RSE et Développement Durable

Antarctica today takes a lot of heat from above, thanks to two hundred years of carbon-belching human activity and the warming this has caused. An increasing number of researchers also think the frozen Southern Continent faces significant warming from below: Hot rock pluming upward through Earth's mantle, leaking heat through the crust, and melting the bottoms of Antarctic ice sheets.

(...) The effect, first proposed 30 years ago, seems especially strong in West Antarctica, where ice sheet losses are most dramatic and contributing to sea-level rise. But few scientists believed this was happening, at least initially. "I thought it was crazy," Hélène Seroussi, a climatologist and ice researcher at NASA's Jet Propulsion Laboratory, said in a press release. "I didn't see how we could have that amount of heat and still have ice on top of it."

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One line of research has discovered, documented, and even drilled into and explored a vast system of sub-glacial lakes and rivers. This water helps lubricate the movement of ice sheets from the snowy mountains to the sea - and certain parts of the Southern Continent, where there's a lot of sub-glacial water - are moving and melting faster than others.

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Scientists have also dug into the mystery of a bulge in Earth's crust below West Antarctica, called the Marie Byrd Land Dome. At first, it was thought the crust was thicker there. But earthquake-like seismic measurements disproved that idea. Something else is buoying the region, and recent seismic imaging - essentially 3D-radar for Earth's crust and mantle - suggests there's a warm plume of rock below West Antarctica. (Just as sound waves travel slower through liquids than solids, seismic waves slow down when encountering hotter, more gooey, and less-dense rock.) Since this could just be an irregularity in the mantle, Seroussi and her colleagues borrowed from a computer model used to simulate the giant plume of hot rock below Yellowstone National Park.

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"Without a plume-like heating source," they said, "our simulations show that intrinsic heating and crustal sources do not provide enough energy to generate significant amounts of basal meltwater."