Global warming 'already affecting world'

United Nations: Climate experts are close to agreement on the most serious UN warning yet about the impacts of global warming, and will announce that it is already having a major impact on the natural world.

The Intergovernmental Panel on Climate Change (IPCC) will agree that the current problems caused by climate change range from failing crops and hunger in Africa to species extinctions and rising sea levels.

The IPCC consists of scientists working with government delegates from over 100 nations. The group was locked in talks in Brussels to help overcome differences about a 21-page summary.

Some parts of the text were toned down from a draft but delegates sharpened other sections, including adding a warning that some African nations might have to spend 5 to 10 per cent of gross domestic product on adapting to climate change.

The report predicts water shortages that could affect billions of people, extinctions of species and a rise in ocean levels that could go on for centuries. It says human emissions of greenhouse gases are likely the main cause of warming.

The text also says climate change could lead to a sharp fall in crop yields in Africa, a thaw of Himalayan glaciers and more heatwaves for Europe and North America.

The IPCC report makes clear climate change, blamed mainly on human emissions of greenhouse gases from burning fossil fuels, is no longer a vague, distant threat.

Neil Adger, a British lead author of the report, said, "The whole of climate change is something actually here and now rather than something for the future."

Friday's report will be the second by the IPCC this year. In February, the first said it was more than 90 percent probable that mankind was to blame for most global warming since 1950.