In the past thirty years the number of deaths resulting from extreme heat in Stockholm, Sweden, was double that which would be expected without climate change, according to a paper published online this week in Nature Climate Change.

Daniel Oudin Astrom and colleagues investigate whether extreme temperature-related mortality during 1980-2009 can be attributed to effects of climate change that have occurred since the 1900-1929 reference period. They find that mortality was significantly elevated because of the increased frequency of hot weather events since the beginning of the twentieth century, and there is little evidence that the population had adapted to deal with these changes. The frequency of cold extremes also increased slightly, despite higher average winter temperatures, contributing to a small rise in mortality during the winter months.