Global warming will fail to reduce high winter death rates as some officials have predicted because there will be more harmful weather extremes even as it gets less cold, a British study shows.
A draft UN report due for publication next month says that, overall, climate change will harm human health, but adds: "Positive effects will include modest improvements in cold-related mortality and morbidity in some areas due to fewer cold extremes, shifts in food production and reduced capacity of disease-carrying vectors."
However a report in the journal Nature Climate Change on the situation in England and Wales said climate warming was not likely to cut winter mortality in those places. It suggested more volatile winters, with swings from cold to mild linked to rising greenhouse gas emissions, might even raise death rates.
Lead author Philip Staddon of the University of Exeter said that the findings were likely to apply to other developed countries in temperate regions that risked more extreme weather as temperatures rose.
Excess winter deaths, the number of people who die in winter compared to other times of the year, roughly halved to 31,000 in England and Wales in 2012-13 from 60,000 typical in the 1950s. Staddon's report said the decline was due to better home insulation, heating, health care and other non-climate factors with no link to a decline in the number of cold days.
"Winter cold severity no longer predicts the numbers affected," the authors wrote.
Staddon's findings are at odds with a 2012 Climate Change Risk Assessment by the British Department for Environment, Food and Rural Affairs that said global warming would bring "some potential benefits, for example, a projected reduction in winter mortality".