KELLY MCEVERS, HOST:
It's ALL THINGS CONSIDERED from NPR West. I'm Kelly McEvers.
Neil Ross studies Antarctica. Not long ago, he found something amazing under the ice.
DR. NEIL ROSS: We discovered a huge valley underneath the West Antarctic ice sheet, which was over 300 kilometers long, more than two kilometers below sea level, with a relief of something in the order of about 3,000 meters. So deeper than the Grand Canyon.
MCEVERS: The crazy thing about this story is Ross found the valley by accident. He was on a routine research trip to Antarctica measuring the thickness of the ice. Back at home, he was checking his data when it started to become clear - this massive valley had been under his feet the whole time.
ROSS: That was a really exciting moment. And it took me a while to convince myself that what I was seeing was actually true.
MCEVERS: Ross says the valley was carved by glaciers millions of years ago. Now, it provides a record of how the Antarctic ice sheet behaved in the past when the climate was actually warmer, so studying the valley could help us know how the ice will change as the climate warms again.
ROSS: We're seeing that the ice sheets are changing in certain parts, particularly around the coastal fringes. And West Antarctica alone could change global sea levels by three meters. What we need to do is to understand how these systems might have behaved in the past. So it's a window into the past, but it also gives us a clue as to what might happen in the future.
MCEVERS: Of course, Ross says ancient ice can't predict the future. But he says one thing is certain.
ROSS: Some of the changes that we're seeing to our climate system and to our environment are amplified in the polar regions. And as a result, there has to be a real focus on these areas. And to some extent, that's happening, and that's why we're making these discoveries. We're getting people out there to make the measurements and to observe these situations and these environments, and we're learning more and more.
MCEVERS: That's Antarctic researcher Neil Ross. He is the lead author of a paper on the discovery of the valley, published this month in the Geological Society of America Bulletin.