That is the conclusion of a major new report from the UK's Health Protection Agency, which warns that while rising temperatures this decade will lead to a modest reduction in deaths related to cold weather, any gains will be more than offset by a huge increase in heat-related deaths during the second half of the century.
A further increase in premature deaths and hospital admissions is also predicted as a result of increased ozone pollution in city centres, resulting from higher summer temperatures, with the report predicting annual ozone-related deaths could increase from 11,900 currently to between 14,000 and 15,000 by the 2030s.
Equally worrying are projections that changing climatic patterns could leave the UK vulnerable to new disease vectors if, as some scientists expect, mosquitos establish themselves more widely in the UK.
Moreover, the report indicates that businesses could face significant disruption as a result of climate-related health impacts, warning that "climate change may exacerbate health risks associated with building overheating, indoor air pollution, flood damage and water and biological contamination of buildings".
Dr David Heymann, chairman of the Health Protection Agency, urged policy-makers to take action to address the threats revealed by the report.
"From increased risks of heatwaves through to potentially greater exposure to air pollution, indoors and outdoors, and potential changes to established pollen seasons, there are many issues all of which need further research and attention if we are to adapt to, or mitigate the effects," he said in a statement.
"We are confident that this report will provide all government departments with the further information they need to properly prioritise areas for future work and protect the UK public from the significant looming health challenges that climate change presents."
Professor Dame Sally Davies, chief medical officer at the Department of Health, argued that there was now ample evidence that low-carbon technologies and policies would deliver a substantial dividend in terms of public health.
"As well as preparing for the health impacts of climate change, we are also able to help prevent the worst of these impacts as urgent action to reduce individual and corporate carbon footprints continues," she said. "We can then also reap the health benefits of a low-carbon society, with cleaner air and more active, healthier lifestyles to help combat obesity, cancer and heart disease. A win-win we can all engage in."
The report is expected to inform ongoing work by the Department of Environment, Food and Rural Affairs to develop the UK's first national climate change adaptation strategy, which is expected to be released early next year.