The risk of a fatal heatwave in the UK within ten years is high, but overall global warming may mean fewer deaths due to temperature, a report says.
Heatwaves: fun for some, deadly for others
A seriously hot summer between now and 2017 could claim more than 6,000 lives, the Department of Health report warns.
But it also stresses that milder winters mean deaths during this time of year - which far outstrip heat-related mortality - will continue to decline.
The report is to help health services prepare for climate change effects.
A panel of scientific experts commissioned by the Department of Health and Health Protection Agency (HPA) has looked at the way the UK has responded to rising temperatures since the 1970s, and how the risks are likely to change.
While summers in the UK became warmer in the period 1971 - 2003, there was no change in heat-related deaths, but annual cold-related mortality fell by 3% as winters became milder - so overall fewer people died as a result of extreme temperatures.
Rather than physiological changes explaining our ability to adapt to rising temperatures, the report puts this down primarily to lifestyle alterations - our readiness to wear more informal clothes, for instance, and the shift away from manual labour.
Nevertheless, there is at present a 25% chance that by 2017 south-east England will see a severe heatwave which could cause 3,000 immediate deaths and the same number of heat-related deaths throughout the summer.
Have a fan
Keep windows open as long as cooler outside
Invest in blinds
Eat regularly, and keep salt levels up
While the authors acknowledge that predicting heatwaves and their effects is difficult, the risk was nonetheless "high".
However, even 6,000 deaths pales in comparison with the number of cold-related deaths, which in the UK currently average about 20,000 per year.
It is also a mixed picture when it comes to the health impact of air pollution.
As a result of regulations, levels of several key pollutants are likely to decline over the next 50 years, but the concentration of ozone may well increase.
This is associated with breathing difficulties, particularly for asthmatics and those with existing lung problems, and could lead to 1,500 extra hospital admissions and deaths every year.
Skin cancer meanwhile is also likely to increase, although there are studies which suggest greater exposure to sunlight may prevent other forms of cancer.
Other areas which had caused concern may transpire not to be as worrying as initially thought.
A reappraisal of the evidence suggests malaria outbreaks are likely to remain rare, although health authorities need to be alert to outbreaks in continental Europe which could affect travellers, the report says.
However, while vector-borne diseases may not be the problem once thought, food-borne ones remain an issue: improved food hygiene will be necessary to prevent a 14.5% increase in food poisoning by bacteria such as Salmonella, which is affected by rising temperature.
More work ahead
Sudden periods of heavy rain may well increase the risk of flooding in some places although certain types of flooding - notably those linked to melting snow - may become less common.
While flooding is traumatic for those affected, it causes few direct deaths. Relatively little is known about the total health effects of a flood, and more work is needed, the report adds.
However heavy rain over a short period can certainly increase the amount of bacteria in surface drinking water, while increasing temperatures may stop current disinfection methods from working properly - a challenge which needs to be addressed.
"Climate change poses great challenges and it is important to plan ahead for the health consequences," said Public Health Minister Dawn Primarolo.
"Let's not forget we also have a societal role to play in the mitigation of climate change by supporting sustainable development programmes - through consumer choice, reducing our carbon footprints and recycling waste."
Gill Morgan, head of the NHS Federation, said the country's health service "has a major role to play in tackling climate change".
"As the report highlights, rising temperatures will put significant pressure on the NHS, and may increase the amount of heat-related deaths and skins cancers, as well as respiratory and insect-borne diseases."