Weatherwatch

As much of the UK swelters this week, it seems that our attitude to such weather is likely to change. New estimates show that by 2080 around 500 Londoners will die of heat-related causes every year. And London is not the only city with a problem. From Lisbon to Boston and Budapest to Sydney, extreme temperatures are likely to be a major killer by the end of the century.

Currently an average of 120 people die from heat-related problems in London every summer. This was predicted to rise to around 250 people by 2080, but now the latest estimates show it is likely to be over 500. Simon Gosling, from the University of Reading, and his colleagues investigated heat-related mortality in six cities - Boston, Budapest, Dallas, Lisbon, London and Sydney. Crucially they looked at temperature variability as well as the average increase in temperature. Projections from a recent Met Office climate model show large swings in day to day temperatures in the future, with many more exceedingly hot summer days than we experience now. Even mild and unexceptional summers will have days where the mercury rises to dangerous levels. When applying this to people's health Gosling and his colleagues show that heat-related mortality will rise sharply for London, Boston and Budapest. In very hot cities like Dallas the effect is less pronounced - temperatures are fairly extreme there for much of the time already.