'Death by global warming'

Scientists predict that global warming could be responsible for millions of extra deaths.

Although coroners will not write it officially on a death certificate, these scientists predict global warming will be the ultimate cause of death as people succumb to disease in an increasingly unhealthy environment.

We are getting into an unfamiliar and hazardous world

Professor Tony McMichael

David Pimentel, a professor in ecology at Cornell University in America, said global warming would create a favourable climate for disease-causing organisms and food-plant pests.

He told the annual meeting of the American Association for the Advancement of Science (AAAS) in Washington: "Right now the evidence of significant global climate change is minimal, but there are already noticeable increases in human diseases worldwide."

Marginal change

His comments were echoed by Tony McMichael, professor of epidemiology at the London School of Hygiene and Tropical Medicine.

Malaria epidemics could increase due to global warming

He said: "Global warming has already caused a marginal change in the last decade.

"We are getting into an unfamiliar and hazardous world."

Professor McMichael said diseases that breed in warm and wet conditions were likely to become more prevalent in the next 20 years.

There was the potential for disease epidemics such as malaria and Dengue fever - and rates of diarrhoea and food poisoning were also likely to rise dramatically.

Surveillance systems

Professor McMichael said action had to be taken now in a bid slow down global warming.

Global warming will only make matters worse

Professor David Pimentel

He said research into how global climates affect human diseases should be made a priority.

And more surveillance systems, which aim to help combat future problems, should be set up.

Surveillance systems have recently been set up in Africa and have meant preventative measures, such as public health defences including vaccinations and mosquito nets, could be given out ahead of a predicted disease outbreak.

Familiar hype

There will be some scientists who will recognise what they regard as the familiar global warming hype in the ecologists' comments

There is a sizeable group of researchers who do not accept that the Earth is going through a period of dramatic warming

They point to the inconsistencies in the temperature records over the last century, and in particular the data measured from space which shows no warming trend in recent times at all.

These scientists are also critical of the computer models which are used to project future climate change arguing that they are based on poorly understood phenomena such as cloud formation and the movement of heat through the oceans - complex processes that cannot be satisfactorily reproduced by current technology.

They regard the sort of concern expressed at the AAAS meeting to be unnecessarily dramatic.