Scientists Just Found Another Vulnerability in Antarctica's Icy Armor

This is how warm water can undercut one of the biggest glaciers in East Antarctica. Image: Greene et al., 2017

It’s becoming increasingly clear that no place on Earth is safe from the influence of carbon pollution, and East Antarctica is no exception. Research published on Wednesday in Science Advances is the latest troubling sign to emerge for the region, showing that natural processes that cause melt could accelerate due to climate change. It’s just going to happen in a way you might not expect.

The findings focus on Totten Glacier, which links to a basin roughly the size of Spain covered in 2.5 miles of ice. If all that ice melted, it would be enough to raise sea levels up to 11.5 feet.


East Antarctica was supposed to be a safe place for ice. High in elevation, cold and windy for most of the year, its vast trove of land ice seemed impervious to the influences of climate change.

“We thought it was a sleeping giant,” Chad Greene, an ice sheet researcher at the University of Texas who led the new research, told Earther. “Now we see it’s moving around a little.”

That movement comes courtesy of winds over the ocean, which kick up stronger than normal every few years.

When that happens, they churn the water on the surface. Because it’s fed by ice melt, that water tends to be fresher than the salty water below, allowing it to float despite being colder.


But the churn provides an opening for the warm (relatively speaking) water below to rise and take its place. Currents eventually steer the balmy 36°F water under the ice shelf, which is a floating chunk of ice that extends out from the glacier.

Greene likened it to a swimmer doing a lap in a pool of oil and vinegar.

“The surface oil will spread apart and the layer beneath will rise up to the top,” he explained. “The winds cause the surface water to diverge and that has an effect of pulling the warm waters up to the continental shelf.”


Now 36°F sounds damn cold because it is. But it’s about 3°F warmer than the water that usually floats on the surface and immediately underneath the ice shelf. The seemingly small change in water temperature has a huge impact on how fast the ice flows into the sea, a change that Greene and his co-authors use to approximate melt. Specifically, models suggest that the 3°F increase in water temperature causes the ice shelf to melt up to 10 times faster.

All this happens roughly 19 months after the initial winds and ocean mixing. This whole chain of events is totally natural, and the findings give scientists an unprecedented opportunity to start predicting seasonal changes to the ice shelf.


But that’s not where the story ends. Climate change adds a more a sinister note about what could await Totten Glacier.


As the planet warms, winds off the coast of East Antarctica are expected to become more fierce. That means more repeated bouts of hot water undercutting the ice shelf that could turn this gentle natural process into a blow torch repeatedly pointed at the ice.

“Wind is projected to intensify over the Southern Ocean so this is a way that CO2 could eventually lead to sea level rise without warming up the air and melting the ice from the top and without warming ocean but just moving warm ocean water around,” Greene said.


The research focuses on the Totten Glacier because it shares unfortunate geographical similarities as glaciers in West Antarctica. Most of the glacier sits on bedrock that’s below sea level. That quirk allows warm water to have a far greater impact on the ice than other glaciers that are mostly above sea level.

In West Antarctica, the Pine Island and Thwaites glaciers are both near or already in a state of unstoppable collapse. The story is a bit different from Totten, which is thicker and will thus respond more slowly to any influx of warm water than its West Antarctica counterparts. Greene stressed that it isn’t near the point of no return, but that the findings are important to understand future sea level rise.


In essence, they’re yet another case that shows that the more we learn about the impacts of climate change on ice, the more sea level rise estimates continue to be revised upward.

Managing editor, Earther

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