The nighttime satellite photos are a handy reference guide to man's creeping takeover of the planet. Densely packed southern England is a blanket of white light. Ditto the stretch between Washington, D.C., and Boston—in effect, one big city. As you move west in the United States, black becomes the dominant colour, interspersed with small islands of white. Wait, has a new megacity popped up in North Dakota?

It seems so, but they're not city lights. They're the gas flares from the vast Bakken shale field in the state's northwest, hard by the Saskatchewan and Montana borders. To the American oil and gas industry, electricity providers and the security-obsessed White House and State Department, the field is a godsend. Thanks to the Bakken formation and a few other big shale discoveries, the United States is turning into an energy superpower. The International Energy Agency expects the country's oil output to exceed Saudi Arabia's by 2015.

Many environmentalists consider shale gas (if not shale oil) a godsend too, because gas's carbon intensity is roughly half that of coal, the main fuel used in U.S. electricity generation. At least they did. Now they, and more than a few government geologists and climate change officials, are changing their mind about its use as the ideal transition fuel to a low-carbon economy. Evidence is mounting that shale gas and the way it's produced could actually accelerate global warming, not the opposite.

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The trouble is that there is such a glut of shale gas that a lot of it is being flared off—burnt at the source—spewing carbon dioxide in the air for precisely zero economic benefit. Even worse is the methane gas that seeps, or is purposely released, from the wells in ever-rising quantities. Methane, the main component of natural gas, is an atmospheric nightmare. Its potency for global warming is estimated to be at least 20 times greater than carbon dioxide's, and some scientists put it far higher, depending on the time period measured.

Shale has always had a PR problem. The so-called fracking process, in which water and chemicals are injected under pressure into the deep shale formations to crack the rock, releasing gas, has been blamed for earthquakes and soiled aquifers. If you look at the total environmental impact of shale gas production and consumption, it may be as bad as—or worse than— coal on the greenhouse gas (GHG) front.

If that is true, the calls to turn down the fracking volume will go from whisper to roar. A 2011 report by three Cornell University researchers, Robert Howarth, Renee Santoro and Anthony Ingraffea, concluded that shale gas is a disastrous transition fuel, though the industry bumpf would tell you otherwise. Over a 20-year horizon, they said, "the GHG footprint for shale gas is at least 20% greater than, and perhaps more than twice as great as, that for coal when expressed per quantity of energy available during combustion."

The flaring alone is a massive problem. The shale revolution, as it is billed, is turning the U.S. Midwest, Texas and other states into pincushions, as drilling rigs arrive by the hundreds. (Residents in many states own the mineral rights to their properties, so they have an overwhelming incentive to invite drillers onto their land in exchange for a cut of production revenues.) Satellite imagery makes it impossible to hide the flaring, much to the drillers' embarrassment.

A 2013 report by Ceres, an American non-profit group that works with investors to encourage sustainable economies, estimated that in the two years up to last May, the amount of natural gas flared in North Dakota alone grew 2.5 times, to 266 million cubic feet a day, thrusting the United States into the top 10 flaring countries, and putting it in the same club as enviro-rogues Russia and Nigeria. In 2012 alone, the North Dakota flaring emitted as much GHG as a million cars, Ceres said.

Gas venting and seeping (which is also known as fugitive emissions) from the shale gas wells are serious problems, too, because they release pure methane into the atmosphere. Burning those emissions would emit carbon dioxide. The Cornell study determined that, over the lifetime of an average well, 3.6% to 7.9% of total production is emitted as methane. That range, the authors said, would make a shale gas well up to twice as damaging as a conventional one.

The total volume of flared and vented gas in Alberta is huge, too. The Alberta Energy Regulator found that the volumes in 2012 rose 24.6% over the previous year, to 34.8 billion cubic feet.

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As the Alberta oil and gas industry, and the American shale industry, gallop ahead, GHG emissions will soar unless nearby markets can be found for all this gas. Given the glut that already exists in North America, that scenario is unlikely. When the battered coal producers claim they still have a future, they may be right. But who would have thought they could make their case on environmental grounds?