This session is in accordance with the emphasis of the 95th ESA conference on the past and future of global warming. Numerous greenhouse gases are both created and consumed by microorganisms within the soil. There are a wide variety of microorganisms which mediate these transformations, about which we are only just beginning to learn. This emerging field benefits from both the collection of new data on these microorganisms and the synthesis of previously published data to ask new questions. This field would not be in the forefront that it is today if previous generations of scientists had not called the public’s attention to the increasing threat of global warming. Now the nation and the world are listening to what scientists find on the matter, and there is much to be learned from the microorganisms on this topic. The speakers in this session do either in situ, laboratory or synthesis research on soil microbially-mediated gas fluxes relevant to global warming, with particular emphasis on the effects of environmental variability on the fluxes of methane and nitrogenous gases.