'A lit fuse': Ancient carbon slowly seeping from permafrost could ignite climate-change bomb

© Alexander Kovalev
Slowly melting permafrost is seeping ancient carbon into the atmosphere in what researchers describe as a slowly ticking climate change time bomb.

The paper, published in Nature Geoscience on Monday, confirms that the thawing permafrost is releasing gases which have been trapped in ice for thousands of years as climate-warming greenhouse gases.

By subjecting gas captured from lakes in Alaska, Siberia and Canada to radiocarbon dating, researchers from the University of Alaska Fairbanks found the gas had been generated from carbon stored up to 30,000 years ago.

The team of scientists also used historical aerial photo analysis, soil and methane sampling, to quantify the strength of the “permafrost carbon feedback.”

Although the amount of gases being released from permafrost at the moment is “pretty small,” it’s thought that over the next 90 years, the levels of gas could be from 100 to 900 times greater than present measurements.

“It’s a lit fuse, but the length of that fuse is very long,” said lead author Katey Walter Anthony, according to the The Canadian Press.

Walter Anthony explained that model projections show that “we’re getting ready for the part where it starts to explode. But it hasn’t happened yet.”

With an estimated 1,400 petagrams of old carbon stored in permafrost, and with each petagram equalling a billion tonnes, this is about twice the amount that is currently in the atmosphere, according to Walter Anthony.

The main concern for many researchers is that if vast amounts of this old carbon are released, it could create a “feedback loop.” This means the emissions being released contribute to warming, which in turn then cause more permafrost to thaw out and more gases to be released, and so the loop continues.