Zombie ice from the massive Greenland ice sheet will eventually raise global sea level by at least 10 inches on its own, according to a study released Monday.
Zombie or doomed ice is ice that is still attached to thicker areas of ice, but is no longer getting fed by those larger glaciers. That's because the parent glaciers are getting less replenishing snow. Meanwhile the doomed ice is melting from climate change, said study co-author William Colgan, a glaciologist at the Geological Survey of Denmark and Greenland.
Time is the key unknown here and a bit of a problem with the study, said two outside ice scientists, including Leigh Stearns of the University of Kansas. The researchers in the study said they couldn't estimate the timing of the committed melting, yet in the last sentence they mention, “within this century,” without supporting it, Stearns said.
One of the study authors said that more than 120 trillion tons of ice is already doomed to melt from the warming ice sheet’s inability to replenish its edges. When that ice melts into water, if it were concentrated only over the United States, it would be 37 feet deep.