An international team has found that meltwater from beneath the Greenland ice sheet is brimming with methane.
The findings suggest glacial melt could provide substantial amounts of the greenhouse gas globally.
The research appears in the journal "Nature."
For years, scientists have thought that the ground beneath ice sheets could store methane, but climate models currently ignore the possibility.
Now, a yearlong study of outflow from beneath the Greenland ice sheet suggests it's time to update those models.
Lead author Guillaume Lamarche-Gagnon of the University of Bristol in England says the methane likely comes from living wetlands beneath the ice sheets. But it doesn't stay there.
"Because of these fast-flowing waters that drain the bed of the ice sheet, it quickly makes it to the margin and to the atmosphere. Only a small percentage of this methane appears to be consumed by bacteria, so most of it probably makes it to the atmosphere."
Previous storage and release of methane by glaciers could have affected past ice ages.
