CLIMATE change is real and set to cause dramatic temperature rises in the coming century, according to a leaked draft of a major United Nations report.
The study, by a panel of 2,500 scientists who advise the UN, is the most complete overview of climate-change science and will be published next month by the Intergovernmental Panel on Climate Change (IPCC) after a final review.
The IPCC's reports are regarded by many environmentalists as cautious, because the findings have to be agreed by member states including oil-producing countries such as Saudi Arabia.
The draft, which was leaked by scientific sources, says it is "very likely" - more than a 90 per cent chance - that human activities, led by burning fossil fuels, are to blame for warming since 1950. The previous report in 2001 said the link was "likely".
It projects temperatures will rise by 2-4.5C (3.6-8.1F) above pre-industrial levels, with a "best estimate" of a 3C (5.4F) rise, assuming carbon-dioxide levels are stabilising at about 45 per cent above current levels. The European Union says any temperature rise above 2C will cause "dangerous" changes.