Have Chinese coal plants been keeping global warming in check?

Global warming theory predicts an overall temperature rise over decades, but slowdowns, and even brief periods of cooling are not only possible; they’re inevitable. The climate system is complex and influenced by ocean currents, wind patterns, changes in vegetation and ice cover and dust particles in the air.

The decade that just ended is a case in point. While it was the warmest ten years on record, temperatures didn’t rise as fast during the 2000s as they did for the previous 30 years or so. And while they aren’t at all surprised by this, scientists are still trying to figure out why it happened.

One culprit named in a new study is the coal plants in China, according to a new study just released. If unchecked by pollution controls, the sulfur spewing from their smokestack creates atmospheric particles that reflect some sunlight back into space, counteracting the warming effect from rising amounts of CO2.

China has been installing pollution controls on those plants. Without sulfate particles to counter the effects of CO2, says Robert K. Kaufmann, of Boston University’s Center for Energy and Environmental Studies, "there could be a big increase in warming -- and we’ve already seen that happening in 2009 and 2010. The hiatus is over."