By Alister Doyle, Environment Correspondent
OSLO, Feb 23 (Reuters) - 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 showed on Sunday.
A draft U.N. 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 would likely not decrease 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 told Reuters that the findings were likely to apply to other developed countries in temperate regions that risk more extreme weather as temperatures rise.
Excess winter deaths (EWDs), 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 2012-12 from 60,000 typical in the 1950s, official data show.
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. "The correlation between the number of cold winter days per year and EWDs, which was strong until the mid-1970s, no longer exists."
Staddon's findings are at odds with a 2012 Climate Change Risk Assessment by the British Department for Environment, Food and Rural Affairs (Defra) that said global warming would bring "some potential benefits, for example, a projected reduction in winter mortality."
Asked to comment on Sunday's report, a Defra spokesman said an updated climate assessment was due in 2017.
"We will continue to take account of the latest scientific evidence," he said.
Many governments are reviewing health spending priorities and summer heatwaves are often seen as a bigger threat than winter cold. U.N. studies say it is at least 95 percent probable that most warming in recent years is man-made.
Staddon said developed nations should avoid a radical shift in spending to heatwave protection, such as better air conditioning in homes for the elderly, from measures to ease cold such as subsidies for insulation or winter heating.
"Heatwave deaths will increase a lot but there will still be more winter deaths," he said. In 2003, the worst European heatwave in centuries killed up to 70,000 people, including about 3,000 in Britain.
Report available at: http://www.nature.com/doifinder/10.1038/nclimate2121 (Editing by Sonya Hepinstall)