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A sleeping giant?

methane.jpgOne noteworthy observation at December’s AGU conference – the latest and largest ever gathering of earth and space scientists – was the attention being given to a threat conceivably worse than carbon dioxide. In numerous talks, during poster sessions and over coffee, scientists were discussing methane – a greenhouse gas with a warming potential 25 times that of CO2.

Researchers have long speculated that climate change will unleash vast stores of the gas from where it lies frozen beneath the sea floor and locked up in the Arctic, triggering rapid warming.

Until recently, however, there has been little cause for concern. But that could all be changing, reports Amanda Leigh Mascarelli in a feature online today (no subscription required). Several observations made in 2007 to 2008 and reported at the AGU suggest that we could be in danger of waking a sleeping giant.

For one, a group of researchers working in the shallow waters of the Siberian Shelf noticed that their methane measurements were usually high compared with previous observations made in the same location. Added to that, they saw large rings of gas — sometimes as wide as 30 centimetres in diameter — trapped in ice, as well as plumes bubbling to the ocean surface over hundreds of square kilometres.

Then a separate group of scientists reported that global atmospheric concentrations of methane had spiked in the same year, following almost a decade of stability. While scientists can’t say whether either of these observations are anomalies or part of a long-term trend, they are certainly paying closer attention to the problem than ever before. “If there’s a ticking bomb in the room, you’d like to know the possibility of it going off,” says geochemist James White of the University of Colorado. “The fact that it’s there at all is unnerving.”

Mascarelli’s feature gives the low-down on the latest science – from the role of methane in past warming events to projections of what might occur in the future – and looks at what experts are doing to avert the problem. Some intriguing approaches abound, from parts of re-wilding Siberia with large animals that literally stomp the permafrost to keep it intact to using natural methane leaks as a power source for remote villages.

But if understanding the methane problem sounds like all work and no play, think again. Katey Walter of the University of Alaska, whose work is featured by Mascarelli, has produced some amazing videos while studying methane bubbling up from lake bottoms in the Arctic. Here her team drills through lake ice, then lights the escaping methane.

Anna Barnett and Olive Heffernan

Image: The average atmospheric concentration of methane shot up suddenly in 2007, having remained stable for a decade. Data shown are from the Advanced Global Atmospheric Gases Experiment and the Australian Commonwealth Scientific and Industrial Research Organisation, courtesy of Matt Rigby.

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