Arctic ‘methane bomb’ may not explode as permafrost thaws, new study suggests

Arctic permafrost with ice wedge [credit: USGS]

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Source or sink? Another supposed climate scare gets somewhat deflated by science. This time it’s the one about melting Arctic permafrost, as headlined here.
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In the Arctic, a major variable for future climate change lives in the ground, invisible – says Eos.org (via LiveScience).

Microbes in the layers of soil just above the frozen permafrost metabolize carbon, turning it into carbon dioxide and methane, a far more potent greenhouse gas. [Talkshop comment – assertion time again]

As these soils warm, more carbon is being unlocked, potentially setting in motion a warming feedback loop sometimes nicknamed the “methane bomb.”

Now, new research on the microbial denizens of Arctic soils indicates that such a vicious cycle may not be inevitable.

By cataloging the kinds of microbes found in permafrost soils from around the Arctic, as well as in recently thawed permafrost itself, a group of researchers delivered a clearer picture of microbial diversity in Arctic soils, as well as how those microbial communities change as their environment warms up.

One key finding in their paper, recently published in Communications Earth and Environment, is that under certain conditions there could be more methane-eating microbes than methane-making microbes in the Arctic, meaning the soil could actually end up being a carbon sink.

“It could be that these systems for a variety of reasons are not actually producing the methane we believe that they’re capable of producing,” said Jessica Buser-Young, a microbiologist at the University of Alaska Anchorage not affiliated with the research.
. . .
If the Arctic ends up on the dry end of the spectrum, its soils could become a net sink for methane (though not a large one) as microbes begin sucking gas from the air. The mechanism described by Urich and his colleagues is not the only potential negative methane feedback loop, either.

In a recent paper in AGU Advances, Buser-Young and her coauthors found that microbes in Alaska’s Copper River Delta that use iron for their metabolism have begun outcompeting those that produce methane, potentially reducing methane emissions.

“We believe that this could be happening potentially everywhere there’s glaciers in the world,” Buser-Young said. [Talkshop comment – sticking with ‘potentially’].

Full article here.
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Image: Arctic permafrost with ice wedge [credit: USGS]