A cavity two thirds the size of Manhattan has formed under one of the world’s most dangerous glaciers. Veuer’s Sam Berman has the full story.
The Thwaites Glacier is one of the most dangerous glaciers in the world, and scientists are eager to travel to Antarctica to study it.
NASA researchers released a study in January that said a giant cavity roughly two-thirds the size of Manhattan was rapidly melting underneath the glacier due to climate change. The cavity is big enough to have contained 14 billion tons of ice, with most of it melting over the last three years.
Even before this cavity, Thwaites’ rapid ice loss and potential impact on global sea levels were significant enough that researchers from around the world planned to physically travel there starting this year.
Only 28 people have ever set foot on the glacier, according to Britain’s Natural Environmental Research Council, or NERC.
So what might happen if Thwaites does collapse?
“It could potentially destabilize the whole region of West Antarctica,” Lucas Zoet, a University of Wisconsin geoscientist, , told USA TODAY.
Thwaites is a ‘wildcard’ for sea levels
The glacier sits in West Antarctica and flows into the Amundsen Sea. Roughly the size of Florida, Thwaites’ melting is currently responsible for about four percent of global sea level rise, according to NASA in its recent study on the glacier’s giant hole.
“It’s a major throughway of how ice gets discharged from West Antarctica into the ocean,” said Zoet.
Thwaites has been difficult to study because it’s far from U.S. bases in the Antarctic and also because the weather is “particularly bad,” said Zoet.
The glacier measures more than 70,000 square miles, making it one of the largest glaciers in the world, said NERC.
The glacier’s grounding line, the point at which ice meets the land underneath, has retreated over 9 miles between 1992 and 2011, according to NERC. As ice and warmer seawater flow underneath the glacier, it lifts off the land and speeds up its retreat.
“If this cavity grows or sort of expands, that’s one way it can get off this last sort of ridge that Thwaites Glacier is hanging on to,” Zoet told USA TODAY.
What especially worries scientists is if the melting accelerates. If all the ice on Thwaites is lost, it would raise ocean levels another two feet, according to the NASA study. But the glacier also backstops neighboring glaciers. If those glaciers also melt, sea levels could rise an additional eight feet, researchers warn.
“It holds a kind of wildcard for being able to increase the rate of sea-level rise quite rapidly if things unfold a certain way,” said Ted Scambos, a senior research scientist with the National Snow and Ice Data Center.
How do you visit a location so remote?
Scambos said research into Thwaites’ retreat started as early as the 1990s, as satellite data got better at tracking Antarctic ice sheets.
Scambos is part of the International Thwaites Glacier Collaboration (ITGC), a partnership between British and American scientists that studies the glacier’s retreat up close.
“Satellites show the Thwaites region is changing rapidly, but to answer the key questions of how much, and how quickly sea-level will change in the future, requires scientists on the ground with sophisticated equipment collecting the data we need to measure rates of ice-volume or ice-mass change,” said William E. Easterling, assistant director for the National Science Foundation’s Directorate for Geosciences, in a statement last year.
“The point is not so much is whether or not it’s going to happen, unless we really change how much heat-trapping gasses we’re putting in the atmosphere,” said Scambos of the glacier’s melting. “Eventually, we’re going to lose big areas of the Antarctic, big areas in Greenland. The important thing is how fast is this going to happen.”
Melting from Greenland and Antarctica would not only bump up sea levels but might bring more extreme weather and dramatic shifts in temperature, according to a study published in Nature in February.
Scambos said coastal cities in the U.S. and worldwide are looking ahead to how higher sea levels could impact them. If Thwaites’ melting happens over centuries, then nations would have more time to get ready.
A faster rise in sea level, however, could force countries to act more urgently.
If that pace were to double or triple suddenly because glacier melt really picked up, “then that’s going to really throw a wrench into the ability for these nations to plan and prepare for the impacts of sea level rise,” Scambos said.
Follow Brett Molina on Twitter: @brettmolina23.
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