Hydraulic fracturing — "fracking" — has already transformed the U.S. economy. New and improved drilling techniques have enabled companies to extract oil and gas from once-inaccessible shale formations in Texas, North Dakota, and elsewhere.

So what about Europe? Will they ever join in on the fracking craze? As this map from the Economist shows, there are plenty of shale deposits over on the other side of the Atlantic. Yet countries like France and the Netherlands have put a moratorium on fracking, for fear that the chemicals used in the process could contaminate local water supplies. Others, like Austria, have such strict regulations that shale-gas drilling is still uneconomical:

That leaves Eastern Europe, where countries like Poland are hoping that shale drilling can create jobs and lessen dependence on Russia's natural gas. Yet even here, progress has been slow — only a few test wells have been drilled, and plenty of work remains to better understand the region's geology. The Economist estimates that shale gas won't start flowing for at least a decade, and maybe longer:

Oil companies will send people and equipment where the ride is easiest and the deals are tastiest, which explains why drilling rigs are scarce in Europe. Nearly 1,200 of them scoot around America’s shale beds; in Poland they number only half a dozen.

But even if the welcome mat is rolled out now, it will be a long time before Europe can catch up with America. It may take five years to assess whether shale gas exists in commercial quantities, another five before production starts and then a few more before shale could provide a significant addition to supplies: in short, a fracking long time.

In the meantime, Europe's power plants are turning back to coal — the most carbon-intensive of all fossil fuels. That's because natural gas is still expensive on the continent and coal has become relatively cheap (in part because the United States is exporting more of its unused coal abroad). In theory, greater gas fracking could change that dynamic, but that might not happen for years.