From the web…
That’s CalTech engineer David Rutledge, who spoke to EarthSky at a recent science meeting. He said governments around the world have overestimated coal reserves or, the amount of coal still available for energy use.
David Rutledge: That estimate, at least for these trends, appears to be high, for coal.
To figure out how high, Rutledge studied trends in countries that have already run out of coal.