ouncy music and colouring book graphics introduce “A Look Underground,” a short video uploaded to YouTube last year by the Calgary-based Encana Corporation “to educate children about natural gas development.” In the demonstration, engineer Mark Taylor explains the principles of hydraulically fracturing shale and recovering natural gas to a dozen kids ranging from toddlers to preteens. The children stand gathered around a structure built from cupcakes arranged in a horseshoe, its top iced a vivid green and decorated with plastic trees and farm animals. A thick layer of white icing represents the shale layer below. Taylor shows how drillers push steel pipe down deep through the chocolate “earth” to the coveted shale, an operation depicted with plastic tubing. Next, he says, “we basically load it up with explosive charges like big firecrackers, and we blast holes into spots all along the way, so the gas can come out of the white shale here and into our well.”

It’s not a bad description of the process that has transformed North America’s fuel forecast and global energy politics within the lifetime of Taylor’s audience. And the subtext is one the gas industry hopes consumers will easily digest: that unconventional natural gas is as wholesome and safe as kindergarten. The hydraulic fracturing the video describes, also known as hydro-fracking, or simply fracking, is the sine qua non of the new gas, the key that has unlocked massive supplies of fossil energy once thought to be out of reach. Conventional gas sits in discrete underground pools; all it takes to get at it is to stick a straw down into the right place. But geologists have long known that much more natural gas remains sequestered in the minute pockets between the grains of certain types of rock. In most cases, fracking uses water with additives to shatter the rock, creating fissures that enable the gas to flow into a well.

First used to access gas in the American and Canadian West, where the process has been used on tens of thousands of wells, fracking has made a growing number of unconventional gas beds viable for recovery. Formations rich in gas micro-pores are strung in a patchy U across North America, beginning in British Columbia’s far northeast; trailing down the eastern slope of the Rocky Mountains (with significant stores through Alberta, Saskatchewan, and North Dakota); and then sweeping across the southern US to a long band of gas-bearing shale that runs under half a dozen eastern states and up into Canada. The last in particular — the Marcellus Shale, which lies tantalizingly close to the energy-hungry markets of the eastern seaboard — has the industry salivating. Based on usage today, according to the Canadian Society for Unconventional Gas, Canada has enough frackable gas to maintain current production for about a hundred years.

Fracking has altered North America’s fuel supply so explosively that a gas bubble has saturated the market, driving down prices in recent quarters. Simultaneously, however, estimates of the abundance of unconventional gas have rescued producers from inevitable eclipse as conventional production declines. Instead, the industry has embraced a bold new ambition: to position gas as the economy’s energy mainstay, a fossil fuel as cheap and plentiful as coal, only cleaner and greener. Environmentalists, meanwhile, link fracking to a host of injuries to water, air, humans and wildlife, and to the integrity of ecosystems. France has banned the practice, and the European Union is toying with similar prohibitions.

Industrialized humanity exhausts more than 500 exajoules of energy each year, for every purpose from growing food to opening the door. That’s roughly the equivalent of setting off a Hiroshima-sized bomb every five seconds. In Canada, gas supplies more than one-quarter of the energy we use (I heated my shower with it this morning) but barely half the amount we extract from coal and oil — sources that environmentalists deplore even more than frack gas. And as much as we might like to see those sources replaced by renewable energy, that also comes with limits and costs.

The story of fracking, then, is a story about risk, about those unavoidable contingencies we face and trade off every day as individuals and communities, weighing our wants (income, a warm home, a good Christmas sales season) against the effort, cost, or hazards of getting it: a collision on the commute, a dammed-up river somewhere, a slightly warmer climate. Rarely is the answer kindergarten-simple.

ast of Calgary, the snow-dusted prairie is the white of the December sky. Dropping into a coulee, the bare two-lane blacktop turns sharply right at the hamlet of Rosebud, and I follow a side street buried under fresh snow before circling to a dead end in front of Jessica Ernst’s house. A shy environmental biologist with long, straight, greying hair, she ushers me in and offers me hand-knitted socks to ward off the floor’s chill. Her living room and kitchen are cluttered with the artifacts of daily life: house keys, small tools, correspondence — lots of correspondence. Several walls hold examples of her one financial indulgence, art. Prominent are works by Marianna Gartner, a Vancouver artist who sets disturbing portraits of pale children — some with tattoos, or skulls for heads — in surreal landscapes that might be dreams or nightmares.

Ernst’s reality has been mostly the latter since early 2005, when she began to suspect something was wrong with her plumbing. Her bathtub faucet whistled loudly, as though air were being forced out of it. Small black grains clogged her kitchen tap. The water in her toilet fizzed as if it were full of Alka-Seltzer. She developed a skin rash so severe that her doctor compared it to industrial burns. In a touch out of Stephen King, her dogs backed away from their water dishes.

Ernst has worked in the oil patch for decades, mainly advising companies on how to lighten their impact on the communities where they operate. She knew that Encana, one of North America’s largest unconventional gas producers, with operations in the US, BC, and Alberta, had been drilling in a coalfield beneath the nearby hills, known as the Horseshoe Canyon Formation. She also knew that her own water well, which had run clean and pure since 1986, drew on parts of that same formation. She conducted a simple test, running tap water into a mug, then lighting a match and waving it beside the lip. A yellow-orange flame spread across the water. For her next homespun experiment, she partly filled a plastic pop bottle with water and tightened the cap. A minute later, holding a lit match near the bottle’s neck, she unscrewed the cap. The bottle exploded, shooting a blue flame like a rocket.