AFTER THEY WERE DONE INVADING the civilizations of Northern Europe, the industrious Danes turned to building great ships, first out of wood, then steel. Now they employ a similar metal-and-rivet fabrication method to make windmills for Vestas, one of the largest turbine manufacturers in the world. This, after all, is also the birthplace of Lego; Danes are organized, rational, and easily assembled. The highest earners pay about a 60 percent income tax, and what they get in return is free universities, free medical care, and some really good, cheap cheese.

But how did Danes get to be so carbon goody-goody? In Copenhagen, I ask the man who should know: Lego chairman Mads øvlisen, who also serves on the United Nations' newly created Global Compact Board and drives an electric Citroën to work. After an eloquent briefing on the Vikings—"Danes believe they can change the world, and, therefore, they must!"—øvlisen tells me that Denmark's ability to look outward stems from its seafaring past. That, and its tradition of social equity, made sustainability highly desirable. "We are a tribal country," he says. "And that drives innovation and adaptation."

Geopolitics also played a part. In 1973, OPEC imposed an oil embargo against the U.S. and the Netherlands for supporting Israel's war against Syria and Egypt, and nearly quadrupled the price of petroleum for everyone else. The U.S. at the time imported about 35 percent of its oil; Denmark imported more than 90 percent. Keenly aware of their vulnerability, the Danes spent the next 30 years figuring out how to secure an energy-independent future, all without nuclear power, which parliament outlawed in 1982.

Now, remarkably, Denmark is about 150 percent self-sufficient. A net exporter of energy—most of it oil and natural gas from the North Sea—it also sells wind power to it neighbors.

The American response to the embargo, by comparison, was more of a cheap-oil-is-our-birthright hissy fit. In the late 1970s and early '80s, to be fair, the U.S. launched some serious alternative-energy schemes, complete with tax credits and federal funding for renewables, and for a brief moment California actually became the king of wind power. Then, during the Reagan era, federal and state subsidies expired, making it impossible for wind and solar to compete with oil and coal. Today, the U.S. imports nearly double the oil that it did in 1973—or about 60 percent of what it consumes. Wind power makes up less than 1 percent of the American electricity pie.

We can turn this around if we choose to, observers note. "This country is capable of sleeping for a long time," says former CIA chief James Woolsey, now an eco-minded energy-security specialist and vice president of Booz Allen Hamilton, a Virginia-based international consulting firm. "But when it wakes up, things move pretty fast, and that's what we're going to be seeing in the next few years, with a growing coalition of tree huggers, do-gooders, cheap hawks, evangelicals, venture capitalists, and Willie Nelson. Renewable-energy technologies," Woolsey adds, "can come faster than people realize."

Indeed, in western Indiana, of all places, there's a mini Samsø rising from the cornfields: Reynolds, population 550, is constructing a $9.5 million power plant to turn hog manure and other ag products into clean energy. Elsewhere, at least 333 mayors representing more than 54 million Americans have pledged to follow the Kyoto mandates for reducing greenhouse gases, without waiting for Washington.

But renewables like wind power still face some Hummer-size hurdles. "In the U.S.," says environmentalist Frances Beinecke, president of the Natural Resources Defense Council, "people still see wind power as futuristic and marginal." To that list, one could also add "ugly": a proposed wind farm off Nantucket, for example, faces strong opposition from locals who don't want turbines marring the view.

"Today we can point to Denmark and say, 'Hey, a Western country gets one-fifth of its electricity from wind.' It's doable," Beinecke says. "There's just a cultural divide we have to cross."