Greenland is melting.
Scientists have known this for a long time… but they're still astonished by what they say happened there earlier this month—what NASA is calling an "extreme melt event."
On a single day, 97 percent of Greenland's vast ice sheet was covered with water.
Scientists have never seen anything like it. And what happens in Greenland could have a big impact on those of us who live in coastal areas around the world.
Anchor Aaron Schachter talks to The World's environment editor Peter Thomson to get more details.
SCHACHTER: Peter, what's going on up there?
THOMSON: Well Aaron, the NASA scientist who first spotted this big melt is calling it "extraordinary." In fact he said it is so extraordinary that at first he thought the satellite data he was looking at was wrong. So he cross checked with other data from other satellites and he confirmed that what he was seeing was real—nearly the entire surface of the Greenland ice sheet was melting all at the same time.
Now I should say a good deal of the ice surface up there melts a little bit every summer, maybe as much as half of it, but this was off the charts. And it happened very quickly. NASA says that there was melting over about 40% of the ice surface on July 8, but that in just four days, by July 12, it had spread across just about the entire ice sheet.
SCHACHTER: And this was global warming, right? That's what's causing this?
THOMSON: Well, NASA says this big melt coincided with what calling a "heat dome." They're not using the words "global warming," they're saying it's part of a pattern of extremely warm weather that's been passing over Greenland all of this summer. In fact it's a lot like the hot, dry weather that's been parked over a lot of the U.S. this year and that's been bringing us this terrible drought. So—global warming? That's certainly a question that's lurking in the background.
SCHACHTER: What is being said is this word "extraordinary." But at the same time it isn't exactly unprecedented.
THOMSON: Right, I mean, no living scientist has ever witnessed anything like this before. But folks who've drilled into the ice in Greenland have essentially been able to go back in time by analysing the layers of ice put down over the years, and they've found that a big melt like this has happened before—in fact it happens roughly every 150 years, and the most recent one was in 1889. So they're saying that in a sense, this one was right on time.
Having said that, there's so much going on in and around Greenland right now that you can't just say, well this is normal, so don't worry about it. Greenland is the largest chunk of ice outside of Antarctica and it's been melting around the edges for years. That is climate change, there's really no doubt about that, and no one really knows how quickly it's going to start shedding significant amounts of water into the ocean and really effecting sea levels.
What they are saying about this event is that one time is worth paying attention to, but that if it happens again soon, that would really be something to worry about.
And I have to say that there's a sort of haunting echo here of what was supposed to be another very unusual event in Greenland. A huge chunk of ice broke off an important glacier in northern Greenland, called the Peterman glacier. Scientists said pretty much the same thing at the time—its worth paying attention to, probably not something to worry about just yet. Well, two years later, just a few weeks ago, another huge chunk broke off of the same glacier.
SCHACHTER: Right, and the concern is that all of this will cause sea levels to rise and no one is sure exactly what will happen to coastal areas around the world but it seems like a bad thing. With this big ice melt, is that contributing to the rise in sea level?
THOMSON: Probably not in any significant way. I mean, right now most of the ice that melted froze up again almost right away. Around the edges of Greenland, some of it does run right off into the sea, but not in large amounts. The bigger concern though is water that seeps down into the ice sheet through cracks and crevasses. If it gets all the way to the bottom, where the ice meets the bedrock, it can help sort of lubricate the ice and help it flow faster.
Another concern is that when water goes down into those crevasses, it freezes, it expands, and it pushes the crevasses open just a little bit more. It's sort of like what happens when potholes are formed in a road. Water gets into a crack in the tar, it freezes, it pops it open. So every time water seeps into a crack or a crevasse on a glacier, it expands that crack or crevasse just a little more and makes it more that much more vulnerable to it happening again.
SCHACHTER: OK—bottom line—sounds scary. Should we be worried , or shouldn't we be worried?
THOMSON: Well let's just say we shouldn't be any more worried today than we were about what's going on in Greenland. This was an extraordinary event, not necessarily one to suddenly start running around and saying the sky is falling, but what's happening in Greenland is very serious and very scary over a timeframe of, you know, maybe not even 100 years.
SCHACHTER: The World's environment editor Peter Thomson, thanks very much.
THOMSON: You're welcome, Aaron.