A massive glacier up to 80 miles long in East Antarctica is shrinking at an alarming rate, but the record-setting landscape beneath it could speed up its demise even more.
The Denman Glacier has retreated three miles over a 22-year period, and researchers are concerned this could be just the beginning of a total meltdown that would cause global sea levels to rise a whopping five feet (1.5 m).
The fate of Denman is tied up in not just climate change and our warming planet, but also in its foundation. The glacier’s western flank sits atop the recently-identified deepest land canyon on Earth, an ice-filled trough that extends over two miles below sea level.
Researchers from the University of California, Irvine (UCI) and NASA’s Jet Propulsion Laboratory write in a paper published this week in Geophysical Research Letters that the trough and the slope of the bed on the western flank make it conducive to accelerated retreat.
“Because of the shape of the ground beneath Denman’s western side, there is potential for rapid and irreversible retreat, and that means substantial increases in global sea levels in the future,” said lead author Virginia Brancato from NASA, who was previously a postdoctoral scholar at UCI.
The bed beneath the glacier is unusual for eastern Antarctica. The floating extension of the ice over the ocean was also found to be melting at an above average rate for East Antarctic ice shelves.
Co-author Eric Rignot, an earth system science professor at UCI, said they will keep an eye on the glacier even as much anxiety is focused on the other side of the continent.
“The ice in West Antarctica has been melting faster in recent years, but the sheer size of Denman Glacier means that its potential impact on long-term sea level rise is just as significant.”