Greenland is on track to lose more than 3 percent of its ice sheet, triggering almost 11 inches of sea-level rise — and scientists say there's nothing that can be done to stop it.
"It's dead ice. It's just going to melt and disappear from the ice sheet," William Colgan, a glaciologist at the Geological Survey of Denmark and Greenland, told the Associated Press. "This ice has been consigned to the ocean, regardless of what climate (emissions) scenario we take now."
A new study, co-authored by Colgan and published in Nature Climate Change, doubles previous forecasts of how much sea level rise the melting Greenland sheet could contribute to the world's oceans. A report from the Intergovernmental Panel on Climate Change (IPCC) predicted a range of rise from 6 to 13 centimeters, or 2 to 5 inches, by 2100. The recent study projects 10.6 inches at least with a possible maximum of 30 inches. It did not specify a timeframe.
The reason for this loss and subsequent sea level rise is ice that's "starving," Colgan said, meaning there isn't enough snowfall to replenish the melting ice along the glacier's edges. Regardless of how aggressively the world cuts greenhouse gas emissions, the researchers say, roughly 3.3 percent of the ice sheet — or 120 trillion tons (110 trillion metric tons) of ice — will be lost.
That loss and a corresponding 10.6 inches of sea-level rise would devastate coastlines worldwide and contribute to even more extreme weather. According to the Environmental Protection Agency, rising sea levels erode shorelines, inundate aquifers with salt water, increase the vulnerability of coastal infrastructure, and contribute to more coastal flooding. In fact, the rate at which waters meet or exceed flood levels in many coastal U.S. cities has already crept up in past decades. Boston used to have fewer than three flood days per year prior to 1969. Between 2010 and 2020, that number jumped to more than 12, according to the EPA.
Warming and rising oceans are also likely to contribute to more incidences of extreme weather. Fueled by warming oceans, hurricanes and Nor'easters are likely to grow stronger, pushing storm surges further inland. Storm surges, or the flooding during a hurricane, are already the most dangerous component of a storm, according to the Smithsonian.
As dire as that sounds, 10.6 inches of sea level rise, predicted in the study, is just a best-case scenario. The year 2012 was especially unbalanced for ice melt and replenishment. If the world has more years like that, the melting Greenland ice sheet could trigger 30 inches of sea level rise.
"That's how climate change works," Colgan told Associated Press. "Today's outliers become tomorrow's averages."