Karen Alley ’12
One of the biggest concerns of global warming is rising sea levels that threaten to destroy coastal ecosystems. A new study published by Nature Geoscience, for which glaciologist Karen Alley ’12 was lead author, is shedding light on one of the major contributors: the weakening of large chunks of ice called ice shelves.
Just as flying buttresses support Notre Dame, ice shelves help hold ice sheets in place, explained Alley, whose research was recently highlighted in the Washington Post.
When warmer water compromises the ice shelves, the glaciers that are behind them will flow more quickly into the ocean, leading to rising sea levels. With a large percentage of the world’s population living close to sea level, rising ocean levels are a huge concern. “It’s important to understand whether ice shelves are stable now and whether they will be in the future in order to predict sea level rise,” she said.
Alley, a geology major at Colgate who is now pursuing her PhD at the University of Colorado Boulder, specifically studies channels that are carved into the underside of ice shelves as fresh water melts from the bottom of a glacier. By examining satellite imagery taken over the last 10 years, Alley and her colleagues noticed that one of these channels, located on the Getz Ice Shelf in West Antarctica, was growing quickly — cutting into the base at a rate of about 10 meters per year. In another location, imagery revealed that the Getz Ice Shelf has begun to fracture at the junction of two channels. “This was alarming, because it was telling us that these channels could contribute to ice shelf collapse, which, in turn, could lead to increased sea level rise in the future.”
Going forward, Alley will be examining satellite images from the last two decades to learn more about how fast the Getz Ice Shelf is changing, and hopes that this research will prompt the glaciology field to keep a closer eye on ice shelves. “This will help us get a sense of how important ice shelves really are,” she said.
— Allison Curley Marin ’04