Sulfur Smoke Slowed Global Warming Slightly
As China soared quickly to world prominence, their coal use skyrocketed. The massive amounts of coal burned by the middle kingdom may have actually reduced the global greenhouse effect in the mid-2000s.
"People normally just focus on the warming effect of CO2 [carbon dioxide], but during the Chinese economic expansion there was a huge increase in sulfur emissions," which have a cooling effect, explained Robert K. Kaufmann of Boston University to the Associated Press. Kaufmann is lead author of a study published in Proceedings of the National Academy of Sciences that examined sulfur's role in slowing climate change in the 2000s.
Between 2003 and 2007, Chinese coal consumption doubled, accounting for a 26 percent increase in global coal use.
About that same time, global average temperatures increased slower than in the 90s and later 2000s.
In the rush to industrialize, China used coal plants without filters. Unfiltered coal smoke contains sulfur. And that air-borne sulfur blocked the sun's rays from ever reaching the Earth's surface.
But before you start burning brimstone to save the polar bears, think about this. Sulfur containing chemicals also cause acid rain and contribute to toxic smogs. That's why Chinese, and most other nations' power plants now install scrubbers to remove the sulfur from the smoke.
Sulfur's effect is short-lived. It drops out of the atmosphere after a few months to years, whereas carbon dioxide can stay in the atmosphere for centuries. That means the carbon dioxide keeps insulating the Earth long after the sulfur is no longer blocking the sunlight.
This isn't the first time industrial booms have masked the greenhouse effect. After World War II, industrial production soared, and sulfur slowed global warming, Kaufmann said.
Some have even suggested pumping sulfur into the atmosphere to act as a band-aid to climate change. But other research by Simone Tilmes of the National Center for Atmospheric Research has suggested that sulfur compounds would react with ozone high in the atmosphere and slow the healing of the hole in the ozone layer above Antarctica.
"While climate change is a major threat, more research is required before society attempts global geoengineering solutions," Tilmes told the Associated Press.
