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A Network of Lakes Lies Under East Antarctica’s Biggest Glacier

The water underneath the Totten Glacier may force researchers to recalculate how quickly climate change may melt the massive ice sheet

(Nick Morgan/Australian Antarctic Division)
smithsonianmag.com

Researchers armed with trunks full of explosives have learned something new, and concerning, about the Totten Glacier in East Antartica, one of the continent's largest and fastest moving ice masses. Using seismic testing, a team from the Australian Antarctic Program has found that the 1.2-mile-thick glacier sits on top of a network of sub-glacial lakes, a finding that could change calculations about sea-level rise due to climate change.

During 160 days on the ice, scientists drilled seven-foot holes in the ice then set off explosive charges. “These explosions sent out sound waves, which then echoed off different layers in the ice and bedrock,” glaciologist Ben Galton-Fenzi tells Jessica Hayes at the Australian Broadcasting Corporation. “We place geophones along the surface of the glacier to listen to the reflected sound, giving us a picture of what lies beneath the ice.”

Just how fast the glacier inches into the sea is partially a function of what type of material it sits on. “If there’s bedrock under the glacier, it’s sticky and will move more slowly, but if there’s water or soft sediments, the glacier will move faster,” Galton-Fenzi says in a press release.

How quickly the Totten moves toward the sea has huge global implications. While the Intergovernmental Panel on Climate Change's average projection is for the planet’s oceans to rise about a half meter by the end of this century, the calculations didn’t take into consideration the lake district sitting under Totten and could force researchers to update that estimate.

“If I took all the ice contained in the [Totten Glacier] catchment, spread it out over the global oceans, sea levels would go up seven meters [23 feet],” Galton-Fenzi tells Hayes. “We actually know for a fact that the Totten Glacier is one of the regions that's actually changing. We know there's warm water present under the glacier, so we expect this is one of the regions in east Antarctica that's going to change first.”

This is not the only recent study to help researchers understand the massive glacier. Similar seismic testing last year revealed that a larger percentage of the glacier than previously thought is floating on the surface of the ocean instead of sitting on bedrock. That makes the glacier more susceptible to warming oceans and explains some of the ice loss measured on the glacier.

A study from NASA released in December shows that smaller glaciers around Totten have lost significant amounts of ice in the last decade. Four glaciers in Vincennes Bay, west of Totten, have lost 9 feet of elevation since 2008. Glaciers in an area east of Totten called Wilkes Land have doubled their rate of melting since 2009 and are losing about .8 feet of ice per year.

Though those ice losses are relatively modest, it suggests the ice in East Antarctica is beginning to “wake up.” “The change doesn’t seem random; it looks systematic,” says Alex Gardner, a glaciologist with NASA’s Jet Propulsion Laboratory. “And that systematic nature hints at underlying ocean influences that have been incredibly strong in West Antarctica. Now we might be finding clear links of the ocean starting to influence East Antarctica.”

The next step for understanding the potential future of Totten is to drill down all the way to the sub-glacial lakes. But Galton-Fenzi tells Lisa Martin at The Guardian that there may not be funding for that project, which he says needs to be a global priority. “This is the single biggest problem we need to face and have answers to over the next couple of decades,” he says. “I’m not just a scientist saying ‘I need more money’ … I’ve got kids who are six and eight and [climate change] is a real threat for them.”

About Jason Daley

Jason Daley is a Madison, Wisconsin-based writer specializing in natural history, science, travel, and the environment. His work has appeared in Discover, Popular Science, Outside, Men’s Journal, and other magazines.

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