In Greenland, a climate change mystery with clues written in water and stone
By Ari Daniel
24 January 2016 (PRI) – The breakfast on the edge of Greenland’s massive ice sheet is ordinary — granola, yogurt, bread and jam. Everything else here is anything but. “You’d pay a million bucks for a view like this,” says Gordon Hamilton, from the University of Maine by way of Scotland. “Pretty nice breakfast buffet, I guess, for sitting out here next to the ice sheet.” Hamilton, Detective No. 1 in our Greenland mystery, is sitting on the rocky rim of a glacier. Kind of figures. After all, the man is a glaciologist. But this isn’t just any glacier. It’s the Helheim glacier, one of Greenland’s biggest, a three-mile-wide river of mottled gray, whites and stunning blue ice that flows into Sermilik fjord on the island’s southeast coast. We’re on one side of that fjord. Across, on the other side, is what drew us here — a horizontal stripe running the length of the fjord, about 600 feet above the ice. “Everybody who’s come here with me has said, ‘What’s that line over there?’” Hamilton says. “And I say, ‘Well, that’s where the glacier was in 2003.’ It’s kind of like the signal clue that something really big had happened.” Hamilton calls this clue the bathtub ring. Helheim’s surface sat right around the line for decades, maybe longer. But about a decade ago, he says, in the span of just a couple of years, it dropped dramatically and thinned out. “And what that means is that all that volume of ice, from the current surface up to the height of that bathtub ring, is now in the ocean.” Hamilton wants to know why, and what that big drop might mean for all of us. Because it’s not just Helheim. Most of Greenland is covered by a massive block of ice, so big it’s difficult to imagine, even right here on the edge of it. Helheim is just one of thousands of glaciers that drain that ice sheet into the sea, and right around the time the bathtub ring showed up, some of the other big glaciers also changed suddenly. “They retreated very quickly back up their fjords,” Hamilton says. “Their flow speed doubled or tripled. And this had the effect of putting more icebergs into the ocean. And when you put icebergs into the ocean, you displace ocean water and you cause sea levels to rise. [more]
In Greenland, a climate change mystery with clues written in water and stone
