2023-09-27 04:48:00
At its greatest extent this year, the sea ice It covered less than 17 million square kilometers of Antarctica, an area that is 1 million square kilometers smaller than the previous record low set in 1986, according to preliminary figures released Monday by the National Snow and Ice Data Center (NSIDC). for its acronym in English) from the University of Colorado Boulder. The figure represents the smallest maximum extent in nearly 45 years of satellite records.
Maximum Antarctic ice coverage during the region’s winter, which is the Northern Hemisphere summer, likely occurred on September 10. On that date, sea ice extended over 16.96 million square kilometers, after which it began to shrink, according to the NSIDC. This occurred almost two weeks before the average date of September 23 between 1981 and 2010.
“There is some concern that this could be the beginning of a Long-term trend of declining Antarctic sea ice as oceans warm globallyand the mixing of warm water in the polar layer of the Southern Ocean could continue,” the NSIDC said in a statement.
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Although the causes of sea ice loss in Antarctica are complicated and less known than in the Arctic, scientists believe that the climate change influences, and that the continued decline of ice could exacerbate the effects of warming, since less ice means less sunlight is reflected back into space. Scientists studying Antarctica observed months ago that the ice was struggling to grow back from its February nadir, in a marked departure from usual patterns.
“The last three or four months are like nothing we’ve seen before, or expected, ever,” said Cecilia Bitz, a sea ice climatologist at the University of Washington. “This tells me that the climate change we are seeing is outside our range of experience and cannot be explained by natural variability.”
If drastically lower sea ice coverage than usual continues, more of the coast will be exposed to ocean waves, the effects of which are still unclear, the NSIDC said. Scientists have all kinds of ideas about how sea ice and oceans interact in Antarctica, but most are theoretical and more studies are needed, Bitz said.
arctic summer
In Antarctica, sea ice usually covers the largest area of ocean sometime in September. A slow thaw then begins during the southern hemisphere summer, with the most open waters typically seen in early March. The process is the same in the Arctic, although the winter and summer months are reversed.
The research center also released the latest estimates of summer sea ice coverage on the opposite side of the planet. According to them, sea ice covered only 4.23 million square kilometers of the Arctic Ocean at its lowest point this summer. It is the sixth lowest figure on record, and the 17 lowest were all recorded in the last 17 years.
Scientists are interested in understanding why there may be more or less sea ice in a given year, even though the multi-decade trend is clearly downward, said Flavio Lehner, associate professor of Earth and Atmospheric Sciences at the University of Cornell, who is also chief climate scientist for Polar Bears International.
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“Was it because the air temperature was warmer, because certain weather patterns brought in more warm air?” he asked. “Was it the ocean that transported more warm water to the Arctic? Was it a large storm that broke up the sea ice and facilitated its departure from the Arctic and its melting? “Each year of minimal sea ice has different stories that help us better understand the vulnerability of the ice.”
These variations can have a significant impact on those who live in the region, from indigenous communities to terrestrial and marine animals, to smaller flora and fauna. In the case of polar bears, for example, an earlier freeze in one area could mean an earlier hunting season, while a longer ice season could encourage the migration of bears from other areas. Understanding variation and how animals respond is key to conservation success, Lehner says.
“If we designate something, a national park or a marine sanctuary, but climate change makes it no longer habitable for a species that we’re trying to protect, then that’s a problem,” he said. “It’s about extracting everything we can from the data to be prepared.”
Translated by Paulina Munita.
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