OPPOSITION to fracking has been considerable, if not unanimous, in the global green community, and in Europe in particular. France and Bulgaria, countries with the largest shale-gas reserves in Europe, have already banned fracking. Protesters are blocking potential drilling sites in Poland and England. Opposition to fracking has entered popular culture with the release of "The Promised Land," starring Matt Damon. Even the Rolling Stones have weighed in with a reference to fracking in their new single, "Doom and Gloom."

Do the facts on fracking support this opposition?

There is no doubt that natural gas extraction does sometimes have negative consequences for the local environment in which it takes place, as does all fossil fuel extraction. And because fracking allows us to put a previously inaccessible reservoir of carbon from beneath our feet into the atmosphere, it also contributes to global climate change.

But as we assess the pros and cons, decisions should be based on existing empirical evidence and fracking should be evaluated relative to other available energy sources.

And from the last portion of the conclusion:

Europe is currently increasing its reliance on coal while discouraging or banning fracking. If we are going to get our energy from hydrocarbons, blocking fracking while relying on coal looks like a bad trade-off for the environment.

So, should the United States and Europe encourage fracking or ban it? Short-run economic interests support fracking. In the experience of Pennsylvania, natural gas prices fall and jobs are created both directly in the gas industry and indirectly as regional and national economies benefit from lower energy costs. Europe can benefit from lessons learned in Pennsylvania, minimizing damage to the local environment.

The geopolitical shift that would result from decreasing reliance on oil, and more specifically on Russian oil and gas, is one that European politicians might not want to ignore. And if natural gas displaces coal, then fracking is good not only for the economy but also for the global environment.

But if fracked gas merely displaces efforts to develop cleaner, non-carbon, energy sources without decreasing reliance on coal, the doom and gloom of more rapid global climate change will be realized.

David Fuller's view The extraction and burning of fossil fuels is a messy process but mankind could not prosper without them. So-called clean or green energy is a nice idea. However, countries which have invested heavily in wind farms are now realising just how expensive, unreliable, inefficient, noisy, unsightly and hazardous for wildlife these installations are proving to be.

Solar power is preferable to windmills, not least because it can be used in small units attached to buildings, but it is certainly not a standalone system in most countries. Fossil fuel backup is required for all green energy technologies, which increases the costs considerably.

Pre-Fukushima, nuclear power was regarded as sort of green, albeit with terrifying leakage and waste disposal problems. Consequently, few countries are ready or willing to invest in new nuclear, which is almost certainly safer, although the spent fuel problem needs to be resolved by rendering it harmless.

Fortunately, US fracking technology has ended the 'peak oil' risk, because global sources of shale oil and natural gas are widely spread and vast. The US economy has been the enormous beneficiary of this unconventional oil and gas production to date. Other countries have access to the technology but political inertia has largely delayed their use to date, not least in Europe.

Paradoxically, Europe's green energy programmes have increased pollution because of the additional need for backup coal burning plants. Conversely, pollution has actually declined in the USA thanks to the amount of natural gas that is being produced and used. Moreover, the American economy is benefiting enormously from its energy cost advantage.