The Surprise Discovery of Antarctica’s Massive Meltwater Network, and the Increasing Instability of its Largest Ice Shelf

The results of two new studies regarding Antarctic glaciers have been released, and the results of each shocked the researchers conducting them, including the first on-site survey of the Totten Ice Shelf, and the first large-scale survey of the Antarctic continent as a whole. Additionally, the results of the two studies do not paint an optimistic picture for the stability of our southern continent’s glaciers.

The continent-wide survey employed a combination of aerial photography and satellite imagery, with some of the images dating back to 1947, to discover that during the Antarctic summer, the continent has a vast network of approximately 700 open water rivers and streams flowing over the ice, including in areas that scientists assumed were too cold for liquid water to flow. The individual bodies of water pooling on the ice were also extremely large, with some lakes being 80 kilometers (50 miles) long, with some streams exhibiting as much water flow as the Hudson River.

The researchers say that this network is not new, and has apparently existed for decades, although they are unable to determine if the volume of water is growing or not, in response to increasing temperatures around the globe. This free-flowing water may also be a mixed blessing: On one hand, researchers studying the Nansen Ice Shelf feel that the streams might be helping to stabilize that region, carrying the otherwise warmer water away from the ice. But Columbia University’s Robin Bell warns "It could develop this way in other places, or things could just devolve into giant slush puddles. Ice is dynamic and complex, and we don’t have the data yet."

Meanwhile, the survey of the Totten Ice Shelf has confirmed fears that warm ocean water under the shelf is eroding away the ice from below. "This could explain why Totten has been thinning in the past few decades," explains oceanographer Stephen Rintoul, from the University of Tasmania. Rintoul’s team was finally able to reach the Totten Ice Shelf after their icebreaker, RSV Aurora Australis, was able to find a path through the dense ice to the remote region in 2015, making them the first expedition to make it to the remote region.

Found in East Antarctica, the Totten glacier is Antarctica’s largest, and was previously thought to be stable. Aerial and satellite surveys of the region conducted in recent years have shown otherwise, indicating that the ice sheet is shrinking. "Almost everything we thought we knew about East Antarctica has turned out to be wrong”, explains Australian Antarctic Division glaciologist Tas van Ommen. While the retreat of the ice at Totten is slow, the volume of ice where the glacier meets the sea acts as a plug that keeps the rest of the glacier from sliding into the ocean. It is feared that if the continental ice starts to slide northward into the ocean, it will be lubricated by sub-glacial lakes that lie in a layer between the ice and the underlying continent.

The new discoveries that are being made are fueling a new push to gather as much information about Antarctica’s glaciers as possible, as little is actually known about how the continent’s ice might react to increasing extremes caused by climate change. "Once glaciers retreat beyond a certain point, things may go downhill very quickly and cause rapid sea level rise," warns Eric Rignot, a glaciologist at the University of California, Irvine. "We don’t want to sleepwalk into a calamity like this."