text: Compared with the likely benefits to both human health and food production from CO2-induced global warming, the possible disadvantages from, say, a slight increase in either the frequency or the intensity of extreme weather events is very small beer. It is, in fact, still uncertain whether there is any impact on extreme weather events as a result of warming (increased carbon emissions, which have certainly occurred, cannot on their own affect the weather: it is only warming which might). The unusual persistence of heavy rainfall over the UK during February, which led to considerable flooding, is believed by the scientists to have been caused by the wayward behaviour of the jetstream; and there is no credible scientific theory that links this behaviour to the fact that the earth's surface is some 0.8C warmer than it was 150 years ago.