The piece “Super fracking” by Donald Turcotte, Eldridge Moores, and John Rundle (Physics Today, August 2014, page 34) was quite informative.
The authors state that “carbon dioxide emissions from power plants have been reduced by about a factor of two.” That may be true if one only takes the US into consideration, but it does not account for the displacement of US coal production to Europe,1 where it is now a low-cost fuel that is producing, one imagines, a similar amount of CO2 as it did in the US.
Another statement that requires some caution concerns the likelihood of an earthquake occurring during hydraulic fracturing. The authors suggest that the probability of a magnitude 4 earthquake is extremely low. Although, again, that may be true, the analysis does not cover water-disposal activity: The effects of long-term pressure buildup in disposal wells can produce earthquakes of greater magnitude than hydraulic fracking per se. One such quake in Oklahoma was reported2 at magnitude 5.6.
The authors then state that fracking is a “successful tool for economically extracting oil and gas” (my italics). That is quite a bold claim and one that in the US is quite contentious, at least for gas production. Witness the 2012 remark from ExxonMobil CEO Rex Tillerson that the company and others were “losing our shirts” on shale gas.3
