OnEarth takes a close look at why exactly Warren Buffett has been sniffing around Wyoming coal mines lately. Short answer: China wants coal. As George Black explains:

Although worldwide energy-related CO2 emissions rose more last year than at any time since 1969, and the use of coal grew faster than that of any other fossil fuel, U.S. demand has actually flatlined. In 2000 coal accounted for just over half of our electricity supply. By 2010 it was down to 45 percent. …

Asia is a different matter. … [C]ompanies like Peabody and Arch Coal are convinced that Asian demand has triggered a "supercycle" that will last at least 20 years, and talk in the industry is of exporting more than 100 million tons annually.

One economist makes the argument to Black that lower prices for coal would take away China's incentives to invest in cleaner energy. But China has plenty of incentives to invest in cleaner energy, not least that they want to get out ahead of us while we're still trying to make money off of fossil fuels. Silly us!