The upside to global warming might be milder winters. This would naturally lead to fewer deaths to due cold but an analysis of data from the past 60 years shows that is not likely.

Researchers from the University of Exeter and University College London set out to debunk the widely held view that warmer winters will cut the number of deaths normally seen at the coldest time of year. They looked at how the winter death rate has changed over time, and what factors influenced it and found that from 1951 to 1971, the number of cold winter days was strongly linked to death rates, while from 1971 to 1991, both the number of cold days and flu activity were responsible for increased death rates. However, their analysis showed that from 1991 to 2011, flu activity alone was the main cause in year to year variation in winter mortality.

"We've shown that the number of cold days in a winter no longer explains its number of excess deaths. Instead, the main cause of year to year variation in winter mortality in recent decades has been flu," said lead researcher Dr Philip Staddon.  

They instead say that this reduced link between the number of cold days and deaths in a winter can be explained by improvements in housing, health care, income and a greater awareness of the risks of the cold.

If climate change progresses, the UK might experience increasing weather extremes, including a greater number of less predictable periods of extreme cold. 

Staddon says, "Both policy makers and health professionals have, for some time, assumed that a potential benefit from climate change will be a reduction in deaths seen over winter. We've shown that this is unlikely to be the case. Efforts to combat winter mortality due to cold spells should not be lessened, and those against flu and flu-like illnesses should also be maintained."

Published in Nature Climate Change.