Global warming is likely to cause a decline in the number of species of microbes that live in tropical soils which could threaten the biodiversity of rainforests and increase carbon emissions, according to new research. Microorganisms, which include bacteria and fungi, play a key role in the health of tropical forest ecosystems. They breakdown dead organic matter, and use, transform or release as CO2. About a third of the carbon stored in soils is held in tropical soils—and they support around two-thirds of the world’s plant biomass. Climate models suggest the tropics could warm by two to five degrees centigrade by the end of the century. To date, there has been little scientific research into the impact this level of warming could have on the tropical soil microbes that play a key role in plant health and in mediating carbon emissions.