From the first molecules of oxygen produced by marine cyanobacteria ~3.5 billion years ago to the methanogens luxuriating in the warm, carbon-rich swamps of the Carboniferous period, microbial processes have long been key drivers of, and responders to, climate change. It is widely accepted that microorganisms have played a key part in determining the atmospheric concentrations of greenhouse gases, including carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) (which have the greatest impact on radiative forcing), throughout much of Earth’s history. What is more open to debate is the part that they will play in the coming decades and centuries, the climate feedbacks that will be important, and how humankind might harness microbial processes to manage climate change. The feedback responses of microorganisms to climate change in terms of greenhouse gas flux may either amplify (positive feedback) or reduce (negative feedback) the rate of climate change. With the twenty-first century projected to experience some of the most rapid climatic changes in our planet’s history, and with biogenic fluxes of the main anthropogenic greenhouse gases being tied integrally to microorganisms, improving our understanding of microbial processes has never been so important.
Microorganisms and climate change: terrestrial feedbacks and mitigation options. (2010) Nature Reviews Microbiology 8, 779 doi:10.1038/nrmicro2439
Microbial processes have a central role in the global fluxes of the key biogenic greenhouse gases (carbon dioxide, methane and nitrous oxide) and are likely to respond rapidly to climate change. Whether changes in microbial processes lead to a net positive or negative feedback for greenhouse gas emissions is unclear. To improve the prediction of climate models, it is important to understand the mechanisms by which microorganisms regulate terrestrial greenhouse gas flux. This involves consideration of the complex interactions that occur between microorganisms and other biotic and abiotic factors. The potential to mitigate climate change by reducing greenhouse gas emissions through managing terrestrial microbial processes is a tantalizing prospect for the future.