There’s a lot scientists don’t know about how global warming could impact Earth’s natural systems. Now, a 26-year-study of soil in Massachusetts’ Harvard Forest provides new insight. Researchers discovered warming soils are releasing more carbon than once thought – which could lead to uncontrollable temperature rise.


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The scientists started the Harvard Forest experiments back in 1991. They scrutinized plots of soil, heating some to five degrees Celsius higher than normal levels with underground cables. Microbes played a role in the greater production of carbon. In the first 10 years, the scientists saw a spike in the carbon the heated plots released, and then there was a seven-year period when the release lessened – scientists think soil microbes were adjusting to the warmer conditions. But then the release of carbon increased again. The past three years has seen carbon release slow again, with researchers thinking microbes might be reorganizing.

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The heated plots lost around 17 percent of the carbon stored in the soil’s top 60 centimeters. Study lead author Jerry Melillo, of the Marine Biological Laboratory in Massachusetts, said in a statement, “Each year, mostly from fossil fuel burning, we are releasing about 10 billion metric tons of carbon into the atmosphere…The world’s soils contain about 3,500 billion tons of carbon. If a significant amount of that is added to the atmosphere, due to microbial activity in warmer soils, that will accelerate the global warming process. And once this self-reinforcing feedback begins, there is no easy way to turn it off.”

Daniel Meltcalfe of Lund University, who was not a part of the study, told The Guardian if the findings hold across other terrestrial ecosystems, a larger amount of soil carbon might be vulnerable to decomposition than we thought.

The journal Science published the study today. Scientists from institutions in Massachusetts and New Hampshire contributed to the research.

Via The Guardian

Images via Daniel Spiess on Flickr (1,2)