Scientists say the window to protect the world’s largest ice sheet from significant shrinking is shrinking, with troubling new predictions that it has the potential to unleash long-term sea level rises of up to 5 meters if greenhouse gas emissions targets are not met.
Last studypublished in Nature, it combined recent findings on possible vulnerabilities in the bedrock and seafloor topography — particularly in areas where glaciers interact with warm water — with an analysis of warm periods in Earth’s past.
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The team of researchers from Australia, Britain, France and the United States found that if the increase in global temperature is below the upper limit set in the 2015 Paris climate agreement – two degrees Celsius above pre-industrial levels – that means the ice sheet is increasing less than half. meters (1.6 ft) to sea level by the year 2500. Any rise above this temperature has the potential to increase sea level by as much as5 meters (16.4 ft) in the same period.
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“The choices we make today in terms of emissions reductions will be determined by whether East Antarctica will remain largely dormant as a very large ice sheet, or whether we will begin to make some unstoppable changes that will contribute to the impact of climate change,” Nereli Abram, a university climate scientist, co-author of Australian Nationality and Study, said in an interview: “The problem of sea level rise that we are already dealing with.”
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UN Secretary-General Antonio Guterres warned earlier this year that the most ambitious goal enshrined in the Paris Agreement — to limit global temperature rise to 1.5°C (2.7°F) above pre-industrial levels – On life support.
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Evidence from seafloor sediments around East Antarctica suggests that part of the ice sheet collapsed and contributed to sea-level rise by several meters during the mid-Pliocene, about 3 million years ago, when temperatures were about 2 to 4 million years higher, the report said. researchers. degrees Celsius. from now on. Nearly 400,000 years ago, there is evidence that part of the ice sheet retreated more than 400 miles inland, at a time when temperatures were more than 2 degrees Celsius higher than they are today.
“The most important lesson from the past is that the East Antarctic Ice Sheet is very sensitive to even relatively modest warming scenarios. It’s not as stable and protected as we once thought,” Abram said.
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Chris Stokes, a professor of geography at Britain’s University of Durham and lead author of the study, said satellite observations indicate the ice sheet is shrinking and retreating, especially when glaciers come into contact with warm ocean currents.
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This ice sheet is the largest in the world and contains the equivalent of 52 meters [171 feet] from sea level and it is very important that we do not wake this sleeping giant.”
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Nick Guledge, a glaciologist at the Antarctic Research Center in Wellington, New Zealand, who was not involved in the study, said the real concern for East Antarctica is the period beyond what the research paper considers. Even if greenhouse gas emissions decrease or stop, the amount of trapped heat will decline for millennia as the ocean continues to absorb heat from the atmosphere.
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“The recent warm periods mentioned in the paper help with these conclusions, but the uncertainties remain very large,” he said.
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Australian scientists will embark on a campaign in the coming years to deepen their understanding of the Denham Glacier, a 12-mile-wide glacier that flows over the deepest undersea valley in the East Antarctic Ice Sheet. Scientists already have warned That the valley could provide a potential path for the ocean to infiltrate deep into the center of Antarctica.
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“We understand the moon better than East Antarctica. Matt King, co-author of the latest study and one of the experts said: expert Sea level change and ice sheet change at the University of Tasmania.
