Antarctica just hit record low sea ice

There are concerns that this could be the start of a long-term downward trend in Antarctic sea ice as oceans globally warm and mixing of warm water in the Southern Ocean polar layer may continue, according to an NSIDC announcement on Monday.

Sea ice around the polar regions grows and melts with the seasons. In Antarctica, sea ice usually reaches its minimum extent at the end of the Southern Hemisphere summer around February. It reaches its maximum range in late winter in mid to late September. In February of this year, scientists reported that floating Antarctic sea ice reached an all-time low at the end of the summer, and sea ice growth remained slow throughout the winter.

This year, Antarctica reached its annual maximum coverage on September 10, about 13 days earlier than average. At the time, annual ice cover was at a record low of 6.55 million square miles, down 398,000 square miles from the previous record low set in 1986.

That’s surprisingly low, NSIDC glaciologist Twila Moon said. We have this extremely low minimum and during the Antarctic autumn and Antarctic winter there has been no recovery towards previous higher ranges. You began to see its effect throughout the year.

Sea ice around the polar regions plays an important role in protecting the adjacent ice sheets. Less sea ice means less sunlight is reflected back into space, causing the waters to warm more and the surrounding ice and glaciers to be destabilized. Coastlines are also much more exposed with less sea ice, removing a buffer that can help protect melting ice shelves or ice sheets.

Scientists have long observed the decline of sea ice and its effects in the Arctic. In a separate announcement Monday, the NSIDC said the extent of Arctic sea ice at the end of this summer was the sixth lowest in nearly 45 years of satellite records, extending a troubling trend of the lowest Arctic summer sea ice extent in the past 17 years. ranges recorded.

Declining trends in Antarctic sea ice have been more unclear, but scientists now think the continent is facing a tipping point, like the Arctic. In just seven years, Antarctica has experienced three new record low sea ice summers. The study, published Sept. 13, said the data show that the processes controlling Antarctic sea ice coverage may have changed.

Now we’ve also seen this loss of sea ice, as ice forming on the ocean surface appears to have been affected by ocean warming and possibly other processes, Moon said. We may now be looking at a very different system that affects the Antarctic sea ice every season.

Antarctica has also responded to climate change in other ways, Moon said. Antarctica and the Arctic are warming faster than the global average. Warmer ocean temperatures across the continent have caused major ice melt around the ice sheet, including destabilizing the Thwaites Glacier, which is about the size of Florida and accounts for 4 percent of annual global sea-level rise. Changes in both ocean circulation and the atmosphere have also become more apparent, Moon said.

That’s not great news, said Gail Whiteman, an expert on global risks from polar climate change and professor of sustainability at the University of Exeter. Polar ice is one of the world’s biggest insurance policies against rapid climate change, and in both Arctic and Southern sea ice, we are seeing problems and alarm bells ringing.