From the not so conservative salon http://www.salon.com/news/politics/w...d_fossil_fuels
The implications for energy security are startling. Natural gas may be only the beginning. Fracking also permits the extraction of previously-unrecoverable “tight oil,” thereby postponing the day when the world runs out of petroleum. There is enough coal to produce energy for centuries. And governments, universities and corporations in the U.S., Canada, Japan and other countries are studying ways to obtain energy from gas hydrates, which mix methane with ice in high-density formations under the seafloor. The potential energy in gas hydrates may equal that of all other fossils, including other forms of natural gas, combined.
If gas hydrates as well as shale gas, tight oil, oil sands and other unconventional sources can be tapped at reasonable cost, then the global energy picture looks radically different than it did only a few years ago. Suddenly it appears that there may be enough accessible hydrocarbons to power industrial civilization for centuries, if not millennia, to come.