The U.S. Geological Survey has reported that economically extractable coal reserves in the United States, typically estimated at some 240 years worth, could be substantially less than previously thought – perhaps only half the previously estimated reserves.

The news is consistent with the findings of a 2007 National Research Council study and is similar to other reports of overestimates of economically recoverable coal reserves in other countries.

China is the world’s largest coal producer – mining twice as much as the United States, which is the second largest producer. The Energy Watch Group has predicted that Chinese coal production will peak in 2015 and will go into a steep decline after 2020. The most optimistic estimates put Chinese peak coal production at around 2030.

The UK and Germany were once major coal producers. UK production peaked in 1913 and German production in 1958. Canadian production peaked in 1997.

Russia has large untapped reserves of coal but most of it is "dirty" brown coal in difficult locations.