"Doomsday Glacier" set to retreat "further and faster," scientists warn
The outlook for "Doomsday Glacier" just got gloomier.
Scientists are warning the Antarctic Ice Sheet, known formally as the Thwaites Glacier, will deteriorate "further and faster" and that sea level rise triggered by the melting could impact "hundreds of millions" in coastal communities.
"Towards the end of this century, or into the next century, it is very probable that we will see a rapid increase in the amount of ice coming off of Antarctica," said Dr. Ted Scambos, a glaciologist at the University of Colorado. "The Thwaites is pretty much doomed."
The findings are the culmination of six years of research conducted by the International Thwaites Glacier Collaboration, a collective of more than 100 scientists.
The "Doomsday Glacier," roughly the size of the state of Florida, is one of the largest glaciers in the world. Scientists predict that its collapse could contribute to 65 centimeters, or roughly 26 inches in sea levels to rise.
The sea level rise could be even higher though if you account for the ice the Thwaites will draw in from the large surrounding glacial basins when it collapses. "That total will be closer to three meters of sea level rise," Scambos said.
According to the researchers, the volume of water flowing into the sea from the Thwaites and its neighboring glaciers has doubled from the 1990s to the 2010s.
Approximately 1/3 of the front of the Twaites is currently covered by a thick plate of ice — an ice shelf — floating in the ocean that blocks ice from flowing into the sea. However, Scambos said the melting is accelerating and that the ice sheet is "very near to the point of breakup."
"Probably within the next two or three years, it will break apart into some large icebergs," he said. This will eventually leave the front of the glacier exposed. This may not necessarily lead to a sudden acceleration in melting, but it will change how the ocean interacts with the front of the ice shelf, Scambos said.
Deep ridges that prevent ice from flowing into the ocean are on their way out. The ridges, in the bedrock below the ice sheet in Antarctica, provide a "resistive force" against the ice, Scambos said, that slows down its flow into the ocean. As the Thwaites collapses, it will lose contact with these protective ridges, causing more ice to empty into the ocean.
One of the more surprising findings to come from the International Thwaites Glacier Collaboration was how tidal activity around the glacier is pumping warmer sea water into the ice sheet at high speed. That water, which is a couple of degrees above freezing, is getting trapped in parts of the glacier and forced further upstream.
"It goes in every day, it gets squashed up under the glacier. It completely melts whatever freshwater ice it can, and then it gets ejected, and then the whole thing starts again," said Scambos.
The new findings from the International Thwaites Glacier Collaboration add to a vast body of research on how the deterioration of glaciers worldwide could contribute to sea level rise. In May, a study found that high-pressure ocean water is seeping beneath the "Doomsday Glacier" leading to a "vigorous ice melt."
Study co-author Christine Dow called the Thwaites the "most unstable place in the Antarctic" and said the speed at which its melting could prove "devastating for coastal communities around the world."
Researchers at the University of California, Irvine predicted the ocean could rise by about 60 centimeters, or about 23.6 inches, roughly on par with the predictions from scientists part of the International Thwaites Glacier Collaboration.
Scientists also have also warned about the potential consequences if the Greenland ice sheet were to melt. Greenland's melting ice mass is now the No. 1 driver of sea level rise, according to Paul Bierman, a scientist at the University of Vermont. If it melts completely, scientists project it could lead to 20 to 25 feet of sea-level rise.
Rising global temperatures linked to climate change have made oceans warmed and generated new wind patterns that make these glaciers more susceptible to melting.
"It is very likely related to increasing greenhouse gasses in the atmosphere, which changed wind patterns around Antarctica, and therefore changed ocean circulation around Antarctica," said Scambos. "That's the main culprit."
Scientists project that without intervention, the Thwaites could completely disappear by the 23rd century.
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