Even If We Meet Paris Goals Of 2C , Antarctic Ice Loss Will Raise Sea Levels By 2.5 Meters
Melting of the Antarctic ice sheet will cause sea level rises of about two and a half metres around the world, even if the goals of the Paris agreement are met, research has shown. The melting is likely to take place over a long period, beyond the end of this century, but is almost certain to be irreversible, because of the way in which the ice cap is likely to melt, the new model reveals.
Even if temperatures were to fall again after rising by 2C (3.6F), the temperature limit set out in the Paris agreement, the ice would not regrow to its initial state, because of self-reinforcing mechanisms that destabilise the ice, according to the paper published in the journal Nature.
The more we learn about Antarctica, the direr the predictions become, said Anders Levermann, co-author of the paper from the Potsdam Institute for Climate Impact Research. We get enormous sea level rise [from Antarctic melting] even if we keep to the Paris agreement, and catastrophic amounts if we dont. The Antarctic ice sheet has existed in roughly its current form for about 34m years, but its future form will be decided in our lifetimes, according to Levermann. We will be renowned in future as the people who flooded New York City, he told the Guardian.
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While the Antarctic ice sheet will take centuries to melt in response to temperature rises, the new Nature paper showed how difficult it would be to reverse. Antarcticas vast ice cap, which covers about as much of the earth as North America and is close to three miles (5km) thick, holds more than half of the earths fresh water. Some of it is floating sea ice, which does not cause sea level rises in the way of ice melting from land, and is subject to melting from above and below because of the warming sea. The researchers examined how ice over land in the region can be expected to melt, and found a strong hysteresis effect, which makes it harder for ice to re-form than to melt. When the ice melts, its surface sinks lower down and sits in warmer air, so it requires lower temperatures for the ice to reform than it did to keep the existing ice stable.
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https://www.theguardian.com/environment/2020/sep/23/melting-antarctic-ice-will-raise-sea-level-by-25-metres-even-if-paris-climate-goals-are-met-study-finds