Antarctica is Missing an Argentina-Sized Amount of Sea Ice This Year
Published on July 31, 2023 at 03:54AM
The world just broke "another terrifying climate record," reports CNN: Antarctic sea ice has fallen to unprecedented lows for this time of year. Every year, Antarctic sea ice shrinks to its lowest levels towards the end of February, during the continent's summer. The sea ice then builds back up over the winter. But this year scientists have observed something different. The sea ice has not returned to anywhere near expected levels. In fact it is at the lowest levels for this time of year since records began 45 years ago. The ice is around 1.6 million square kilometers (0.6 million square miles) below the previous winter record low set in 2022, according to data from the National Snow and Ice Data Center (NSIDC). In mid-July, Antarctica's sea ice was 2.6 million square kilometers (1 million square miles) below the 1981 to 2010 average. That is an area nearly as large as Argentina or the combined areas of Texas, California, New Mexico, Arizona, Nevada, Utah, and Colorado. The phenomenon has been described by some scientists as off-the-charts exceptional — something that is so rare, the odds are that it only happens once in millions of years. But Ted Scambos, a glaciologist at the University of Colorado Boulder, said that speaking in these terms may not be that helpful. "The game has changed," he told CNN. "There's no sense talking about the odds of it happening the way the system used to be, it's clearly telling us that the system has changed...." This winter's unprecedented occurrence may indicate a long-term change for the isolated continent, Scambos said. "It is more likely than not that we won't see the Antarctic system recover the way it did, say, 15 years ago, for a very long period into the future, and possibly 'ever.'" Others are more cautious. "It's a large departure from average but we know that Antarctic sea ice exhibits large year to year variability," Julienne Stroeve, a senior scientist at the National Snow and Ice Data Center told CNN, adding "it's too early to say if this is the new normal or not." The glaciologist describes the change as "so extreme that something radical has changed in the past two years, but especially this year, relative to all previous years going back at least 45 years." And CNN adds that meanwhile in the Arctic, "sea ice has been on a consistently downwards trajectory as the climate crisis accelerates." Other possible consequences of the missing sea ice: Sea ice reflects sunlight back into space, CNN notes, so when it melts, it "exposes the darker ocean waters beneath which absorb the sun's energy." Sea ice floats on the water, so its loss doesn't directly affect rising sea levels, CNN points out. But the disappearance of sea ice does leave coastal ice sheets and glaciers "exposed to waves and warm ocean waters, making them more vulnerable to melting and breaking off." In February NASA reported that global sea levels "are rising as a result of human-caused global warming, with recent rates being unprecedented over the past 2,500-plus years." Seawater expands when it warms, but NASA also blames the added water from melting ice sheets and glaciers, resulting in a 3.89-inch rise since 1993, and 7.97 inches (200 mm) since 1900.
Published on July 31, 2023 at 03:54AM
The world just broke "another terrifying climate record," reports CNN: Antarctic sea ice has fallen to unprecedented lows for this time of year. Every year, Antarctic sea ice shrinks to its lowest levels towards the end of February, during the continent's summer. The sea ice then builds back up over the winter. But this year scientists have observed something different. The sea ice has not returned to anywhere near expected levels. In fact it is at the lowest levels for this time of year since records began 45 years ago. The ice is around 1.6 million square kilometers (0.6 million square miles) below the previous winter record low set in 2022, according to data from the National Snow and Ice Data Center (NSIDC). In mid-July, Antarctica's sea ice was 2.6 million square kilometers (1 million square miles) below the 1981 to 2010 average. That is an area nearly as large as Argentina or the combined areas of Texas, California, New Mexico, Arizona, Nevada, Utah, and Colorado. The phenomenon has been described by some scientists as off-the-charts exceptional — something that is so rare, the odds are that it only happens once in millions of years. But Ted Scambos, a glaciologist at the University of Colorado Boulder, said that speaking in these terms may not be that helpful. "The game has changed," he told CNN. "There's no sense talking about the odds of it happening the way the system used to be, it's clearly telling us that the system has changed...." This winter's unprecedented occurrence may indicate a long-term change for the isolated continent, Scambos said. "It is more likely than not that we won't see the Antarctic system recover the way it did, say, 15 years ago, for a very long period into the future, and possibly 'ever.'" Others are more cautious. "It's a large departure from average but we know that Antarctic sea ice exhibits large year to year variability," Julienne Stroeve, a senior scientist at the National Snow and Ice Data Center told CNN, adding "it's too early to say if this is the new normal or not." The glaciologist describes the change as "so extreme that something radical has changed in the past two years, but especially this year, relative to all previous years going back at least 45 years." And CNN adds that meanwhile in the Arctic, "sea ice has been on a consistently downwards trajectory as the climate crisis accelerates." Other possible consequences of the missing sea ice: Sea ice reflects sunlight back into space, CNN notes, so when it melts, it "exposes the darker ocean waters beneath which absorb the sun's energy." Sea ice floats on the water, so its loss doesn't directly affect rising sea levels, CNN points out. But the disappearance of sea ice does leave coastal ice sheets and glaciers "exposed to waves and warm ocean waters, making them more vulnerable to melting and breaking off." In February NASA reported that global sea levels "are rising as a result of human-caused global warming, with recent rates being unprecedented over the past 2,500-plus years." Seawater expands when it warms, but NASA also blames the added water from melting ice sheets and glaciers, resulting in a 3.89-inch rise since 1993, and 7.97 inches (200 mm) since 1900.
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