Study says Greenland ice melt will raise sea levels by nearly a foot Transcript

Speaker 1: (00:08) A new study finds that the Greenland ice sheet is set to lose 3.3% of its mass. That's equal to 110 trillion tons of ice. The findings in the journal Nature Climate Change say this will trigger nearly a foot of global sea level rise. The study did not specify when this will happen, but researchers predict much of it can play out between now and the year 2,100. For more on this, I want to bring in Ted Scambos. He's a senior research scientist at the university of Colorado in Boulder. Ted let's kind of try to bring these numbers down into sort of more manageable form. We've known that the ice sheet has been melting, is this a case of it's melting even faster than we thought? Ted Scambos: (00:57) No, this is more a case of recognizing just how much we're committed to even with climate staying right where it is. What the study did was take the last 20 years where we have really good data, both from satellites and from weather systems, weather instruments, and looked at how Greenland has lost ice from year to year, given warmer years and cooler years. If the next 20 years are an example of what climate in Greenland is going to be like over the next few centuries, then we're in for a ice sheet that's going to shrink to the extent of about a foot of sea level rise. Speaker 1: (01:30) And what does that mean? What would that cause... What would happen? Ted Scambos: (01:35) Yeah, it has more impact the further south you go because of the way the water gets distributed over the surface of the ocean. It's not just filling up a bathtub there's places that fare worse than others. And in fact, the Southern coasts of well, the United States around Asia, the tropical belt, those areas see a little bit more sea level rise as time goes forward. What it means is that we're going to see additional sea level rise over and above what we are seeing year to year now as Greenland adjusts to the new climate. And that's assuming that climate doesn't get any warmer, which almost everybody assures that it will. Speaker 1: (02:17) And let's focus on that for a moment, what causes the sea level rise? And what's your assessment of whether that will get worse or better. Ted Scambos: (02:29) So Greenland is a large, massive ice. It was formed back when the earth was a lot cooler. It's been through some ups and downs over the past several thousand years, but now we began to really push on this warming trend and it's through greenhouse gases that have been added to the atmosphere. The perimeter of the ice sheet is melting more than it used to. You can see a large band of blue ice that's deep, high pressure ice that's beginning to erode or melt away off the sides of the continent. And the glaciers are all, especially in Southern Greenland, flowing faster than they used to. And so we're seeing both faster flow and runoff in the form of water contributing to sea level rise. That's sort of going to play out for the next several centuries, a lot of it this century, and that's what the study is pointing out. Speaker 1: (03:19) And so is that what we're... The timeframe we're talking about here is over several centuries and is that the right timeframe we should be thinking about if anybody hears about this and is alarmed and wants to take action. Ted Scambos: (03:34) So the ice sheet is finding itself in a climate and environment that it's not stable with. It has to shrink somewhat in order to have a stable size that remains constant from decade to decade. Right now there's parts of it that are sticking out at low elevation and further south that need to melt away. So a lot of this is going to happen in this century, but it's going to play out over a very long time. Now, the thing that the study didn't mention is that climate, as I said before, is almost certainly going to get warmer. So we're going to keep stepping on this accelerator pedal for ice loss and sea level rise through this century. You can say it's impossible to stop it. The way to stop it would be to go to a climate that's actually a little cooler than it is today. And that's very far in the future with a whole lot of work for the human race before we get there. Speaker 1: (04:26) And even if it gets cooler, if the climate gets cooler, that just slows the rate of loss, right? There's not a chance that there's going to be any accumulation of ice. Ted Scambos: (04:37) That's correct. It would take a very long time before the ice sheet were to regrow, geologic spans of time. It's basically up to us to start tapping on the brakes and get this under control. And I have to say, I'm pleased with some of the things that have been passed by Congress recently. I think we've taken some big steps in the right direction. Speaker 1: (05:00) All right, Ted Scambos thanks so much for helping us understand this. Ted Scambos: (05:04) Sure. Thank you.