'Zombie ice': Greenland’s melting glacier to raise sea levels nearly 1 foot, double previous estimate

We speak with glaciologist David Bahr, who co-authored a shocking new study this week revealing Greenland’s melting ice sheet will likely contribute almost a foot to global sea level rise by the end of the century. The report, published in the journal Nature Climate Change, finds that even if the world were to halt all greenhouse gas emissions today, 120 trillion tons of Greenland’s “zombie ice” are doomed to melt. Bahr says if global emissions continue to rise, global sea level rise just from Greenland glacial melt could reach two-and-a-half feet. “The faster we can get to net zero, the better we will all be,” he says.

"Zombie Ice": Greenland's Melting Glacier to Raise Sea Nearly 1 Foot, Double Previous Estimatewww.youtube.com

Transcript

AMY GOODMAN: This is Democracy Now!, democracynow.org, The War and Peace Report. I’m Amy Goodman, with Nermeen Shaikh.

This week a major new study revealed Greenland’s melting ice sheet will likely contribute almost a foot to global sea level rise by the end of the century — that’s twice as much as previously reported. Writing in the journal Nature Climate Change, researchers found that even if the world were to halt all greenhouse gas emissions today, higher levels of atmospheric carbon dioxide have already doomed 120 trillion tons of Greenland’s ice to melt. Without urgent action to mitigate the damage, researchers warn, sea level rise could be far higher.

For more, we’re joined by one of the report’s co-authors, David Bahr, glaciologist at the Institute of Arctic and Alpine Research at the University of Colorado, Boulder.

David, welcome to Democracy Now!

DAVID BAHR: Thank you.

AMY GOODMAN: Talk about what you found and the so-called zombie ice that you and your colleagues studied.

DAVID BAHR: Yeah, “zombie” is a good term. What we found is that the Greenland ice sheet is trying to recover from damage that we’ve already done. So we’re not even talking about future climate change. This foot of sea level rise is due to the damage we have already caused. And in order to kind of correct this damage, the ice sheet is trying to shrink and readjust its position, and this is leaving ice along the margins of the ice sheet essentially dynamically disconnected from the rest of the ice sheet. It’s dead ice. It’s already committed to the oceans. And that’s why we’re calling it “zombie ice.” It’s relegated to the oceans and to sea level rise, and there’s nothing that we can do about that now. Our best hope is just try to prepare for the future and try not to make it worse.

NERMEEN SHAIKH: And, David, explain why Greenland is so important.

DAVID BAHR: Well, there are several sources of sea level rise. One that’s underappreciated is the thermal expansion of the oceans. As we warm the atmosphere, we warm the water, and it expands, just like most things. The second-largest cause of sea level rise is now Greenland. It used to be the small glaciers. And by “small,” we mean those in the Alps, in the Himalayas, in Alaska. But Greenland is overtaking that. Those canaries in the coal mine that were the small glaciers are no longer as big a contributor as Greenland. And Greenland now is really surprising us by how much water it’s going to contribute to sea level rise.

NERMEEN SHAIKH: And, David, what can we extrapolate, if anything, from what this study finds on Greenland to other ice sheets, glaciers elsewhere in the world? I mean, right now we’re seeing these devastating, unprecedented floods in Pakistan — Pakistan, of course, home to the largest number of glaciers in the world.

DAVID BAHR: Right. Well, you know, each one of these studies shows things to be just a little bit worse than we hoped. Antarctica right now is a big question mark. We don’t want it to get a lot worse. So, the question is: Well, will it? And a similar study should be done there. The world’s small glaciers are melting at just an unprecedented rate and will continue to be a major factor in sea level rise. You know, we have to think about the climate change that’s still coming. And if we don’t tamp that down, then we’re expecting up to two-and-a-half feet of sea level just from Greenland, before we even consider these other sources.

AMY GOODMAN: Tuesday, U.N. Secretary-General António Guterres warned that the world is sleepwalking toward the destruction of the planet. He made the comment in a plea for nations to help Pakistan recover from its devastating floods that have left a third of the country underwater, have killed well over a thousand people and displaced 33 million.

SECRETARY-GENERAL ANTÓNIO GUTERRES: The government of Pakistan has asked for the international community’s help. Let us work together to respond quickly and collaboratively to this colossal crisis. Let us all step up in solidarity and support to the people of Pakistan in their hour of need. Let’s stop sleepwalking towards the destruction of our planet by climate change. Today it is Pakistan. Tomorrow it could be your country.

AMY GOODMAN: So, David Bahr, that’s the U.N. secretary-general. We see the horror that’s taking place in Pakistan. We see the heat dome in the United States, the record-breaking heat in California, fires, as well. You’ve got Jackson, Mississippi, a number of issues coming together, from race to climate. Make the connection, as a glaciologist, as a climate change scientist, to your report, the overall issue of the climate catastrophe right now, and what can be done to reverse what has happened so far.

DAVID BAHR: Yeah. Reversing is difficult, but we can mitigate. At this point, we’ve committed ourselves to a certain amount of damage. We’re going to continue to see fires. We’re going to continue to see floods. We’re going to continue to see the sea level rise that we’re expecting from Greenland. But the faster we can get to net zero, the better we’ll all be. You know, we’re expecting nuisance flooding, storm surges, loss of infrastructure along the coastline, but it doesn’t have to get a whole lot worse. You know, over the next hundred years, OK, we’re committed to one foot of sea level rise and the damage that we expect from that. But there’s no reason we need to make it worse. If we act today and start reducing our carbon emissions in a serious way, then we can avoid this worst-case scenario of multiple feet of sea level rise.

AMY GOODMAN: David Bahr, what most shocked you? I mean, you’ve been looking at glaciers for a long time. And again, your report is like twice the prediction —

DAVID BAHR: Yeah.

AMY GOODMAN: — of the Nobel Peace Prize-winning IPCC. The Intergovernmental Panel on Climate Change projected two to five inches of sea level rise from glacial melting in Greenland. Why this massive leap?

DAVID BAHR: Right. Well, you know, I was involved in the 2013 IPCC report. And so, what struck me is just the magnitude of the loss that we’re expecting, what we’re already committed to. Nobody involved with this research expected it to be double what we had thought before. That’s just really shocking. And then, if we look at the future damage, the idea that we could even get up to 30 inches of meltwater from Greenland is just shocking.

AMY GOODMAN: And can you talk about the methodology that you used in this reporting that led you to this?

DAVID BAHR: Yes. Most of the reports involved with sea level rise from Greenland involve computer models. In our case, we used observations, actual boots on the ground. There were a lot of co-authors involved. I developed some physics that we used to plug that data in that we got from the actual ice sheet. And it shows that the snow line, the dividing line between what melts each year and what accumulates snow each year, is steadily shifting upwards. And by tracking how the snow line is moving upwards, we can determine how much of that ice is just zombie ice, the ice that has one foot in the grave and is committed to sea level.

AMY GOODMAN: Solutions?

DAVID BAHR: Well, I think we all know the solutions. We have to get back down to net zero. And that requires serious government action. It’s great that we all pitch in as individuals, but without the concerted efforts of the world’s governments, we’re not going to make the kind of progress that we need to make.

AMY GOODMAN: David Bahr, I want to thank you for being with us, glaciologist at the Institute of Arctic and Alpine Research at the University of Colorado, Boulder, co-author of the new report published in the journal Nature Climate Change titled “Greenland ice sheet climate disequilibrium and committed sea-level rise.” Stay with us.