From the Telegraph.Co.UK website (article dated December 10, 2006):
Mankind has had less effect on global warming than previously supposed, a United Nations report on climate change will claim next year.
The UN Intergovernmental Panel on Climate Change says there can be little doubt that humans are responsible for warming the planet, but the organisation has reduced its overall estimate of this effect by 25 per cent.
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It also says that the overall human effect on global warming since the industrial revolution is less than had been thought, due to the unexpected levels of cooling caused by aerosol sprays, which reflect heat from the sun.
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...Julian Morris, executive director of the International Policy Network, urged governments to be cautious. "There needs to be better data before billions of pounds are spent on policy measures that may have little impact," he said.