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Antarctic glaciers could quickly disintegrate in centuries rather than millennia, according to a new study. This allows the sea level to rise a few meters, while we are now talking about one meter in 300 years.
Posted August 27, 2020 at 7:00 am
“We’ve used artificial intelligence to model the spread of hydro fracturing in Antarctica over the next few decades,” said Yao Lai, a glaciologist at Columbia University, who is the lead author of the study published Wednesday in the journal. Nature Communications. “This is a phenomenon we often see in Greenland, lakes that form on the surface of glaciers and cause destabilizing cracks. ”
Currently, hydraulic fracturing affects “much less than 1%” of the surface of Antarctic glaciers. “The temperature is very low, so there’s little surface melt,” said Jeremy Bassis, a University of Michigan climatologist who commented on the research in the same issue of Nature Communications. “But that could change in the coming decades. ”
The model of crack propagation in glaciers has been known since the 1970s. “But you couldn’t use it to see long-term evolution in Antarctica, because you have to start with what you’re seeing now. , from satellite data, says Bassis. The area is too large and the cracks are too rare for a human eye to analyze. My colleagues at Columbia made it possible with artificial intelligence. ”
120 meters: Minimum level, compared to now, of sea level during the last ice age, 20,000 years ago. (Source: IPCC)
In Ms. Lai’s study, the worst-case scenario that could see Antarctica’s glaciers covered with 60% water is the most pessimistic of the IPCC, the UN group that makes climate forecasting. This is a world where the world’s population does not peak in the 21st century, where poor countries remain poor, where advances in electric vehicles and solar power stop, and where coal is making a strong comeback as a fuel. .
“Until recently, few experts thought that Antarctica could lose a significant portion of its glaciers within a few centuries, but it is a dire scenario that more and more people are considering,” Bassis said. But several studies, including this one, show it could happen before the year 2500, perhaps as early as the 21st century. ”
Glaciers in East Antarctica are currently gaining ice, but the much smaller ones in West Antarctica are losing nearly 100 billion tons per year, contributing to a 1cm rise in sea levels. between 1970 and 2010, according to the IPCC.
Since the pre-industrial era, sea levels have risen by about 20 cm. The IPCC estimates that this could reach 1 m by 2300, perhaps as early as 2100 in the most pessimistic scenario. If all of Antarctica’s glaciers melted, sea level rise would be 53 meters (7.5 meters for those in Greenland).
Could we see a sea level rise of 10 meters before 2200? “No, I don’t think it could go a few yards in the worst case,” said Mr. Bassis.