Skip to main content

Sign up for our newsletter.

Quality journalism. Progressive values. Direct to your inbox.

Heated and control plots in a long-term soil warming study at Harvard Forest, Petersham, Mass. Jerry Melillo of the Marine Biological Laboratory and colleagues began the study in 1991. (Credit: Audrey Barker-Plotkin)

Heated and control plots in a long-term soil warming study at Harvard Forest, Petersham, Mass. Jerry Melillo of the Marine Biological Laboratory and colleagues began the study in 1991. (Credit: Audrey Barker-Plotkin)

Warming Soils Could Trigger Potentially Unstoppable Climate Feedback Loop: Study

Increased temperatures led to microbial activity that led to surges of carbon emissions

Andrea Germanos

New results from a long-term study point towards a potentially unstoppable feedback loop as earth's rising temperatures drive soils to release more carbon emissions.

As Bloomberg put it, "There's a carbon bomb right under your feet."

Researchers behind the 26-year, ongoing experiment buried cables in a set of plots in a Massachusetts forest and warmed the soil to 5 degrees C (9 degrees F) above the ambient temperature to see how their carbon emissions varied with those of control plots. The researchers found four phases of alternating soil carbon loss and carbon stability. Newsweek explains that "the team believes that during the peak periods, microbes [in the soil] are using up a plentiful supply of food. But when that runs out, the community has to find a new source of food, leading to the lulls in carbon release."

Over the course of the whole experiment, they found the warmed plots had lost 17 percent of the carbon that had been stored in organic matter in the top 60 centimeters (24 inches) of soil.

"To put this in context," stated lead author Jerry Melillo, distinguished scientist at the Marine Biological Laboratory in Woods Hole, Mass., "each year, mostly from fossil fuel burning, we are releasing about 10 billion metric tons of carbon into the atmosphere. That's what's causing the increase in atmospheric carbon dioxide concentration and global warming."

"The world's soils contain about 3,500 billion metric tons of carbon," he continued. "If a significant amount of that soil carbon 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. There is no switch to flip."

If the same kind of carbon release measured at the New England site occurred across the globe, over the course of the century it would be the "equivalent to the past two decades of carbon emissions from fossil fuel burning," the researchers extrapolate.

"The future is a warmer future. How much warmer is the issue," Melillo said, noting that actions like shutting down coal plants can help reign in carbon emissions from fossil fuels. "But if the microbes in all landscapes respond to warming in the same way as we've observed in mid-latitude forest soils, this self-reinforcing feedback phenomenon will go on for a while and we are not going to be able to turn those microbes off.  Of special concern is the big pool of easily decomposed carbon that is frozen in Artic soils. As those soils thaw out," he continued, "this feedback phenomenon would be an important component of the climate system, with climate change feeding itself in a warming world."

As Melillo's study, published Friday in the journal Science, adds to research finding warming leads to soils releasing, rather than sequestering, carbon, separate research is also showing how soil, with better land management practices, can help mitigate climate change.

"Dirt," said Rob Jackson, who lead the research published in the Annual Review of Ecology, Evolution and Systematics, "is a no-risk climate solution with big co-benefits. Fostering soil health protects food security and builds resilience to droughts, floods, and urbanization."


Our work is licensed under Creative Commons (CC BY-NC-ND 3.0). Feel free to republish and share widely.

This is the world we live in. This is the world we cover.

Because of people like you, another world is possible. There are many battles to be won, but we will battle them together—all of us. Common Dreams is not your normal news site. We don't survive on clicks. We don't want advertising dollars. We want the world to be a better place. But we can't do it alone. It doesn't work that way. We need you. If you can help today—because every gift of every size matters—please do. Without Your Support We Simply Don't Exist.

Border Patrol Accused of 'Unfathomable Cruelty' for Cracking Whips on Haitians

"It doesn't matter if a Democrat or Republican is president, our immigration system is designed for cruelty towards and dehumanization of immigrants," said Rep. Alexandria Ocasio-Cortez.

Brett Wilkins ·


As Gov. Tim Walz Proclaims 'Minnesota Climate Week,' Ilhan Omar Says 'Stop Line 3'

"The state of Minnesota simply cannot meet our carbon reduction targets if this pipeline goes through," said the Democratic congresswoman. "Our future is on the line."

Kenny Stancil ·


Supreme Court Announces Date for Case Directly Challenging Roe v. Wade

"The fate of Roe v. Wade and legal abortion is on the line."

Julia Conley ·


Avi Lewis Hoping Canadians' Climate Concerns Deliver Electoral 'Upset of Epic Proportions'

"We need to send Avi to Ottawa to shake up the entire political establishment, including his own party, and tip the scales in favor of people and the planet," said environmentalist David Suzuki.

Brett Wilkins ·


Sanders Denounces a Pentagon Budget System Found 'Inherently Susceptible to Fraud'

"They don't seem to want to get serious about spending taxpayer dollars wisely and effectively," said the Vermont senator, declaring it "absolutely unacceptable."

Andrea Germanos ·

Support our work.

We are independent, non-profit, advertising-free and 100% reader supported.

Subscribe to our newsletter.

Quality journalism. Progressive values.
Direct to your inbox.

Subscribe to our Newsletter.


Common Dreams, Inc. Founded 1997. Registered 501(c3) Non-Profit | Privacy Policy
Common Dreams Logo