#Melting Arctic permafrost contains 4 times the amount of carbon emitted by humans

As if there wasn’t enough to worry about, scientists have warned of a ticking time bomb in the Arctic that threatens to cause a climate catastrophe.

Frozen soil in the region contains over four times more carbon than that released by humans in the form of greenhouse gases, research shows.

As the permafrost melts due to global warming, this dump of CO2 will be released into the atmosphere, further accelerating planetary heating, ScienceAlert reports.

The finding from the University of Copenhagen suggests that the amount of carbon stored in Arctic soil is dramatically higher than prior estimates.

“Rising global temperatures are causing permafrost in the northern hemisphere to thaw and release CO2 that has been stored within it for thousands of years,” according to a Uni of Copenhagen press release.

“The amount of carbon stored in permafrost is estimated to be four times greater than the combined amount of CO2 emitted by modern humans.”

The researchers collected three deep soil samples over three years from an ancient bog near Abisko, a Swedish town within the Arctic Circle.

They were there to investigate the possible role that bacteria plays in unleashing carbon locked up in permafrost.

It’s thought that iron-eating microbes may break down the bonds that bind iron to carbon in the soil, blocking CO2 from reaching the atmosphere.

The scientists confirmed that this process is underway – and it’s getting worse as the planet heats up.

That’s because rising temperatures are further activating the bacteria, potentially destabilising the whole carbon sink.

It means that a thawing Arctic may in fact release far more carbon than even scientists’ worst-case models have predicted.

“What we see is that bacteria simply use iron minerals as a food source,” the University of Copenhagen’s Dr. Carsten W. Müller said.

“As they feed, the bonds which had trapped carbon are destroyed and it is released into the atmosphere as greenhouse gas.”

He added: “At the same time, the melted ice permits access to bacteria. As a whole, this is what releases stored carbon as CO2.”

The precise role that iron plays in restricting the release of permafrost-bound carbon into the atmosphere remains a mystery.

The researchers hope to carry out further examinations of this mechanism in future.

They said their discovery may force climate scientists to rethink the global warming models they’ve relied on for years.

“This means that we have a large new source of CO2 emissions that needs to be included in climate models and more closely examined,” Dr Müller said.

The research was published in Nature Communications.

The rapid thawing of permafrost has major implications for climate change.

The Arctic is one of the world’s biggest carbon sinks, housing an estimated 1,400 gigatons of carbon frozen in permafrost.

That’s nearly twice as much as is currently contained in the atmosphere.

Estimates have suggested as much as 40 percent of Arctic permafrost could be lost if, as predicted, global average temperatures rise to 3.6F above pre-industrial levels by 2100.

Experts have warned that humanity must drastically cut its greenhouse gas emissions by 2044 in order to avoid a “tipping point” that would see permafrost lost at an unprecedented rate.