GLOBAL warming has accelerated and the carbon emitted this century will continue to warm the Earth for more than a thousand years, according to the scientific advice commissioned by the world's governments.
Officials from about 180 governments, including Australia, will meet in Paris next week for the first Intergovernmental Panel on Climate Change in six years.
Confidential research to go to the meeting predicts rainfall will increase in the tropics over this century. But it is likely rainfall will diminish in the regions near the tropics, which includes most of the inhabited parts of Australia.
The reductions in rainfall due to global warming could be as much as 20 per cent under some of the scenarios the working group finds plausible.
The updated expert scientific advice for the meeting is considerably more confident that global warming is caused by man-made emissions of greenhouse gases. The best assessment for the last climate change panel meeting put the likelihood at more than 66 per cent that human activity was to blame. But the scientists now assert it is more than a 90 per cent likelihood, say sources familiar with the confidential advice.
The likelihood of a continuing global trend to more warm days and fewer cold ones is rated greater than 99 per cent.
Research on the physical science of climate change, prepared by 49 of the foremost experts, finds warming caused by carbon emissions increased by 20 per cent in the past 10 years, the fastest in at least 500 years.
The scientists predict that the average global temperature will rise by 0.2 degrees in each of the next two decades, double the rate of warming that would have occurred if greenhouse outputs had been stabilised at 2000 levels.
The advice to the governments says man-made carbon dioxide emissions already under way in the 21st century - even if they were to cease at the end of the century - will continue to exert a warming effect for more than a thousand years because it takes time for the gas to leave the Earth.
Meanwhile, the Prime Minister, John Howard, yesterday brushed off an accusation from the Australian of the Year, Tim Flannery, that his Government had dragged the climate change chain. Mr Howard said he was not "bowled over by some of the doomsday scenarios".
Among other effects the scientists predict are that sea ice will shrink in the Arctic and Antarctic under all plausible scenarios, extremes including heatwaves will continue to become more frequent and snow cover will contract. There are projected to be fewer tropical cyclones, but their intensity will grow.
In a projection less troubling than the previous report, the scientists now believe the rise in the sea level will be smaller. The scientists are uncertain of the strength of the feedback effects that will accompany global warming - that is, its propensity to be self-perpetuating.
The findings will be the basis for debate and negotiations over measures governments might take to address global warming.
