Scientists were surprised to find a giant river flowing under the Antarctic ice sheet. Building on previous observations, the latest study further demonstrates how an interconnected network of rivers, lakes, and marine ecosystems can be found deep beneath this largely inaccessible and studyable chunk of the planet.
This river was recently discovered by researchers at Imperial College London, University of Waterloo, Canada, Universiti Malaysia Terengganu, and University of Newcastle. In a new study, the team used modeling and geophysical data from aerial radar surveys to measure the size and dynamics of this colossal river.
In the study, published in the journal Nature Geoscience, their results show that the river stretches about 460 kilometers, transporting large flows of fresh water at high pressure.
"When we first discovered lakes beneath the Antarctic ice decades ago, we thought they were isolated from each other. Now we're starting to understand that there's a whole system down there, interconnected by a vast network of rivers, as might otherwise be the case. there are thousands of meters of ice on it," said Professor Martin Siegert, study co-author from the Grantham Institute at Imperial College London.
One way in which water can emerge beneath an ice sheet is from water on the surface that melts and flows down through deep crevices. This is what is happening beneath Greenland in the Arctic, which sees a lot of melting during the summer months.
In Antarctica, summer is not cold enough for this to happen. This led scientists to believe that there would be less water at the bottom of the Antarctic ice sheet. However, it appears that large amounts of water did emerge here, primarily driven by melting at the base of the ice sheet caused by the Earth's natural heat and friction as the ice moved over land.
As exciting as this discovery may be, rivers under flowing ice have the potential to damage the ice sheet by accelerating ice loss as the climate warms. The researchers are also interested in seeing how the presence of rivers might influence predictions about how Antarctica will change in the face of climate change.
Model of a river system found under the Antarctic ice sheet. Photo: Dow et al. 2022
"The area where this research is based has enough ice to raise sea levels globally by 4.3m. How much this ice melts, and how fast, is related to how slippery the ice bed is. Newly discovered river systems can greatly influence this process." Siegert explained.
The existence of this river and other rivers like it also needs to be taken into account when predicting the possible impacts of climate change in the region.
"From satellite measurements, we know which regions of Antarctica are losing ice, and how much, but we don't always know why. This discovery could be the missing link in our model. We can greatly underestimate how fast the system will melt by not taking into account the effects this river system.
"Only by knowing why the ice is disappearing can we make models and predictions about how the ice will react in the future under further global warming, and how much this could increase sea levels globally," added lead researcher Dr Christine Dow from the University of Waterloo.
