Methane caused ‘abrupt and catastrophic’ warming

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Methane belching out from beneath ice sheets caused a dramatic shift in Earth’s climate, ending the last ‘snowball’ ice age, scientists report in this week’s edition of the journal Nature.

Unstable and collapsing ice sheets allowed frozen pockets of methane to erupt to the surface, then into the atmosphere, the researchers concluded. Methane is a far more damaging greenhouse gas than carbon dioxide, the most frequently referenced culprit of planetary warming.

‘Our findings document an abrupt and catastrophic global warming that led from a very cold, seemingly stable climate state to a very warm, also stable, climate state -- with no pause in between,’ said geologist Martin Kennedy of the UC Riverside, who led the research team funded by the National Science Foundation.

The authors of the study warn that such releases created a runaway feedback that rapidly accelerated warming past a tipping point.

‘Today we’re conducting a global-scale experiment with Earth’s climate system,’ Kennedy said, ‘and witnessing an unprecedented rate of warming, all with little or no knowledge of what instabilities lurk in the climate system and how they can influence life on Earth.

‘Much the same experiment was done 635 million years ago, and the outcome is preserved in the geologic record. We see that strong forcing on the climate, not unlike the current carbon dioxide forcing, results in the activation of latent controls in the climate system that, once initiated, change climate to a completely different state.’

-- Geoffrey Mohan