The Chinese government announced Wednesday it would cap coal use by 2020. This staggering reversal of decades of Chinese energy policy was the inevitable result of China's recent pledge to peak CO2 use in 2030 or earlier, especially when combined with goals to slash air pollution. Here's why.
According to the International Energy Agency, at current emission rates, by 2040 the world will release all the carbon dioxide it can afford to if it wants to keep global warming to manageable levels.
The new U.S.-China climate deal greatly increases the chance of a global agreement in 2015 that could put the world on a path toward avoiding catastrophic warming. It also ensures that carbon-free energy will be the dominant source of new energy in the coming decades.