Scientists are becoming concerned that the Thwaites Glacier in Antarctica, considered the “most important” and “riskiest” glacier in the world and sometimes known as the “doomsday” glacier, may be melting at a faster rate, due to water at the base of the ice that is above the freezing point.
The glacier is the size of Britain or the U.S. state of Florida, contains enough water to raise see levels by half a metre, and “already accounts for 4% of world sea level rise each year—a huge figure for a single glacier,” the BBC reports. Different studies “have forecast its total collapse in a century and also in a few decades,” the New York Times adds. And “the presence of warm water in the grounding line,” where the glacier begins to spread out from bedrock to form ice shelves on the sea, “may support estimates at the faster range.”
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While glaciologists have long been concerned that the Thwaites is melting from below, this is the first time they’ve found warm water at the grounding line.
That matters “because the Thwaites, along with the Pine Island Glacier and a number of smaller glaciers, acts as a brake on part of the much larger West Antarctic Ice Sheet,” the Times explains. “Together, the two bigger glaciers are currently holding back ice that, if melted, would raise the world’s oceans by more than a metre, or about four feet, over centuries, an amount that would put many coastal cities underwater.”
“Warm waters in this part of the world, as remote as they may seem, should serve as a warning to all of us about the potential dire changes to the planet brought about by climate change,” said David Holland, lead researcher with the five-year, US$50-million International Thwaites Glacier Collaboration, and director of New York University’s Environmental Fluid Dynamics Laboratory.
“It certainly has a big impact on our U.S. coast and in many areas,” agreed researcher Twila Moon of the National Snow and Ice Data Center at the University of Colorado Boulder, who isn’t involved with the expedition. Moon added that human action is the biggest predictor of “how much ice we will lose and how quickly we will lose it”.
In a detailed post on the expedition, the BBC explains why scientists are only now conducting the first large-scale survey of the Thwaites. Chief environment correspondent Justin Rowlatt points to the weeks it takes researchers to get to their field camps, 1,000 miles from the latest Antarctic research station, in “the stormiest part of the world’s stormiest continent”.
However, “understanding what is happening here is essential for scientists to be able to predict future sea level rise accurately,” Rowlatt writes. Antarctica holds 90% of the world’s fresh water, and while 80% of that is in the more stable eastern part of the continent, Western Antarctica “is smaller but still huge, and is much more vulnerable to change. Unlike the east it doesn’t rest on high ground. In fact, virtually the whole bed is way below sea level. If it weren’t for the ice, it would be deep ocean with a few islands.”