NOVA

Carlisle Companies

Viking

NOVA Science Trust Logo

Greenland’s glaciers are melting faster and faster. If they were all to disappear, the sea level around the world would rise by 20 feet, scientists estimate. A FRONTLINE I NOVA I Emblematic collaboration

Greenland’s glaciers are melting faster and faster. If they all melted, it's estimated that the sea level around the world would rise by 20 feet.

Greenland’s glaciers are melting faster and faster. If they all melted, it's estimated that the sea level around the world would rise by 20 feet.

Greenland Melting

Planet Earth

Narrator: The island of Greenland is covered with an enormous ice sheet. In some places, two miles thick. If it all melted, it's estimated that the sea level around the world would rise by about 20 feet. For centuries, the ice here was relatively stable, but recently it's been melting faster and faster.NASA's scientists are trying to find out exactly how fast the glaciers of Greenland are melting and moving water into the sea. Leading the team is Josh Willis.Josh Willis: This is a dangerous place to be. This is West Greenland, 220 miles north of the Arctic Circle. And we're looking at the Avannarleg Glacier. It's a river of ice made up of snow compacted over thousands of years, and it empties right here into the ocean. At any moment, a huge chunk of ice could break off and crush a person if they were standing right here or cause a tidal wave that would sweep a person away. But this ice isn't just dangerous because it's falling. The glacial flow of a vernal lake is speeding up just like glaciers all across the world.Narrator: Fifteen years ago, this glacier was losing ice at a speed of about three feet per day. According to scientists latest measurements, it has tripled its speed, now losing 10 feet per day. And it's not the only one that is melting faster.You’re on the deck of a national research boat called the Neptune. This is the Bernstorff Fjord. Eric Rignot is a professor at UC Irvine and a senior scientist on the NASA team.Eric Rignot: In the distance, about three miles from here, is Fimbul Glacier. Fimbul Glacier didn't used to be that far; they used to be much, much closer. In fact, about 100 years ago, it was right here. The glacier retreated more in the last 15 years than in the previous 70 years. We'd like to know why. This is why we came here. We think climate warming has something to do with it and not just air temperature because air temperature is not enough to expand this retreat. We think something is happening down below in the ocean.Josh Willis: We're downstairs inside the boat; the computers behind me are connected to a sonar that's scanning the shape and depth of the sea floor. That's important because the glaciers are sitting right in the water and water is really good at melting the ice. Just imagine an ice cube melting in a glass of water as opposed to an ice cube left out on the counter in the air. The water is really good at melting ice because it contains so much heat, and the warmer the water, the faster it melts.Narrator: So to better understand how fast Greenland's glaciers will melt and raise sea level, scientists need to figure out how much of that ice is sitting underwater and how warm that water is. The NASA team is trying to measure this from the Neptune, but also from the air.Josh Willis: This is NASA 2, the Gulfstream III, that is my home for about five weeks a year when we're in Greenland and taking measurements. It's probably the most important platform we have for our mission because it allows us to get to every corner of Greenland in just a few weeks. The racks here communicate with the radar that we attach to the bottom of the plane. The radar measures the ice height and tells us which glaciers are shrinking and retreating the fastest. We also dropped probes through a tube in the back of the plane.This is where we drop the probes to this, to the fault of the sea floor and measure temperature and salinity. So when we get to the right spot, the pilot says, “Three, two, one, drop.” Pretty soon, it's radio and data back from the surface, all the way to the sea floor. It's something we've never been able to do before.Narrator: This is what the Kangerlingata Glacier in West Greenland looks like from the air. It's about two and a half miles wide. On both sides of the fjord, you can see a line of lighter colored rocks where ice used to be in the last 15 years. More than five square miles of this glacier have been lost to the sea. Parts of the glacier tower 160 feet above the ocean, but how much of this ice is sitting in the water? The data gathered by NASA provides a clearer picture.Try looking below the water's surface. It turns out that this fjord is around a thousand feet deep, meaning that most of the glacier is underwater. And here, the deeper water is warmer. The NASA research shows that warm, salty currents from the Atlantic are eating away at the glacier from below. And this appears to be happening to glaciers all around Greenland. Scientists like Josh and Eric think this could be one big reason why the ice here is breaking up and melting faster and faster.Eric Rignot: Well, when you look at the glacier like that, from the vantage point of a helicopter, it looks like it's going to be here forever. How could it possibly go away?Narrator: Out the window of this helicopter is the largest glacier in Greenland, Jakobshavn. The glacier here is about 12 miles long. Jakobshavn is world famous because it produces some of the biggest icebergs, and it is believed that the one that sank the Titanic might have come from this glacier. In the last 15 years, Jakobshavn has lost more ice than it did in the previous century, shedding ten miles worth of ice into the sea.Back in 2008, filmmakers captured an enormous chunk of ice, as wide as Manhattan, break away.Eric Rignot: The changes that we are witnessing are amazing. None of us expected to see such changes in Greenland.Josh Willis: We are just two years into this five-year-long experiment to measure how much the oceans are melting away the ice around the edges of Greenland. But we've already found out that glaciers all around Greenland sit in fjords that are much deeper than we previously knew. That means more of the ice is in contact with the ocean water and more glaciers are threatened than we previously understood.Eric Rignot: Sometimes I think about the evidence that we have gathered over the past 20, 25 years—even more the impact of climate warming on the ice sheets. And my kids and grandkids will look at me and say, “You knew this was happening. What have you done to slow it down?” I study them, and I reported the results to people. I'm not sure that was enough, but I did the best I could.Narrator: NASA's findings suggest that current predictions of how fast Greenland's glaciers are melting may be too conservative, putting coastal cities from Miami to Mumbai at greater risk of catastrophic flooding. Similar forces could be at work on the other side of the planet in Antarctica, where there is 10 times as much ice.

Greenland Melting

Support Provided By

Explore More

Antarctic Extremes

Sea Level Rise: When 1 in = 2 ft

Greenland's Disappearing Glaciers—A Tale of Fire and Ice

Scientists are about to lock themselves into an Arctic ice floe for a year

Can We Cool the Planet?

What’s Causing Greenland’s Biggest Glacier to Melt?

Transcript

Credits