River Found Under Antarctica Accelerates Ice Loss as Global Temperatures Rise

An unexpected river that was discovered beneath the Antarctic ice sheet has an impact on how the ice flows and melts, possibly accelerating ice loss as global temperatures rise.

A recent study reveals the 460 km river and describes how it gathers water from an area the size of France and Germany put together at the bottom of the Antarctic ice sheet. Its discovery demonstrates that the ice sheet's base has much more active water flow than was previously believed, which may make it more vulnerable to climatic changes.

Researchers from Newcastle University, the University of Waterloo in Canada, Imperial College London, and Universiti Malaysia Terengganu worked on the study.

4.3-Meter Rise

Co-author Professor Martin Siegert, from the Grantham Institute at Imperial College London, said that a few decades ago when lakes were first found beneath the Antarctic ice, people believed the water bodies were separate from one another. They are now beginning to realize that there are entire systems underground that are linked by enormous river networks like they could be if there weren't tens of thousands of meters of ice covering them.

The area where this study was conducted has sufficient ice to raise the water levels worldwide by 4.3 meters. How quickly and how much of this ice melts depends on how slick the ice base is. This process might be significantly influenced by the recently discovered river system.

Water Under the Ice

There are two main ways that water can enter beneath ice sheets: either through melting at the base brought on by friction even as the ice moves over land and the natural heat of the Earth or through surface meltwater flowing downward through deep crevasses.

The ice sheets surrounding the south and north poles, however, differ in some ways. In Greenland, the summer months see intense melting of the surface during which enormous volumes of water channel through deep crevasses known as moulins.

However, because the summers continue to be too cold, there is not enough surface melting to form moulins in Antarctica. This led to the assumption that there was not a lot of water present at the bottom of the Antarctic ice sheets.

The discovery flips this notion on its head by demonstrating that there is enough water from the basal melt alone to develop into vast river systems beneath kilometers of ice.

The discovery was made using a combination of ice sheet hydrology modeling and airborne radar surveys that enable scientists to investigate beneath the ice. The team concentrated on an understudied and largely inaccessible region that contains ice from both the West and East Antarctic ice sheets and flows into the Weddell Sea.

Missing Link

Dr. Christine Dow, the study's lead researcher from the University of Waterloo said that it is a testament to how much more needs to be understood about the continent that such a vast system could remain undiscovered until now.

She said that satellite measurements show how much ice is being lost from Antarctica's regions, but the reason why is still unknown. Dow said that this finding might fill in a gap in their models. They might be drastically underestimating the speed the system will melt if they don't take these river systems into account.

According to NASA, with the help of their ICESat-2, or Ice, Cloud, and Land Elevation Satellite, scientists were able to precisely map the subglacial lakes. The satellite measures the elevation of the ice surface. Despite its colossal thickness, the height changes as lakes beneath the ice sheet fill or empty.

Dow added that Models and forecasts of how the ice will behave in the future under continued global warming and how significantly this could raise sea levels worldwide can only be made by understanding why ice is being lost.

The Whole System

Co-author Dr. Neil Ross, from the University of Newcastle, said that to understand what melting looks like, earlier studies looked into the relationship between ocean water and the edges of ice sheets. To understand what melting looks like, earlier studies looked into the relationship between ocean water and the edges of ice sheets.

When predicting the potential effects of climate change in the area, it is also necessary to take into account the presence of sizable under-ice rivers.

To apply their frameworks to other regions and better understand how a changing Antarctica might affect the planet, the team is currently looking to collect more information from surveys about all these mechanisms, Phys Org reports.

The study by Dow and her colleagues was published in the journal Nature Geoscience.