Economist: SOOT--also known as black carbon--heats up the atmosphere because it absorbs sunlight. Black things do. That is basic physics. But for years the institutions that focus on climate policy have played down the role of pollutants such as black carbon that stay in the atmosphere for a short time, and concentrated on carbon dioxide, which, once generated, tends to remain there. That may soon change.
On January 15th, the fifth day that smog-darkened Beijings air-quality index was registering hazardous...