In the opening presentation of the Wessex Applied Microbiologists’ symposium on Global environmental change: microbes and the environment, A.J. McMichaci (London School of Hygiene and Tropical Medicine, UK) gave a disturbing overview of environmental change and anticipated the possible impacts on health. Environmental change affects microorganisms profoundly, for example algal blooms are influenced by climate, increased nitrate levels and changes in the food chain. including overfishing. The pneumonic plague outbreak in India appears to have been associated with local climatic anomalies. Epidemics of dengue fever in Central and South America have occurred as a result of deforestation and demographic changes and it has been speculated that a 25% increase in summer food poisoning could occur by the middle of the next century.