RUTHFULLY YOURS

As environmental disasters go, the explosion Saturday of a runaway train that destroyed much of the Quebec town of Lac-Mégantic, about 20 miles from the Maine border, will probably go down the memory hole.

It lacks the correct moral and contains an inconvenient truth.

Not that the disaster lacks the usual ingredients of such a moral. The derailed 72-car train belonged to a subsidiary of Illinois-based multinational Rail World, whose self-declared aim is to “promote rail industry privatization.” The train was carrying North Dakota shale oil (likely extracted by fracking) to the massive Irving Oil refinery in the port city of Saint John, to be shipped to the global market. At least five people were killed in the blast (a number that’s likely to rise) and 1,000 people were forced to evacuate. Quebec’s environment minister reports that some 100,000 liters (26,000 gallons) of crude have spilled into the Chaudière River, meaning it could reach Quebec City and the St. Lawrence River before too long.

Environmentalists should be howling. But this brings us to the inconvenient truth.

The reason oil is moved on trains from places like North Dakota and Alberta is because there aren’t enough pipelines to carry it. The provincial governments of Alberta and New Brunswick are talking about building a pipeline to cover the 3,000-odd mile distance. But last month President Obama put the future of the Keystone XL pipeline again in doubt, telling a Georgetown University audience “our national interest will be served only if this project does not significantly exacerbate the problem of carbon pollution.”

Did the explosion at Lac-Mégantic not significantly exacerbate the problem of pollution, carbon or otherwise? Why do environmentalists routinely frame political choices in the language of moral absolutes—save/destroy the planet; “don’t be mean, go green,” and so on—rather than as complex questions involving trade-offs that are best dealt with pragmatically?

When it comes to the question of how best to transport oil, environmentalists tend to act like rabbis being asked for advice on how best to roast a pig: The thing should not be done in the first place. So opposition to Keystone XL becomes an assertion of virtue, indifferent to such lesser considerations as efficiency (or succulence).

But the pig will be roasted. The oil will be pumped. What happens then?

Like water, business has a way of tracing a course of least resistance. Pipelines are a hyper-regulated industry but rail transport isn’t, so that’s how we now move oil. As the Wall Street Journal’s Tom Fowler reported in March, in 2008 the U.S. rail system moved 9,500 carloads of oil. In 2012, the figure surged to 233,811. During the same period, the total number of spills went from eight to 69. In March, a derailed train spilled 714 barrels of oil in western Minnesota.

Predictable, you would think. And ameliorable: Pipelines account for about half as much spillage as railways on a gallon-per-mile basis. Pipelines also tend not to go straight through exposed population centers like Lac-Mégantic. Nobody suggests that pipelines are perfectly reliable or safe, but what is? To think is to weigh alternatives. The habit of too many environmentalists is to evade them.

Perhaps this explains why the environmental movement has excelled ideologically and failed politically. As in fashion, green is a nice color that rarely wears well. So the whole world (minus your correspondent) agrees that climate change is an urgent threat to life as we know it, yet every U.N. megasummit to save the planet ends on a whimpering note. So all Americans are convinced that the threat of climate change is real, but President Obama had to use executive fiat to impose regulations on the coal industry that Congress would have rejected out of hand.

Perhaps this is also the reason climate science is so prone to scientific embarrassment. In 2001, the U.N.’s Intergovernmental Panel on Climate Change insisted that “global average surface temperatures [will rise] at rates very likely without precedent during the last 10,000 years,” and that they would rise sharply and continuously.

Yet in the 15 years since 1998, surface air temperatures have held flat, a fact now grudgingly conceded by the climate-science establishment, despite more than 100 billion tons of carbon dioxide having been pumped into the atmosphere over the same period. “Nature is far more imaginative than we are,” Stamatios Krimigis, the eminent Johns Hopkins physicist, said last month when readings from the Voyager spacecraft failed to match expectations for what it would find at the far edge of the solar system. That kind of humility in the face of data is tough for today’s environmentalists, who have staked so much on their own models, predictions and certitudes.

It’s a pity. The world needs a credible environmental movement. Conservation matters. So does the quality of water and air. In China and Russia today environmentalists have mounted the most effective (and often the most courageous) critique of the toxic combination of coercive states and corrupt businesses. In the developed world, urban life has been massively improved thanks to a keener environmental awareness.

But all that depends on an environmental movement that isn’t just another fire-and-brimstone religion, that wants to be part of a solution without castigating everyone else as part of the problem. In other words, a movement that is capable of reasoned thought.

The first application for a Keystone XL pipeline permit was filed with the U.S. State Department in 2008. Since then, the amount of oil being shipped on rails has risen 24-fold. Environmentalists enraged by this column should look at the photo of Lac-Mégantic that goes with it, and think it over.

Write to bstephens@wsj.com

A version of this article appeared July 9, 2013, on page A11 in the U.S. edition of The Wall Street Journal, with the headline: Can Environmentalists Think?.