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‘Vast Reservoir’ of Greenhouse Gas Methane Trapped Under Antarctic Ice Sheet

Posted on the 30 August 2012 by Periscope @periscopepost
Antarctic ice sheets are covering vast reserves of methane gas - which when released, could further worsen global warming. Antarctic ice sheets are covering vast reserves of methane gas – which when released, could further worsen global warming.

The background

A recent study from the University of Bristol suggested that a massive reservoir of greenhouse gas methane is lurking under the Antarctic ice sheet – and if released, could seriously accelerate global warming.

The study, led by Professor Jemma Wadham and published in the journal Nature, showed that deposits of millions of years old organic matter, left over from the Antarctic’s more verdant years, may have been metabolised into methane by micro-organisms living in those oxygen-deprived conditions. Up to 400 billion tonnes of the gas could be trapped under the ice sheet, at a shallow enough depth that could make their release into the atmosphere as the ice melts a lot more likely.

The experiment

Live Science detailed the methodology of the experiment that provided the basis of the study: “[They] sawed chunks of sediment from the fringes of an Antarctic glacier, where the ice was much thinner. They melted the ice and identified the methane-producing microbes living in the sediment. They also placed the slurry in a cold, dark, oxygen-free environment for two years, and measured how much methane the microbes produced at several points in time.” These analyses were then used to estimate the amount of greenhouse gas produced over millions of years under Antarctica.

Should we worry? Probably

According to the press release issued by the University of Bristol, “If substantial methane hydrate and gas are present beneath the Antarctic Ice Sheet, methane release during episodes of ice-sheet collapse could act as a positive feedback on global climate change during past and future ice-sheet retreat.” In other words, releasing a whole shedload of methane gas, which stays in the atmosphere for up to 15 years and is capable of trapping 20 times more heat than carbon dioxide, will make the Earth warmer, faster. What’s more, the estimated 400 billion tonnes trapped under the ice dwarfs the measly 600 million tonnes of carbon released through yearly methane emissions like wetlands, livestock, biomass burning and agriculture.

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