'Many scientists say they expect a revival of warming in coming years. Theories for the pause include that deep oceans have taken up more heat with the result that the surface is cooler than expected, that industrial pollution in Asia or clouds are blocking the sun, or that greenhouse gases trap less heat than previously believed. The change may be a result of an observed decline in heat-trapping water vapor in the high atmosphere, for unknown reasons. It could be a combination of factors or some as yet unknown natural variations, scientists say...'The climate system is not quite so simple as people thought,'said Bjorn Lomborg...'My own confidence in the data has gone down in the past five years,' said Richard Tol, an expert in climate change and professor of economics at the University of Sussex in England...Greenhouse gas emissions have hit repeated record highs with annual growth of about 3 percent in most of the decade to 2010, partly powered by rises in China and India. World emissions were 75 percent higher in 2010 than in 1970, UN data show'