Greenland’s ice adds about a millimeter of water per year to the world’s ocean, according to NASA, making it the largest contributor to rising sea levels. With over 24 feet of ice, Greenland has a lot more to give. But scientists don’t have an idea of how quickly that ice could melt.
That’s where NASA’s OMG mission—”Oceans are Melting Greenland”—comes in. They intend to carefully measure how the landmass’s glaciers shrink and use that information to better predict what future melting might look like.
Now, the first of the data is coming in, and NASA scientists and affiliated university researchers have published two new studies in the journal Oceanography.
OMG uses ships, planes, and other research tools to understand what’s happening when warm, deep layer of water from the Atlantic encounters Greenland’s 27,000 miles of coastline. Here’s Chris Mooney, reporting for The Washington Post:
Basically, it works like this: Waters swirl in a broadly clockwise rotation around the enormous island, often darting inward toward the outlying glaciers along the way. And in fjords that are the deepest, the Atlantic layer, which tends to be over 200 meters (more than 650 feet) deep, has the greatest chance of causing sustained melting.
“Where it’s deep, there’s warm water,” says [principal investigator Josh] Willis. Above the Atlantic layer, meanwhile, is a layer of colder polar water that has far less of an effect on glaciers — meaning that the big and thick glaciers often get hit hard at their bases, even as the small and thin ones don’t necessarily get hit much at all.
Researchers still need comprehensive data on the depths and shapes of the fjords, the thickness of the glaciers, and typical ocean behavior of where water meets land. Then, they will feed that information into a computer simulation that projects climate change to the year 2100.
It’s too early to run the model, said Mathieu Morlighem, lead author of one of the papers and researcher at the University of California, Irvine. We may have to wait another year or two before the computer can predict the future of Greenland’s icy coasts.
Still, the big picture NASA’s new data suggests is that there are new vulnerabilities. Numerous glaciers extend deeper beneath the ocean, and other glaciers are more vulnerable to warming than previously thought.
“These kinds of results suggest that we could be in for more sea level rise than we thought,” Willis told Mooney. “And we’re not alone; the fact is that almost every time some new results come out of Greenland or Antarctica, we find these glaciers are more vulnerable than we thought.”
