Sustainability measurement
Coal
### Coal

Peak coal is significantly further out than peak oil, but we can observe the example of [anthracite](/wiki/Anthracite_coal "Anthracite coal") in the US, a high grade coal whose production peaked in the 1920s. Anthracite was studied by Hubbert, and matches a curve closely.[GEO 3005: Earth Resources](http://www.geo.umn.edu/courses/3005/resource.html)  Pennsylvania's coal production also matches Hubbert's curve closely, but this does not mean that coal in Pennsylvania is exhausted—far from it. If production in Pennsylvania returned at its all\-time high, there are reserves for 190 years. Hubbert had recoverable [coal reserves worldwide](/wiki/Coal%23World_coal_reserves "Coal#World coal reserves") at 2500 × 109 metric tons and peaking around 2150(depending on usage).

More recent estimates suggest an earlier peak. *Coal: Resources and Future Production* (PDF 630KB ), published on April 5, 2007 by the Energy Watch Group (EWG), which reports to the German Parliament, found that global coal production could peak in as few as 15 years. Reporting on this Richard Heinberg also notes that the date of peak annual energetic extraction from coal will likely come earlier than the date of peak in quantity of coal (tons per year) extracted as the most energy\-dense types of coal have been mined most extensively. A second study,
*The Future of Coal* by B. Kavalov and S. D. Peteves of the Institute for Energy (IFE), prepared for European Commission Joint Research Centre, reaches similar conclusions and states that
""coal might not be so abundant, widely available and reliable as an energy source in the future".

Work by [David Rutledge](/wiki/David_Rutledge_%28engineer%29 "David Rutledge (engineer)") of [Caltech](/wiki/Caltech "Caltech") predicts that the total of world coal production will amount to only about 450 [gigatonnes](/wiki/Gigatonne "Gigatonne")."Coal: Bleak outlook for the black stuff", by David Strahan, [New Scientist](/wiki/New_Scientist "New Scientist"), [Jan. 19, 2008, pp. 38\-41](https://www.newscientist.com/channel/earth/mg19726391.800-coal-bleak-outlook-for-the-black-stuff.html).
 This
implies that coal is running out faster than usually assumed.

Finally, insofar as global [peak oil](/wiki/Peak_oil "Peak oil") and peak in natural gas are expected anywhere from imminently to within decades at most, any increase in coal production (mining) per annum to compensate for declines in oil or NG production, would necessarily translate to an earlier date of peak as compared with peak coal under a scenario in which annual production remains constant.


What does this imply about coal running out?