Antarctica—you’re probably not going to be surprised to learn—has a lot of ice. So much ice, in fact, that if all of it were to melt, sea levels would rise by 200 ft. (60 m)—more than enough to swamp every coastal city in the world. Even in the most extreme global warming scenarios, though, that likely wouldn’t happen for centuries, but the ice sheet in West Antarctica is melting right now, faster than any other part of the frozen continent. It’s melting fast enough to contribute nearly 10% of global sea level rise, but researchers have never really understand why West Antarctica has become such a melting hot spot.
Well, here’s a possibility: a team of British researchers have discovered a rift in the rock of West Antarctica that runs as deep as the Grand Canyon. The Ferringo rift as its called is bringing more warm sea water into the interior of the Antarctic ice sheet, which can hasten melt. “The areas that are most vulnerable [to ice melt] coincide with the areas of ancient rifting,” Robert Bingham, the discoverer of the Ferringo rift and a glaciologist at the University of Aberdeen, told NBC News. The rifting “preconfigures the topography to a shape that encourages ice loss.” In other words, the Grand Canyon of the Antarctic is setting the stage for even faster ice loss than would happen otherwise.
If it seems surprising that a canyon 6 miles (10 km) across, at least 62 miles long (100 km) and nearly a mile (1.5 km) deep would somehow escape detection all these years, well, Antarctica is a really big place that humans have only begun to understand. (Don’t forget that it was less than 100 years ago that explorers first made it to the South Pole—check out these Google Earth images from the camps—and remember that the canyon is filled with ice.) The area where the Ferringo rift was found had only been visited once before, some 50 years ago. Bingham and his field assistant Chris Griffiths were the second when they traveled to the area during a grueling 1,500 mile field trip in 2009/10.
The research expedition was meant to measure the topography of the rock beneath the ice—important scientific work, but hardly groundbreaking. But just a few days into the trip, radar equipment found that the bed of ice was becoming increasingly thick, indicating a canyon below. And it was a massive one—though unlike the Grand Canyon, shaped by erosion, the Ferringo rift is created by the forces of continental rifting, fissures deep in the Earth.
Here’s Bingham explaining the rift in a short video:
Bingham and his colleagues reported on the Ferringo rift in a paper published in Nature on July 25. But while the research is clearly a victory for topographical knowledge—seriously, there was a Grand Canyon-sized hole in the Earth no one knew about—it matters more for sea level rise. As Bingham and his co-authors write in Nature, the rift’s “existence profoundly affects ice flows.” The rift allows more warm sea water to get between the Antarctic bedrock and the ice that lies on top of it. The sea water acts as a lubricant, allowing the ice to flow faster into the sea. Glaciers spitting out ice into the sea is a natural process—that’s how we get icebergs—but the rate impacts melting, as David Vaughn of the British Antarctic Survey told the BBC:
We know that the ice loss from the West Antarctic Ice Sheet is governed by delivery of warm water, and that the warm water is coming along channels that were previously scoured by glaciers.
So the geology and the present rate of ice loss are intricately linked, and they feed back – if you have fast-flowing ice, that delivers ice to the edge where it can be impacted by warm water, and warm water makes the ice flow faster.
Scientists still need, in the words of Bingham, “more data” to understand how the rift affects the mechanisms that control melting in West Antarctica, and how climate change is affecting all of this. But coming just a few days after scientists also reported that Greenland was experiencing a record ice-loss event, what we know so far isn’t comforting.