Large methane release could cause abrupt climate change as happened 635 million years ago

UCR-led research team says methane-triggered global warming ended last 'snowball' ice age; dramatically reorganized Earth system

Dolomite cement, formed from oxidized methane as it evolved from melting methane hydrates at the end of the snowball Earth glaciation, present in wave-cut platforms at Marino Rocks, South Australia.... Click here for more information.

RIVERSIDE, Calif. – An abrupt release of methane, a powerful greenhouse gas, about 635 million years ago from ice sheets that then extended to Earth’s low latitudes caused a dramatic shift in climate, triggering a series of events that resulted in global warming and effectively ended the last “snowball” ice age, a UC Riverside-led study reports.

The researchers posit that the methane was released gradually at first and then in abundance from clathrates – methane ice that forms and stabilizes beneath ice sheets under specific temperatures and pressures. When the ice sheets became unstable, they collapsed, releasing pressure on the clathrates which began to degas.

“Our findings document an abrupt and catastrophic means of global warming that abruptly led from a very cold, seemingly stable climate state to a very warm also stable climate state with no pause in between,” said Martin Kennedy, a professor of geology in the Department of Earth Sciences, who led the research team.

Geologists Chris von der Borch (front) and David Mrofka (back) look for evidence of ancient methane seepage within tidal sediments seen in sea cliff exposures at Marino Rocks, South Australia. Click here for more information.

“This tells us about the mechanism, which exists, but is dormant today, as well as the rate of change,” he added. “What we now need to know is the sensitivity of the trigger: how much forcing does it take to move from one stable state to the other, and are we approaching something like that today with current carbon dioxide warming.”