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Opinion Humanity should not test whether Antarctica’s ice will hold out

An aerial view of a crack forming in Antarctica's Thwaites Glacier in 2019. (Jeremy Harbeck/OIB/NASA)
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The world’s massive ice stores are melting, and researchers are only beginning to evaluate what that means. This is but one of so many signals that climate change will not wait until it is more convenient for humanity to face it; world governments must tackle the problem now.

In Antarctica, a major bulwark against rapid ice disintegration “is likely to shatter into hundreds of icebergs,” according to Oregon State University’s Erin Pettit, who presented this month new satellite images showing that the eastern ice shelf abutting the massive Thwaites Glacier is cracking and could break up within the next few years. Once gone, the enormous mass of glacial ice that the shelf currently holds back will move toward the sea at three times its current rate, threatening a substantial boost in rising sea levels.

Meanwhile, The Post’s Sarah Kaplan reports that, in the Arctic, perilous climate feedbacks threaten to initiate dangerous downward spirals. Rain in typically frigid places such as Greenland can make the surface ice darker — and therefore more prone to absorb solar radiation, causing more melting. Increased wildlife activity in a warmer Arctic, such as beaver dam-building, could disturb the permafrost, with potentially dire consequences; whatever carbon is locked within, in the form of long-frozen organic matter, could thaw and escape, adding potentially huge amounts of greenhouse gases such as methane into the atmosphere.

There is still much uncertainty. A May study projected that increased snowfall over Antarctica, which would accumulate on the continent’s land-based glaciers, might largely compensate for ice lost to the sea. The net result could be only about 1½ inches of sea-level rise from Antarctic ice melting by 2100. But the study also warned that catastrophic melting scenarios are also possible, resulting in perhaps eight inches of sea-level rise. Other recent scientific projections have been more alarming.

Sea level-related disasters over the past decade, such as the massive flooding 2012’s superstorm Sandy inflicted on New York, have been a warning. Sea-level rise and ocean warming are generational threats that will hit the country’s children and grandchildren far harder. As bad as it seems now, glacial melting might really kick in after mid-century — and sea-level rise promises to be even worse after 2100.

Even if the net impact of Antarctic melting is muted, and even if Greenland’s ice remains miraculously sturdy, higher global temperatures will cause the water already in the ocean to expand. Coastal communities and island nations must brace for more water-related destruction. And world leaders must continue trying to restrain global emissions. Humanity should not test whether unrestrained warming will catastrophically reshape the world’s coastlines. As is the case with so many other potential climate consequences, allowing this gamble to play out is not worth the risk.