A heatwave inside the Arctic circle last year triggered the release of methane gas from limestone bedrock, sparking fears that rising temperatures in cold northern climates could generate larger-than-expected emissions of powerful greenhouse gases.
Scientists have long worried that rising temperatures in Arctic regions will cause the permafrost – ground frozen solid all year round – to melt.
As the frozen plants and animals trapped in the ground melt and decay, they emit bursts of planet-warming methane. The thawing of these soils could alone raise global temperatures by 0.2C.
But scientists now believe high temperatures can also cause ice trapped in rock sediment to melt, unblocking plumes of “deep methane” that have spent millions of years trapped underground.
In June last year temperatures in the Russian town of Verkhoyansk reached 38C – an event scientists deemed almost impossible without the impacts of climate change.
In a paper published in Proceedings of the National Academy of Sciences, researchers from the University of Bonn in Germany found “significantly elevated” concentrations of methane in the air above the limestone bedrock of Siberia in the months following the heatwave.
“I would have expected elevated methane concentration in wetlands, or where the soils are very thick… but it was very surprising that we saw elevated methane in the area with the rock,” the paper’s lead author, Professor Nikolaus Froitzheim told i.
“The question is where does this additional methane come from? It must come from below. The only likely explanation is that this is deep gas, natural gas from reservoirs.”
More research is needed to establish how much natural gas could be released from rocks as temperatures rise, and what impact it could have on global efforts to halt climate change.
However, early estimates suggest there is a huge quantity of natural gas trapped underground in northern Siberia. If it were to escape, it could trigger more warming that could push the Earth’s systems past new “tipping points” generating even more dangerous climate change
“I’m worried,” admitted Professor Froitzheim. “We really don’t want this additional methane.”
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