The effects of global warming have long been a focus of scientists’ attention, not only since the USA rejected the Kyoto Protocol, which was drafted to curb the emission of so‐called greenhouse gases. The potential consequences of increasing the Earth's temperature by just a few degrees include a rise in ocean levels due to melting of the polar ice caps, parching of the land and changes of storm, flood and drought patterns. These scenarios are mainly debated among climatologists, but biologists are adding a further dimension with another potentially disastrous effect. ‘In the past five years, there has been increasing discussion about global warming and its potential impact on diseases like malaria and dengue fever in the tropics and even in temperate zones’, Uriel Kitron, Professor of Epidemiology at the University of Illinois in Urbana‐Champaign, said. Indeed, many scientists point to global warming as a factor in the spread of malaria and other vector‐borne infectious diseases. This camp believes that global warming is likely to disturb a delicate equilibrium and contribute to new epidemics of malaria, yellow and dengue fever and encephalitis. Kitron has been studying the invasion of the tiger mosquito in Illinois, LaCrosse encephalitis in the Great Lakes region, and dengue and malaria in Trinidad, Kenya and Mozambique. His research, however, does not clearly link global warming with the spread of these diseases. ‘Vector‐borne diseases have an extremely complex ecology, which renders transmission and what it takes to produce disease not that simple and clear cut’, he said. > Many scientists believe that global warming is likely to disturb a delicate equilibrium and contribute to new epidemics of malaria, yellow and dengue fever and encephalitis Unlike Kitron's middle‐of‐the‐road view, much of the scientific thinking on the topic is polarised, and seems to be tinged with politics. Paul Epstein, Associate …