Driving less? More than two-thirds of car owners already are. It's a natural reflex to $50-$70 tank fill-ups. But US drivers may also know it's time to pay a price to curb global warming. That may be one reason they reject the campaign stunt of urging a holiday for the federal gas tax.

US politicians can't have it both ways. Most seek the type of solutions for climate change that would raise energy costs, yet they are now trying to prevent the very kind of high pump prices that help drive conservation and green technology.

Next year, Democrats in Congress plan to pass antiglobal-warming measures that are sure to drive up consumer costs. Rather than prevent $4-a-gallon gas now, legislators should welcome it. One courageous lawmaker, John Dingell (D), who heads the House energy panel, even proposes a 50-cent hike in the gas tax.

World oil markets are doing the US a favor by imposing a form of tax that challenges energy profligacy and disregard for the planet's future. A gas price threshold has now been reached to influence behavior. SUV sales are down. Mass transit ridership and carpooling are up. More people want to live closer to work.

What do these lifestyle-altering trends signal? That Congress must impose a "carbon" tax on fossil-fuel use, from electric utilities to home furnaces to gas-guzzling vehicles.

Such a tax is a better tool than the alternative favored in Congress: a "cap and trade" system that would force only industries to curb greenhouse gases while allowing cleaner companies to sell permits to more polluting ones. The system is complex, inflexible, and easily abused.

A carbon tax (with progressive rebates for the poor) would directly make lawmakers accountable for taking action on global warming, while providing revenue for innovation in clean energy. In a February report, the Congressional Budget Office found a carbon tax would be five times more effective in reducing carbon emissions than a cap-and-trade market.

Is there a model for a carbon tax? Yes, Sweden has had one since 1991. While it has not been perfectly implemented, the Nordic nation of 9.2 million people has seen a 9 percent drop in carbon dioxide emissions – more than required under the Kyoto treaty – while maintaining a healthy economy and becoming a "clean tech" leader. A German environmental group finds Sweden has done the most of all countries to protect the climate. It also helps that the country relies on nuclear and hydro power for all its electricity.

Sweden, of course, has done more than simply tax fossil fuel. It's created bicycle lanes, encouraged "green" cars and buses, favored heat pumps over oil furnaces, put a toll on driving in Stockholm, and invested in renewable energies and recycling of waste heat, among other steps. The government now taxes vehicles based on carbon dioxide emissions rather than weight, helping Sweden become the leader in Europe in reducing carbon emissions from new cars.

The initial reason for a carbon tax was Sweden's dependency on imported fossil fuel. Now its success in improving national energy security has made it a global model for achieving climate security.

Most of all, Swedes still welcome the tax. Americans can accept a similar sacrifice rather than trying to roll back prices at the pump.