In the first study to consider the long-term evolution of the rivers that flow beneath glaciers, researchers have new insights into the future of Antarctica's melting ice that may change the way climate scientists predict the effects of a warming planet.
Researchers from the University of Waterloo's Faculty of Environment led the project that studied Aurora Subglacial Basin and modelled its subglacial hydrology -the flow of water at the base of the ice. They compared drainage systems at various times ranging from 34 million years ago to 75 years from now.
The Waterloo-led team studied Aurora Subglacial Basin, one of the most rapidly changing areas on the continent.
(Photo credit: University of Waterloo)
They found that these rivers are dynamic, changing from one period to another. Aurora Subglacial Basin is in East Antarctica and is grounded below sea level, a particularly unstable configuration that could lead to rapid and irreversible retreat, and an increase of 4 metres in the global ocean level if all the ice in the region melted.
"Many studies say the past is an analogue of what might happen in the future. But if we don't now consider subglacial rivers, we're missing out on a critical part of the picture," said Anna-Mireilla Hayden, a PhD candidate and the first author of the study. "It's important that scientists who model ice sheets account for hydrology because it could reduce uncertainty in estimates of sea level rise."
The research revealed that the water pathways beneath glaciers have relocated and will continue to shift in the future. Changes in where the river drains into the ocean can impact water circulation beneath floating ice and enhance weaknesses in the vulnerable regions where ice flows from the land into the ocean. It could cause the ice to break off and contribute to even faster ice flow and greater increase in the rise of the world's oceans than previously suggested.
"It's critical that projections of sea level rise include as much relevant information as possible so that the world can take appropriate measures to lessen the devastation to global coastal communities," said Dr. Christine Dow, professor in the Faculty of Environment and Canada Research Chair in Glacial Hydrology and Ice Dynamics. "While we do not directly predict the amount seas will rise in this study, our analysis over extensive time periods of history illustrates that the influence of these subglacial rivers is both significant and highly changeable over time. The role of subglacial water in ice dynamics must be part of the conversation, or else we don't have the full picture."
Dr. Tyler Pelle, a postdoctoral researcher at Scripps Institute of Oceanography in the U.S., contributed to this work. The study, The past, present, and future evolution of Aurora Subglacial Basin's subglacial drainage system, appears in Nature Communications.
(Banner image credit: Dr. Felicity McCormack, SAEF/Monash University)
