Evidence that global warming is man-made is getting stronger, the head of a UN panel of climate scientists said, in a further blow to sceptics who argue rising temperatures can be explained by natural variations.
Rajendra Pachauri spoke on the sidelines of a conference in Qatar where 200 nations are trying to reach a deal to cut emissions of greenhouse gases to avert floods, droughts, heatwaves and mounting sea levels.
The influential UN climate panel said the probability human activity was the main cause of climate change was "at least 90 per cent" in its last report in 2007.
Pachauri told Reuters late on Wednesday he expected the panel would raise the level of that likelihood even higher in its next report, due in 2013.
It is an annual ritual: nearly 200 nations sit down at the end of each year for two weeks of glacially paced negotiations meant to stop global warming. Meanwhile, leading scientific and economic bodies warn the best evidence suggests time is fast running out to cut greenhouse gas emissions.
Starting Monday it is the turn of the oil-dominated Qatar to host the latest major United Nations’ climate summit.
There is good news and bad news about the clean energy transition. The good news is that half the new electric generating capacity installed worldwide in 2008-2010 was renewable. The bad news is that half wasn’t.
To avoid rapid global warming and its attendant human and economic risks, we need to accelerate the transition. We need to do more than slower growth in the use of fossil fuels: we need to cut their use substantially. This will require significantly ramped up investments worldwide in energy efficiency and clean energy.