Deaths caused by heat will rise to average of 7,000 a year in 2050

However milder winters will mean fewer cold-related deaths

Rising temperatures and an increasing elderly population will mean that more people die (Getty Images)

The number of deaths caused by extreme heat in the UK will more than treble by the middle of the century as a result of climate change and population growth, experts have said.

Rising temperatures and an increase in the size of the elderly population will mean that more than 7,000 people will die because of the heat in an average year in the 2050s – compared to just 2,000 today.

However, milder winters will mean that a smaller proportion of people will die from the effects of the cold.

The study, published in the British Medical Journal on Tuesday, used historic data on the link between temperature fluctuations and death rates. The authors then applied these associations to projected temperature changes as predicted by the British Atmospheric Data Centre and population growth estimates from the Office for National Statistics.

Days in which the average mean temperature exceeds 20 degrees Celsius will likely treble by the 2050s, said lead author Dr Shakoor Hajat of the London School of Hygiene and Tropical Medicine (LSHTM), with more than four times as many such days by the 2080s. The population is projected to increase to 89 million by 2080 – by which time over 85s will represent nine per cent of the population, compared to two per cent today.

Regional variations in temperature are likely to persist, with people in London and the Midlands most vulnerable to hot weather, according to the study, which was co-authored by experts working with the Government agency Public Health England.

“A lot of these deaths, both heat-related and cold-related, are occurring in people who are very infirm – mainly elderly people with underlying health problems,” Dr Hajat said. “Even if mean temperatures go over 20C we start seeing some heat-related deaths – usually from cardiovascular and respiratory problems.

“As the world warms up it’s likely that populations will adapt to some extent, however because of the increased variability [in the weather] that we’re expecting and the rate of change in the warming, it’s unclear how successful future adaptations will be.”

Much of the increase in the number of deaths can be attributed to increases in population size and age, and any increases in heat-related deaths caused by climate change will likely be more than offset by decreases in the proportion of people dying during milder winters.

If the population were to remain the same, but temperatures continue to rise as predicted, there would be 3,000 more heat-related deaths in 2050 compared to today, but 10,000 fewer people dying as a result of cold weather, Dr Hajat said.

However, he added that the increased risk in the warmer months would require the people to adapt their behaviour, always ensuring they remained hydrated by taking in water even when they weren’t thirsty.

“We’re also likely to see air conditioning prevalence increase in the UK, but inequalities may mean those most at risk may not be able to afford these unless they are subsidised by the Government and rising fuel costs may exacerbate this discrepancy,” he said.