Carbon escaping from soils could accelerate global warming

The world's soils contain huge amounts of carbon, and global warming causes much of the carbon to escape as carbon dioxide, according to a new study. The study authors warn that the released carbon dioxide inevitably creates even more global warming, in a destructive feedback loop.
By Lucas Rowe | Oct 06, 2017
As the planet warms, soils release more carbon dioxide, which in turn leads to even more global warming, according to a 26-year study published Friday in the journal Science. The authorswho include researchers from the U.S. Marine Biological Research Laboratory and the universities of New Hampshire and Massachusetts, foresee a destructive feedback loop that could escalate to the point of becoming unstoppable.

The world's soils contain around 3,500 billion tons of carbon, which stays stored in organic matter, according to Jerry Mellilo, a U.S. Marine Biological Research Laboratory. He explained that bacteria live in the soils and feed on the matter while releasing carbon dioxide as a byproduct.

As outside temperatures warm, he said, bacteria digest matter more quickly, he addedand as more carbon dioxide escapes, which may contribute to even more warming.

"If a significant amount of that (carbon) is added to the atmosphere, due to microbial activity, that will accelerate the global warming process. Once this self-reinforcing feedback begins, there is no easy way to turn it off. There is no switch to flip," he said.

Researchers have long known about this carbon and its potential to enter the atmosphere. But this recent study determined that the carbon release is occurring at a much greater scale than researchers had expected, which they worry will hasten global warming.

Melillo and colleagues based their study on observations of soil plots in Massachusetts' Harvard Forest. They heated some soil areas and left others alone to serve as controls. The researchers found strong increases in carbon-dioxide emissions, lasting years at a time, from the heated soils.


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