Permian-Triassic extinction event in context with other such events

Carbon dioxide gets most of the climate change press. But methane is a far more potent greenhouse gas. Climate scientists have long studied it as an indicator of CO2 levels and a possible co-conspirator in a number of dramatic extinction events correlated to a sharp increase in global temperatures, most notably the Permian-Triassic event. Recent data suggests there is reason to be concerned:

“Some of the methane and carbon dioxide concentrations we’ve measured have been large, and we’re seeing very different patterns from what models suggest,” Miller said. “We saw large, regional-scale episodic bursts of higher-than-normal carbon dioxide and methane in interior Alaska and across the North Slope during the spring thaw, and they lasted until after the fall refreeze. To cite another example, in July 2012 we saw methane levels over swamps in the Innoko Wilderness that were 650 parts per billion higher than normal background levels. That’s similar to what you might find in a large city.”

Ultimately, the scientists hope their observations will indicate whether an irreversible permafrost tipping point may be near at hand. While scientists don’t yet believe the Arctic has reached that tipping point, no one knows for sure. “We hope CARVE may be able to find that ‘smoking gun,’ if one exists,” Miller said.

In addition to the CO2 this could signal, large stores of methane are locked away in the oceans as methane hydrate and in the Arctic permafrost. If the ambient temperature in those locations were to rise just a bit, some or all of these stores could be released, adding significant momentum to the climate forcing already in progress due to human emissions. For more discussion see FishOutofWater’s diary here.