Increase in overheating deaths not offset by reduction in winter mortality in Sweden

In the 30 years since 1980, climate change doubled the number of heat-related deaths in Stockholm.

This is the recent finding of a team of Swedish scientists looking at mortality data in Stockholm, and comparing them to mortality data from 1900–1929. In 2003, 207, 200, and 2012 the northern hemisphere saw unprecedented heat extremes in summertime, and 2010 temperatures exceeded all 20th and 21st century records.

By calculating the weeks where people were most at risk (from heat or cold), and considering the age groups most vulnerable to these extremes, the team compared mortality patterns over these two periods and observed that 31 extra cold spells (250 in the last 30 years versus 220 in 1900–1929) accounted for 75% of premature deaths. Extreme heat was more dramatically deadly: 220 very hot spells in the early part of the century compared to 381 heat extremes in the last 30 years. These additional hot periods led to an extra 288 heat-related deaths in Stockholm. What’s more, climate change appears to be the culprit, with a 95% probability; without the changes made since the start of the century (increased life expectancy, better health care, cars, street lights, higher air temperatures in cities), the team figure the additional heat-related deaths would be nearly double the number from the pre-warming period.