Stanford scientists forced bacteria into oxygen-starved (anaerobic) environments where they produced far less CO2, according to their study released today in the journal Nature Communications. In this mode, the bacteria decomposed far fewer carbon-rich lipid and wax molecules, which dropped carbon dioxide production by a factor of 10.

Of course, the model could shift the other way: If previously oxygen-deprived bacteria is exposed (say, if rigorous farming disrupts the soil), they could increase by tenfold the amount of CO2 they put into the atmosphere. Similarly, warming climate -- or different irrigation patterns as humans adjust to changing weather -- could accelerate soil bacteria's carbon dioxide production.