Antarctica is melting, and it is happening at a much faster rate than previous scientists.
According to a study published in Nature on Wednesday, losses in the ice sheets of Antarctica, that 60 to 90 percent of the Earth's fresh water, The New York Times & # 39; Kendra Pierre-Louis notes-have tripled since 2007.
The study presents the most comprehensive analysis of Antarctic ice loss to date, based on 24 surveys conducted by 84 scientists from 44 institutions. These researchers estimate that a decade ago, Antarctica lost ice at a rate of 73 billion metric tons per year. Now that number is up to 219 billion tons of ice lost per year, an amazing rate that scientists say could raise sea levels by six inches by 2100.
To put these figures in perspective, the lead author Andrew Shepherd, a professor at the University of Leeds of Earth Observation, tells Pierre-Louis that Brooklyn is currently flooded once a year. Adding six inches to sea level would raise that figure to 20 times a year.
Since 1992, Antarctica has lost more than 3.3 trillion tons of ice, causing an increase of about a quarter of an inch in global sea levels. Shepherd tells Merrit Kennedy of NPR that Antarctica's contributions to sea level rise took a vertiginous leap around 2010. Previous estimates indicated that melting ice in Antarctica contributed to an elevation annual seven-thousandths of an inch, while the last numbers are closer to two hundredths of an inch (0.6 millimeters) per year.
The central concern of researchers is West Antarctica, which experienced an annual loss of 159 billion tons of ice between 2012 and 2017, up to 65 billion tons between 2002 and 2007 . Chris Mooney of the Washington Post reports that the warm water of the underlying oceans has made the glaciers of the region unstable.
Pine Island and Thwaites, two of the largest glaciers in Western Antarctica, have the unpleasant distinction of having the world's highest annual levels of glacier loss. Thwaites is particularly worrisome: it currently acts as a barrier preventing the ocean from reaching West Antarctica, but further ice loss could allow warmer waters to melt the ice sheet in a whole new body of water.
Meanwhile, East Antarctica The ice sheet has experienced both gains and losses in mass. Although the region represents two thirds of Antarctica, Pierre-Louis writes that its fluctuations are not sufficient to compensate for the losses observed in West Antarctica.
A separate study also published in Nature speculates on the consequences of the rapid loss of ice and other indicators of climate change. The document, co-written by nine winners of the Tinker-Muse Prize for Science and Politics in Antarctica, describes two scenarios observed by an observer that dates back to 2070.
Both scenarios are speculative, not decisive, forecasts. In one version, global warming has continued unchecked, leaving Antarctica and the Southern Ocean with a dramatic loss of ice shelves and an accompanying acceleration in global sea levels. In the second, human actions have reduced greenhouse gas emissions and human pressure on the environment, allowing Antarctica to look like the first years of the century: intact ice shelves.
In a statement, lead author Steve Rintoul, from the Southern Oceans Research Center of the Southern Hemisphere and Cooperative Climate Research Center and Antarctic Ecosystems in Hobart, Australia, says: "The trajectory that will be developed in the next 50 years depends on the decisions that are made today … The future of Antarctica is linked to the rest of the planet and human society, now you can take measures that will slow down the rate of environmental change, increase the resilience of Antarctica and reduce the risk that we commit ourselves to irreversible changes of broad impact ".
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