Climate change poses such a threat to human health that it could undermine all the gains in global development during the past 50 years, an independent international commission reports on Tuesday.
The review, led by experts on medicine and economics at University College London and published in the Lancet, says immediate action is needed to avert the direct health impacts of climate change through heatwaves, other extreme weather events and the spread of infectious diseases — and indirect effects through factors such as forced migration and crop failures.
"Climate change is a medical emergency," said Hugh Montgomery, director of the UCL Institute for Human Health and Performance, who co-chaired the commission.
"It thus demands an emergency response, using the technologies available right now.
"Under such circumstances, no doctor would consider a series of annual case discussions and aspirations adequate, yet this is exactly how the global response to climate change is proceeding."
But the authors told a press preview of the report in London on Monday that they wanted to avoid issuing another gloom and doom warning about climate change.
"Our analysis clearly shows that by tackling climate change, we can also benefit health — and tackling climate change in fact represents one of the greatest opportunities to benefit human health for generations to come," said Anthony Costello, director of the UCL Institute for Global Health.
The report lists immediate health benefits from action against climate change.
For instance walking or cycling instead of driving helps to fight obesity, heart disease and stroke, while cutting air pollution and motor vehicle accidents. Burning less coal reduces respiratory disease. Eating fewer animal products and more local fruit and vegetables would lead to a healthier diet.
The biggest direct effect of projected climate change is on heatwaves. The number of people dying from extreme heat could increase 12-fold by the end of this century, as a result of global warming combined with increasing numbers living in affected areas, said Georgina Mace, director of the UCL Centre for Biodiversity and Environment Research.
The Royal College of Physicians, which did not take part in the commission, welcomed its findings.
Jane Dacre, the college's president, said: "Doctors have always taken a wider view of health than simply treating the individual patient in front of them and this report continues that tradition, showing that for a public health issue like climate change, governments could have more influence on population health than individual patient behaviours."
Margaret Chan, director-general of the World Health Organisation, also gave the initiative her support.
"Health professionals have been at the forefront of social changes, such as those that have gradually made smoking increasingly unacceptable . . . and saving many lives," she said
The commission, which also has experts from several universities in Europe and China, plans to carry on its work through a new Climate Change and Health Action body, which will report on the health impacts of climate change and attempts to mitigate it — for instance through UN-sponsored talks culminating at a conference in Paris in December.