Climate experts issued their starkest warning yet about the impact of global warming, ranging from hunger in Africa to a fast thaw in the Himalayas, in a report yesterday that increased pressure on governments to act.

More than 100 nations in the UN climate panel agreed a final text after all-night talks during which some scientists accused governments of watering down conclusions that climate change was already under way and damaging nature.

The report said warming, widely blamed on human emissions of greenhouse gases from burning fossil fuels, would cause desertification, droughts and rising seas and would hit hard in the tropics, from sub-Saharan Africa to Pacific islands.

The Intergovernmental Panel on Climate Change (IPCC), which groups 2,500 scientists and is the world authority on climate change, said all regions of the planet would suffer from a sharp warming.

Its findings are approved unanimously by governments and will guide policy on issues such as extending the UN's Kyoto Protocol, the main UN plan for capping greenhouse gas emissions, beyond 2012.

In Washington, the Bush administration indicated the US, which pulled out of Kyoto in 2001, still planned to tackle limiting carbon dioxide emissions on its own rather than support global mandatory caps.

"Each nation sort of defines their regulatory objectives in different ways to achieve the greenhouse reduction outcome that they seek,"Jim Connaughton, chairman of the White House council on environmental quality, told reporters.

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