Scientists Discover Ominous Waters Under Antarctic Ice

Scientists Discover Ominous Waters Under Antarctic Ice

That’s not a huge amount of cast iron per square foot. But over an area the size of two large European countries, it is getting bigger. “What we concluded is that the melting is really low, it’s like one millimeter per year,” says Siegert. “But the watershed is huge, so you don’t need a lot of cast iron. All this flows into this river, several hundred kilometers long, and whose flow is three times greater than that of the Thames in London.

This water is under extreme pressure, both because there is a lot of ice pressing down from above and because there is not much space between the ice and bedrock for liquid can move. “And because it’s under high pressure, it can act to lift ice off its bed, which can reduce friction,” says Siegert. “And if you reduce that basal friction, the ice can flow much faster than it otherwise would.” Think of this ice like a puck sliding across an air hockey table, only instead of rolling on air, the ice rolls on pressurized water.

According to University of Waterloo glaciologist Christine Dow, lead author of the new paper, this huge hidden river “can pump an enormous volume of fresh water into the ocean.” And that could be bad news for the ice cap’s connection to the floating ice shelf. “The place where the ice starts to float is the most sensitive region,” she continues. “So anything that changes where that ground line sits will have a significant control over the sea level rise that we will have in the future.”

What holds the ice sheet back and keeps sea levels from jumping several feet is the pack ice, which acts like a big heavy plug to slow the flow of a glacier into the sea. But in Antarctica, these corks fragment, as the warming water eats away at their undersides. Antarctica’s Thwaites Glacier ice shelf (aka Doomsday Glacier), for example, could collapse within three to five years, according to recent research. If we lost Thwaites entirely, that alone would contribute to two feet at sea level.

It’s not just Thwaites. Researchers find that many of Antarctica’s ground lines recede, like hairlines. Yet the models that predict the future state of these glaciers assume that the stranding lines are static. Scientists already know that these patterns are missing another key factor that can affect how well these lines hold: an effect known as tidal pumping. As the tides flow in and out, they raise and lower the pack ice, allowing warm seawater to rush inland and melt the underside of the ice. This new research now shows that pressurized meltwater also comes from the other direction, flowing inland towards the ground line.

“The problem is that if you have a lot of fresh water pumped into the ocean, it buoyantly rises to the base of the ice and drags the warm ocean water with it, melting that ice,” says Dow. . “It pushes that grounding line back. And then all the ice that was once stranded now floats towards immediately add to sea level rise and destabilize the whole system. In other words, the ice does not need to melt to raise the water level, because its massive mass also displaces the liquid.

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