BECAUSE WE HAVE to start somewhere, I bought my first batch of energy-saving light bulbs the other day. I admit it: Al Gore persuaded me to do this.

We recently rented "An Inconvenient Truth," his movie about the threat of global warming and the changing climate. The next day I bought a copy so I could lend it out to people.

The inconvenient truth is this: Global warming, caused by human activity, is endangering our planet and the health of future generations--and it is our responsibility to make the lifestyle changes that will help reverse it.

Climate change is undeniable and irrefutable. I don't care that those who choose to ignore the facts are endangering themselves; I care that they are putting my kids and their kids at risk.

The United States is the biggest contributor to the problem, and government at every level must do better. Take the Spotsylvania County Board of Supervisors, for instance. By letting the 2 percent gas tax prevent the county from joining the Virginia Railway Express, the board is being penny wise and pound stupid.

Supervisors have the opportunity to get automobiles off Interstate 95, to enhance other public transportation services, and to improve bottlenecks that cause vehicles to spew poisons into the air as they idle, and they choose not to accept it. They choose to reject progress.

It was a similar failure to lead that delayed public acceptance of the value of seat belts and the dangers of smoking. Such foot-dragging costs lives, just as it will if we fail to act--in the face of incontrovertible evidence--on the threat of global warming.

Hundreds of U.S. mayors have pledged to work toward meeting the goals of the Kyoto Protocol, the international agreement to reduce greenhouse-gas emissions. The mayors are doing this because theirs is one of only two industrialized nations (Australia being the other) that have neither signed the agreement nor come up with an alternative plan.

The cost, of course, is always a hurdle--just as it was for landmark environmental legislation such as the Clean Water Act and the Clean Air Act. The economy survived these mandates despite the predictions of various corporate and political leaders to the contrary. Indeed, without such legislation our survival would be in doubt.