The report released here represented the fourth assessment since 1990 by the group, the Intergovernmental Panel on Climate Change of the United Nations, of the causes and consequences of climate change. But for the first time the group asserted with near certainty — more than 90 percent confidence — that carbon dioxide and other heat-trapping greenhouse gases from human activities were the main drivers of warming since 1950.

THE US wants the world's scientists to develop technology to block sunlight as a last-ditch way to halt global warming.

It says research into techniques such as giant mirrors in space or reflective dust pumped into the atmosphere would be "important insurance" against rising emissions, and has lobbied for such a strategy to be recommended by a UN report on climate change...