The five-year mean global temperature has been flat for the last decade, which we interpret as a combination of natural variability and a slow down in the growth rate of net climateforcing.
"We used computer models to simulate the climateforcing impact of the observed changes in soot concentrations in Greenland snow during the past 215 years, " said co-author Mark Flanner from the University of California.
Some lobbyists have argued that UK's unilateral climate targets are forcing up energy prices and driving manufacturing jobs abroad, but the committee found this false.
But the main external candidate is solar, and more work is required to improve the "paleo" solar forcing record and to understand how the climate system responds both globally and regionally to solar forcing.
Based upon data from the paper, the cooling climate impact from the decrease in the average global cloud height more than offset the positive forcing from an increase in greenhouse gases from human activities in the last decade.