Global warming lull down to China’s coal growth
The lull in global warming from 1998 to 2008 was mainly caused by a sharp rise in China’s coal use, a study suggests.
The absence of a temperature rise over that decade is often used by “climate sceptics” as grounds for denying the existence of man-made global warming.
But the new study, in Proceedings of the National Academy of Sciences, concludes that smog from the extra coal acted to mask greenhouse warming.
China’s coal use doubled 2002-2007, according to US government figures.
Although burning the coal produced more warming carbon dioxide, it also put more tiny sulphate aerosol particles into the atmosphere which cool the planet by reflecting solar energy back into space.
The researchers conclude that declining solar activity over the period and an overall change from El Nino to La Nina conditions in the Pacific Ocean also contributed to the temperature plateau.
Lead researcher Robert Kaufmann from Boston University, whose research interests span climate change and world oil markets, said the study was inspired by “sceptical” questioning.