Bloomberg – At its greatest extent this year, sea ice covered less than 17 million square kilometers of Antarctica, an area 1 million square kilometers smaller than the previous record low set in 1986, according to preliminary figures released Monday by National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder. The figure represents the smallest maximum extent in nearly 45 years of satellite records.
Antarctica’s maximum ice cover during the region’s winter, the Northern Hemisphere’s summer, probably occurred on September 10. At that point, according to the NSIDC, the sea ice covered an area of 16.96 million square kilometers and began shrinking thereafter. This happened almost two weeks before the average date of September 23rd between 1981 and 2010.
“There is concern that this could be the start of a long-term trend of Antarctic sea ice decline as global oceans warm and mixing of warm water in the Southern Ocean polar ice cap may continue,” statement.
Although the causes of sea ice loss in Antarctica are complicated and less understood than in the Arctic, scientists believe climate change plays a role. and that the continued decline of ice could increase 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 low point, a significant departure from usual patterns.
“The last three or four months are like nothing we’ve ever seen or expected before,” 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 realm of experience and cannot be explained by natural variability.”
If sea ice coverage remains significantly lower than usual, more of the coast will be exposed to ocean waves. The impact is still unclear, the NSIDC noted. Scientists have all sorts of ideas about how sea ice and oceans interact in Antarctica, but most are theoretical and more study is needed, Bitz said.
arctic summer
In Antarctica, sea ice typically covers the largest area of ocean sometime in September. A slow thaw then begins during the Southern Hemisphere summer, with most open water typically seen in early March. In the Arctic the process is the same, but the winter and summer months are swapped.
The research center also released the latest estimates of summer sea ice cover on the other side of the planet. Accordingly, sea ice covered only 4.23 million square kilometers of the Arctic Ocean at its deepest point this summer. This is the sixth lowest level on record, and the 17 lowest levels have all occurred in the last 17 years.
Scientists are interested in understanding why there may be more or less sea ice in a given year, even if the trend is clearly declining over several decades, said Flavio Lehner, an associate professor of earth and atmospheric sciences at the University of Cornell, who also Chief climate scientist for Polar Bears International is involved.
“Was it because the air temperature was warmer because certain weather conditions 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 differences can have significant impacts on people in the region, from indigenous communities to land and marine animals to smaller flora and fauna. In the case of polar bears, for example, an earlier frost in one area could mean an earlier hunting season, while a longer ice season could encourage the migration of bears from other areas. Understanding the variation and response of animals is the key to success in conservation, says Lehner.
“If we designate something, a national park or a marine reserve, but climate change makes it no longer habitable for a species that we want to protect.”, then it’s a problem,” he said. “It’s about getting everything possible out of the data to be processed.”
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