A remarkable new study published in the journal Science indicates that carbon emissions from warming soils could be a lot higher than we previously thought, and it could result in a chain of events that would greatly intensify global warming. Researchers found that there was a major uptick in carbon production in microbes found within soil at the Harvard Forest in Massachusetts.

Scientists used underground cables to heat some of the soil plots in the forest, raising the temperature by about 40 degrees Fahrenheit, while unheated plots were set aside as control for the experiment. After about 10 years, scientists measured again and found that carbon emissions from heated soil had greatly increased. After a seven year period where emissions declined again, the carbon emissions went on an upward trajectory once again for six more years.

In the final three years of the study, the carbon emissions from the soil went down again. Both times there was a decline in emissions, scientists think that the microbes were simply adjusting to the new temperatures, and as a result they think that it is just the calm before the storm, as it were. The 26-year study is the biggest of its kind and could result in breakthroughs in how we study and understand global warming and climate change.

The full statement from the Marine Biological Laboratory follows below.

After 26 years, the world’s longest-running experiment to discover how warming temperatures affect forest soils has revealed a surprising, cyclical response: Soil warming stimulates periods of abundant carbon release from the soil to the atmosphere alternating with periods of no detectable loss in soil carbon stores. Overall, the results indicate that in a warming world, a self-reinforcing and perhaps uncontrollable carbon feedback will occur between forest soils and the climate system, adding to the build-up of atmospheric carbon dioxide caused by burning fossil fuels and accelerating global warming. The study, led by Jerry Melillo, Distinguished Scientist at the Marine Biological Laboratory (MBL), appears in the October 6 issue of Science.