Scientists have just discovered a huge river hidden under Antarctica: ScienceAlert

Scientists have to consider all sorts of variables when it comes to predicting ice loss in Antarctica as the world warms.

Now researchers have to take into account a huge river that runs some 460 kilometers (286 miles) deep under the ice; a longer distance than the River Thames which runs through London in the UK.

Experts say the newly discovered waterway and its offshoots have the potential to dramatically affect how the glacial ice above flows and melts.

The researchers behind the discovery used a combination of airborne radar surveys that can observe through the ice, as well as water flow modelling. The large area examined includes ice from the East and West Antarctic Ice Sheets, with water flowing into the Weddell Sea.

“The region where this study is based contains enough ice to raise global sea levels by 4.3 meters. [14 feet]”says glaciologist Martin Siegert of Imperial College London in the UK.

“How much of this ice melts, and how fast, is related to the slipperiness of the ice base. The recently discovered river system could strongly influence this process.”

Scientists have known for a long time that water flows under the ice caps. This happens in two ways: geothermal heat and friction can melt the ice sheets beneath the glacier, while deep crevices called mills can channel surface meltwater to its base. The latter tends to occur much more in the Arctic and Greenland, where there is more seasonal variation in ice thickness.

What the new study shows is that in Antarctica, there is enough melting at the base of the ice sheets for rivers to form. These high-pressure freshwater channels can in turn accelerate the process of ice melting as the base of the glacier becomes less stable, at the point where it meets the sea.

Ice melting in Greenland occurs via mills (left). Different processes are observed in Antarctica, where subglacial water flows for hundreds of kilometers (right). (Dow et al., nature geoscience 2022)

As we get better at measuring how much ice is melting at the North and South Poles, the processes behind this melting are complicated. Discoveries like the one made here allow us to better understand the underlying processes, meaning that more accurate models of future ice loss can be generated.

“Previous studies have looked at the interaction between the edges of ice sheets and ocean water to determine what melting looks like,” says glaciologist Neil Ross from Newcastle University in the UK.

“However, the discovery of a river that reaches hundreds of kilometers inland, driving some of these processes, shows that we cannot fully understand ice melt without considering the whole system: ice sheet , ocean and fresh water.”

Researchers say that if rates of melting in Antarctica continue to rise and summers are hot enough to create surface melting and mills, it could have a significant impact on the hidden rivers that already exist – potentially making the ice cap here more seasonal, as it is. the case of Greenland.

All of these factors can lead to feedback loops where the additional melting itself creates even faster rates of ice loss. One of the things that could happen is through deep water flows that cause the ice to move faster on land, creating more friction and even more melting.

Now the team wants to use techniques deployed here in other parts of the continent to see what else scientists might not know, with possible ripple effects around 100 kilometers (62 miles) to either side. major rivers flowing under the ice.

“When we first discovered lakes under the ice of Antarctica a few decades ago, we thought they were isolated from each other,” says Siegert.

“Now we are beginning to understand that there are whole systems out there, interconnected by vast river networks, just as they might be if there weren’t thousands of meters of ice above. ‘them.”

The research has been published in nature geoscience.

Leave a Reply

Your email address will not be published. Required fields are marked *