A recent study by scientists suggests that up to 4 billion tones of methane gas may be locked under the Arctic ice, the Guardian reports. Scientists say the gas could be released into the atmosphere if enough of the ice melts away, adding to global warming.
Research indicates that ancient deposits of organic matter may have been converted to methane by microbes living in low-oxygen conditions.
The organic material dates back to a period 35m years ago when the Antarctic was much warmer than it is today and teeming with life.
The amount of frozen and free methane gas beneath the ice sheets could amount to 4bn tonnes, the researchers estimate.
Disappearing ice could free enough of the gas to have an impact on future global climate change, scientists believe.