Experts debate global impacts of processes on cold continent
Antarctica has lost a massive body of sea ice the size of Argentina — and scientists are struggling to figure out why. As the Northern Hemisphere succumbs to record-breaking summer heat, much further south, in the dead of winter, another horrendous climate record is being broken: Antarctic sea ice has fallen to an all-time low for this time of year.
Each year, Antarctic sea ice shrinks to its lowest level by the end of February, during the continent's summer. The sea ice then accumulates again during the winter. But this year, scientists have observed something different, says CNN. Sea ice levels have not come close to what was expected. In fact, this is the lowest level for this time of year since records began 45 years ago. According to the National Snow and Ice Data Center (NSIDC), ice coverage is about 1.6 million square kilometers below the previous winter record low set in 2022.
In mid-July, sea ice extent in Antarctica was 2.6 million square kilometers below the average from 1981 to 2010. This area is almost as big as Argentina, or the territories of Texas, California, New Mexico, Arizona, Nevada, Utah and Colorado put together
This phenomenon has been described by some scientists as exceptionally out of the ordinary — something so rare that it likely only happens once every million years, CNN notes.
But Ted Scambos, a glaciologist at the University of Colorado at Boulder, says talking in those terms may not be all that helpful. «The game has changed,» he told CNN. “It makes no sense to talk about the likelihood that this will happen the way it was before, it clearly tells us that the system has changed.”
Scientists are now struggling to figure out why. Antarctica is a remote, complex continent. Unlike the Arctic, where sea ice is constantly shrinking as the climate crisis accelerates, Antarctic sea ice has gone from record high to record low over the past few decades, making it difficult for scientists to understand how it is responding to global warming.
But since 2016, scientists have begun to observe a sharp downward trend. While natural climate variability affects sea ice, many scientists say climate change may be the main cause of ice loss.
“The Antarctic system has always been highly volatile,” notes Ned Scambos. “However, this current level of variation is so high that something drastic has happened in the last two years, but especially this year compared to all previous years.”
Several factors are contributing to sea ice loss, Scambos said. , including the strength of westerly winds around Antarctica, which have been linked to increased pollution of the planet as a result of heating.
“Higher ocean temperatures north of the Antarctic Ocean boundary, mixing with water that is usually somewhat isolated from the rest of the world's oceans, are also part of this idea of how to explain this,” says the scientist.
B At the end of February this year, Antarctic sea ice reached its lowest level since records began at 691,000 square miles, CNN notes.
According to Ned Scambos, this winter's unprecedented occurrence may be indicative of long-term changes in the isolated continent: “It is more likely than not that we will not see the Antarctic system recover from, say, 15 years ago, for a future, perhaps never.»
Other scientists are more cautious. a researcher at the National Snow and Ice Data Center, adding, «It's too early to tell if this is the new normal or not.»
Sea ice plays a vital role. Although it does not directly affect sea level rise, since it is already in the ocean, it has an indirect effect. Its disappearance leaves coastal ice sheets and glaciers open to waves and warm ocean waters, making them more vulnerable to melting and breaking away. A lack of sea ice could also have a significant impact on its wildlife, including krill, which feed on many of the region's whales, and penguins and seals, which rely on sea ice for feeding and rest, CNN notes.
< p>More broadly, Antarctica's sea ice helps regulate the planet's temperature, meaning that its disappearance could have cascading effects far beyond the continent.
Sea ice reflects incoming solar energy back into space, and when it melts, darker ocean waters are being exposed and absorbing solar energy.
Worrisome changes have been observed in parts of Antarctica for some time, continues CNN. The Antarctic Peninsula, a thin chain of ice mountains jutting out from the western side of the continent, is one of the fastest warming places in the Southern Hemisphere.
Last year, scientists said that West Antarctica's huge Thwaites Glacier, also known as “ The Doomsday Glacier is “holding on by a thread” as the planet heats up. Researchers, CNN reports, have calculated that global sea level rise could increase by about 10 feet if Thwaites collapses completely, destroying coastal communities around the world.