Robin Bell investigates why polar ice is melting

“To understand any process,” said Bell, “you have to understand it from start to end. And what we want to be able to do with ice sheets is actually model how they grow and how they collapse.”

Robin Bell is a senior scientist at Columbia’s Lamont-Doherty Earth Observatory. She’s led seven expeditions in Antarctica to study how our warming climate is changing polar ice sheets.

Robin Bell: To understand any process, you have to understand it from start to end. And what we want to be able to do with ice sheets is actually model how they grow and how they collapse.

She said three big changes have become evident in the last five years.

Robin Bell: We’re seeing the edges of ice sheets drop down. At the same time, they’re flowing towards the oceans faster. And the third signal, is one we’ve measured from space, is they’re actually weighing less.

Bell said it’s more difficult to figure out what’s actually going on inside the ice.

Robin Bell: That’s what matters a lot. It’s kind of like whether the floor is slippery or not. You have to image through all that ice sheet to be able to see what’s going on at the bottom. That’s the challenge that we’re still after, is understanding the physics at the bottom of ice sheet.

She said understanding the physics of ice sheets will help scientists predict how much ice will melt into the ocean as global temperature increases, and how sea level will rise.

Robin Bell: This is likely to be a period of increasingly rapid rising sea level, and we need to know how we need to change around the edges of our world.

Dr. Bell expanded on the three big changes scientists are seeing in the polar ice sheets.

Robin Bell: The changes that have occurred in the polar regions in the past few years have been remarkable. Mostly, we’ve seen them from satellites. We’re seeing the edges of ice sheets drop down, so they’re sort of getting lower. At the same time, we’ve measured that they’re speeding up, so they’re flowing towards the oceans faster. And the third signal, is one we’ve measured from space, is they’re actually weighing less.

She said that before scientists began a concentrated effort to study the poles, no one knew much about how ice sheets function.

Robin Bell: Our understanding of how ice sheets change is improving. But the problem is, some of the critical processes are hard to see. We have hard time seeing what’s going on in the bottom of the ice sheet. That’s what matters a lot. It’s kind of like whether the floor is slippery or not. You have to Image through all that ice sheet to be able to see what’s going on at the bottom. That’s the challenge that we’re still after, is understanding the physics at the bottom of ice sheet. Bell’s current research project, called Operation ICE Bridge, will fly over the edges of ice sheets. Instruments strapped to the belly of the plane will measure how thick the ice is, and where the rock lies underneath.

Lindsay Patterson

MORE ARTICLES