Big Sky resident authors climate change study in Science magazine
By Emily Stifler Explorebigsky.com Managing Editor
SEATTLE—Greenland's contribution to rising sea level in the 21st century might be significantly less than some scientists thought possible, according to new research. The study, published by Big Sky resident Twila Moon, focuses on changes in the speed ice travels in more than 200 of Greenland’s outlet glaciers.
"So far, on average we're seeing about a 30 percent speedup in 10 years," said Moon, who is working toward a Ph.D. in Earth and Space Sciences at the University of Washington.
Moon was lead author of a paper documenting the observations published May 4 in Science, one of the most influential magazines in physical and biological sciences.
Although she’s done fieldwork on the Greenland ice sheet in the past, this research is based on satellite data. For Moon, that means it’s all computer based and she can work from her Big Sky home half the year.
“The whole paper got written sitting in my home office, looking at whatever weather was coming over from the west,” she said.
Moon thought of the project when she started graduate school in 2010, and was drawn to it because of an interest in climate science and how climate change will impact the planet, she said.
The Greenland and Antarctic ice sheets hold “unimaginable amounts of ice,” Moon said, describing them as a “Mars on Earth sort of place,” in that there are still basic unanswered questions about them.
At this point, she said, ice sheets remain one of the biggest questions in predicting future sea level rise. Moon and her peers know that the faster the glaciers move, the more ice and meltwater they release into the ocean, and “the potential sea level rise from losing ice from those ice sheets is going to have impact all over the world.”
In the study, Moon and her co-authors created a decade-long record of changes in Greenland outlet glaciers by producing velocity maps with data from Canadian, German and Japanese satellites. They started during the 2000-01 winter and repeated the process for each winter from 2005- 06 through 2010-11, and found the outlet glaciers hadn’t increased in velocity as much as previous studies speculated.
The record showed a complex pattern. Nearly all of Greenland's largest glaciers that meet land move at top speeds of 30 to 325 feet a year, and their changes in speed are small because they’re already moving slowly.
Glaciers that terminate in fjord ice shelves move at 1,000 feet to a mile a year, but didn’t gain notable speed during the decade.
In the east, southeast and north - west areas of Greenland, glaciers that end in the ocean can travel seven miles or more in a year. Their changes in speed varied during the decade, and some even slowed. In the northwest they increased by 28 percent on average, and 32 percent in the southeast.
But the scientists saw no clear indication that the glaciers would stop gaining speed during the rest of the century.
“It’s a pretty hot topic field, and there’s a lot happening in it all the time,” Moon said. “It’s fun to be working on the very frontier of this sort of science.”