Causes for the recent changes in cold- and heat-related mortality in England and Wales

Cold related mortality among people aged over 50 in England and Wales has decreased at a rate of 85 deaths per million population per year over the period 1976–2005. This trend is two orders of magnitude higher than the increase in heat-related mortality observed after 1976. Long term changes in temperature-related mortality may be linked to human activity, natural climatic forcings, or to adaptation of the population to a wider range of temperatures. Here we employ optimal detection, a formal statistical methodology, to carry out an end to end attribution analysis. We find that adaptation is a major influence on changing mortality rates. We also find that adaptation has prevented a significant increase in heat-related mortality and considerably enhanced a significant decrease in cold-related mortality. Our analysis suggests that in the absence of adaptation, the human influence on climate would have been the main contributor to increases in heat-related mortality and decreases in cold-related mortality.