By Chris Buckley BEIJING, Nov 10 (Reuters) - Deadly heatwaves, hurricanes and spreading malaria infections appear to be just the obvious toll of global warming on people's health, said a scientist leading efforts to unravel how environmental change threatens lives. "The thing that excites our governments most, and the public, is the prospect of climate change doing damage to the economic system," Tony McMichael, a professor at Australia's National University, said in Beijing on Friday. "But much worse, of course, in terms of real sustainability is damage to the life-support system." Last week, the British government issued a report warning that global warming, driven by man-made emissions of greenhouse gases that keep heat in the atmosphere, could devastate global growth, plunging the world into an economic crisis on a par with the 1930s Depression. Now scientists are trying to understand how environmental change may also do more elusive harm to health by spreading less well-known diseases, drying up water, raising sea levels, and displacing people in waves of environmental refugees, McMichael said. "Most of the answers are not simple," he said. "They don't reduce to simple causal diagrams." McMichael was in Beijing to attend the launch of a new international effort to study global environmental change and health. A report for the programme offered some clues of the scale of potential havoc. It said that 3 billion people may be threatened by Dengue fever because of climate change and urbanisation, 40 percent of the world's population may be threatened by malaria, and malnutrition due to climate change and loss of land and water could put 840 million at risk. "Global climate change will have diverse, escalating impacts on human health," said the report. Even if countries agreed to immediately cut emissions of greenhouse gases, changes in climate -- and disease -- will be unavoidable due to current greenhouse gas levels, it said. McMichael is helping vet the next report of the Intergovernmental Panel on Climate Change, the United Nations group that assesses research on global warming and its effects. The report is due out early next year. But the new scientific effort announced in Beijing will look beyond global warming to examine how other environmental hazards may damage health. Loss of forests and natural diversity, urbanisation, and the spread of warm-climate species and diseases into once-cool climates may all badly damage human health, scientists at the launch said. The connections between these changes are too complex to be treated in isolation from each other, said McMichael.
