By Eric Roston
Soil locks away carbon just as the oceans do. But that lock is getting picked as the atmosphere warms and development accelerates.
Long before most people ever heard of climate change, scientists divided a patch of Harvard University-owned forest in central Massachusetts into 18 identical 6-meter by 6-meter squares. A canopy of red maple and black oak trees hangs there, looming above the same stony soil tilled by colonial farmers. Rich in organic material, it was exactly what the researchers were looking for.
They broke the land up into six blocks of three squares each. In every block, one square was left alone, one was threaded with heating cables that elevated its temperature 9 degrees Fahrenheit (5 degrees Celsius) above the surrounding area. The third square was threaded with cables but never turned on, as a control.
That was 26 years ago. The purpose was to measure how carbon dioxide may escape from the earth as the atmosphere warms. What they found, published yesterday in the journal Science, may mean the accelerating catastrophe of global warming has been fueled in part by warm dirt. As the Earth heats up, microbes in the soil accelerate the breakdown of organic materials and move on to others that may have once been ignored, each time releasing carbon dioxide into the atmosphere.