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The heat-trapping gases humans release into the air are warming the planet. But humble soil-dwelling bacteria and fungi also release heat-trapping gases, and those gases could determine just how hot it gets. Now new research adds to the worry that the microbes will make climate change worse.

Soil microbes digest dead plants and animals. And, like us, they "breathe out" carbon dioxide. Some scientists predict that as temperatures rise, bacteria and fungi will speed up their metabolisms, spewing vast stores of carbon from the soil into the atmosphere. Others think heat could slow soil microbes down, heading off this potential carbon burp.

A team of scientists has now taken an important step toward lowering the uncertainty about the microbes' likely response. The researchers conducted the first tropical soil carbon warming experiment by carting tubes of soil up and down a mountainside and measuring how the soil’s carbon content changed. The research suggests a huge carbon bomb may be waiting to explode, the team said, possibly boosting carbon dioxide in the atmosphere by almost 10% over a century -- an amount that would have severe impacts on life on the planet. 

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