Discussions of climate usually focus on power plants, cars and forests. Microbes rarely make the list, yet single-celled organisms are central to the planet's chemistry. They produce and consume methane, cycle nitrogen, generate oxygen and influence how much carbon is stored in soil and ocean. A collection of field reports makes the case for taking them seriously.
The dispatches come from very different environments: rice paddies, thawing permafrost, deep-sea sediments and the guts of ruminants. In each setting, microbial communities determine whether carbon is locked away or released, and in what chemical form. Some of the processes are fast and responsive; others unfold over centuries, making them difficult to measure but impossible to ignore.
The reports also describe how researchers propose to work with these organisms rather than against them. Targeted interventions in agriculture, wetlands and waste treatment could reduce emissions at modest cost, provided the underlying microbiology is understood well enough to avoid unintended consequences. It is unglamorous work with global stakes.
