Bob Berwyn writes:

Antarctica’s vast ice fields and the floating sea ice surrounding the continent are Earth’s biggest heat shields, bouncing solar radiation away from the planet, but two studies released today show how global warming is encroaching even on the sunlight reflector in the coldest region on the planet.

Research by scientists with the British Antarctic Survey focused on last year’s dizzying sea ice decline. During the austral winter of 2023, Antarctic sea ice extent was about 770,000 square miles below average, an area bigger than Alaska.

Lead author Rachel Diamond said the modeling study showed that such an extreme decline would be a one-in-2,000-years event without climate change, “which tells us that the event was very extreme,” she said. “Anything less than one-in-100 is considered exceptionally unlikely.”

In a separate paper, another team of scientists documented how strong tides push seawater surprisingly far beneath the tongue of the Thwaites Glacier in West Antarctica, reinforcing concerns about the glacier’s melt speeding up and adding to sea level rise.

“Pressurized seawater intrusions will induce vigorous melt of grounded ice over kilometers, making the glacier more vulnerable to ocean warming, and increasing the projections of ice mass loss,” the authors wrote in the paper, published in the Proceedings of the National Academy of Sciences.

“The worry is that we are underestimating the speed that the glacier is changing, which would be devastating for coastal communities around the world,” said coauthor Christine Dow, professor in the Faculty of Environment at the University of Waterloo in Ontario, Canada. [Continue reading…]