glaciers and the melting ice cap threatens tens of millions of people around the world. Alarming reports of melting ice across the gigantic Arctic territory, a region that is warming twice as fast as the rest of the planet, have been increasing for several years. This island of two million km2 (nearly four times the area of France) bordered for three quarters by the waters of the Arctic Ocean, is 85% covered by ice.
" The study confirms the results of many other studies (...) according to which the combination of melting and detachment of icebergs explains the large amount of ice lost from Greenland over the past two decades ", summarized for the AFP Ruth Mottram, climatologist from the Danish Meteorological Institute (DMI), specialist in the Arctic.
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In the 1980s and 1990s, the ice sheet was losing about 450 gigatons (about 450 billion tonnes) of ice per year, replaced by snowfall, scientists noted after analyzing some 40 years of data. From the 2000s, the melting accelerated, climbing to 500 gigatons but was not compensated by the snowfall. " The Greenland ice sheet is losing mass at an accelerated rate in the 21st century, making it the most important contributor to sea level rise, " the study said.
The " point of no return " in question
However, while the melting of Greenlandic glaciers linked to climate change is extremely worrying, other members of the scientific community consider it premature to speak of a point of no return. “ We don't know how much greenhouse gas concentrations will increase, ” Ruth Mottram told AFP.
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The results published in Nature show that " even if we stabilized temperatures (and greenhouse gas emissions) at current levels, the ice sheet would continue to melt, but only until its size was again in equilibrium. with the climate, ”she said. According to a recent study by the University of Lincoln (United Kingdom), the melting ice in Greenland is expected to contribute 10 to 12 cm to the rise in sea level by 2100.
The IPCC estimated in 2013 that the sea level would rise by 60 centimeters by the end of the century. In addition, the melting ice cap is not only a symptom of climate change, it is also a factor in global warming. When the ice melts, it is replaced by the ocean which reflects less of the sun's rays and absorbs them, accelerating the thaw.