Climate models had previously underestimated their contribution to future sea level rise.
Ice caps, the melting of which would raise the oceans by several meters, could well collapse with an additional half a degree of global warming. This is shown by current studies that shed light on their hitherto undreamt-of weaknesses.
The Greenland and Antarctic ice caps have lost more than 500 billion tons per year, or six Olympic swimming pools per second, since 2000. But climate models had previously underestimated their contribution to future sea-level rise, considering only the effect of rising air temperatures on the ice and neglecting the interaction complexes between the atmosphere, oceans, ice caps and certain glaciers.
Up to a height of 1.4 m
Researchers from South Korea and the United States have determined how high sea-level rise will be by 2050 according to the various scenarios developed by experts at the Intergovernmental Panel on Climate Change (IPCC). If current climate policies continue, melting in Antarctica and Greenland would cause sea levels to rise by about half a meter. This number would increase to 1.4 meters in the worst case if greenhouse gas emissions from human activities and the use of fossil fuels (such as oil, gas and coal) increased significantly.
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The study by these scientists, published Feb. 14 in the journal Nature Communication, also indicates when runaway melting and runaway disintegration of these ice sheets could occur. “Our model has thresholds between 1.5°C and 2°C warming — 1.8°C is our best estimate — for accelerating ice loss and sea level rise,” said Fabian Schloesser of the University of Hawaii, Co- author of learn. Since the pre-industrial era, global temperatures have already risen by almost 1.2°C (+1.7°C for France).
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Scientists have long known that the West Antarctic and Greenland ice sheets, which could raise sea levels by 13 meters in the long term, have “tipping points.” Beyond these thresholds, their dissolution would be inevitable. However, the temperatures associated with this phenomenon had never been accurately identified.