WHO Director General Dr Margaret Chan said yesterday, 7th April 2008, World Health Day, that climate change was already affecting human health and was giving "a glimpse of the challenges public health will have to confront on a large scale".

Chan said the scientific evidence that the planet is warming is "unequivocal": average air and sea temperatures are rising, ice caps are melting, and sea levels are increasing. This should help us understand and prepare for coming challenges she said, at the heart of which is the main concern:

"Climate change endangers human health," said Chan.

In the UK There are a number of steps the NHS can take to help address climate change, according to the British Medical Association (BMA).

The doctors' group has warned that factors associated with climate change – frequent floods, heatwaves and other extreme weather conditions – could have huge health impacts for the UK.

Its report, Health Professionals – Taking Action on Climate Change, says health professionals should take the lead on this issue.

The BMA argues that doctors have the opportunity and responsibility to highlight the public health risks associated with climate change.

This has been reiterated in guidance issued by the Department of Health, which says health workers throughout the country should play a part in tackling the health effects of climate change.

BMA head of science and ethics Dr Vivienne Nathanson said health professionals are in a unique position to influence and promote social change by addressing climate change.

"The NHS is the largest single organisation in the UK with an annual purchasing budget of around £17 billion. It employs over one million people and emits around one million tonnes of carbon every year," she added.

"There is huge potential for this employer to promote combating climate change. It is essential that when new hospitals, GP surgeries and other premises are being built that we learn from best-practice construction projects."