Global warming poses a growing threat to the health, economic prospects, and food and water sources of billions of people, top scientists said in a report that urges swift action.

The latest report from the UN Intergovernmental Panel on Climate Change (IPCC) says the effects of warming are being felt everywhere, fuelling potential food shortages, natural disasters and raising the risk of wars. “The world, in many cases, is ill-prepared for risks from a changing climate,” the IPCC said yesterday, after the final text of the report was agreed.

More warming increased the chance of harsh, widespread impacts that could be surprising or irreversible, it added. The report projects global warming may cut world economic output by between 0.2 and 2.0 per cent a year should mean temperatures rise by 2 degrees Celsius.

“Over the coming decades, climate change will have mostly negative impacts,” said Michel Jarraud, Secretary-General of the World Meteorological Organisation (WMO), citing cities, ecosystems and water supply as being among the areas at risk.

“The poor and vulnerable will be most affected,” he added. It emphasises the risks and portrays cuts to greenhouse gas emissions as an insurance policy for the planet. The risks range from death to disrupted livelihoods in coastal zones and small islands, due to storm surges, coastal flooding, and sea-level rise, the report said.