And they do, but only in terms of the threat it poses to their enormous profits.

For example, in its advertising, ExxonMobil leans heavily on the $100 million the company has pledged to finance the Global Climate and Energy Project, a research effort based at Stanford University. GCEP's avowed goal is to develop "energy technologies that are efficient, environmentally benign, and cost-effective when deployed on a large scale," which is no doubt a worthy effort.

However, let's put that pledge of $100 million — to be spread out over a 10-year period — into a little perspective. That contribution amounts to 0.0028 percent — rounded up — of ExxonMobil's $36 billion profit last year alone. In fact, it wouldn't be surprising if the company eventually spends as much on TV commercials bragging about its GCEP contribution as it does on the contribution itself.

Furthermore, while they're playing good guys on TV and in their philanthropy, ExxonMobil and other energy companies — including Atlanta-based Southern Co. — are playing quite a different role behind the scenes in Washington, where they've deployed an army of lobbyists and geysers of campaign cash to ensure that the federal government does nothing whatsoever about the problem. That effort includes funding of industry front groups that try to peddle the increasingly ludicrous line that mankind's role in climate change is still uncertain.

In that approach, the nation's greenhouse naysayers are borrowing directly from tactics perfected by the tobacco industry in its decades-long fight to avoid government regulation.

The tobacco industry, like the energy lobby, wielded enormous economic and political clout. All it needed for leverage was an opening — just the barest illusion of doubt about the dangers of cigarette smoking. As long as it could claim that more research was needed to answer these last remaining questions, Big Tobacco could continue to fend off the regulation that would undercut its profits.

That's exactly what ExxonMobil and others are doing now. They concede that the planet is warming, just as greenhouse theory predicts. They also concede that the concentration of greenhouse gases is increasing, with most of the increase attributed to fossil fuels. What's lacking, they claim, is proof the phenomena are connected.

When the tobacco industry pulled that ploy, they knew deep down inside that they were selling a deadly product to addicted people, but the position of the energy lobby is even more reprehensible because of the planetary scale of damage being wrought.

Cigarette smoking causes cancer, a terrible and often fatal disease in those who partake. But global warming is altering the chemical composition of our atmosphere and transforming the climate that underlies all forms of life on this planet, and it does so more or less permanently.

There's another parallel as well. In recent years, tobacco company executives have become a target of public ridicule for defending the indefensible. But in truth their case had been so threadbare for so long that the only people who believed it were people who wanted to believe it.

As tobacco lawyers point out, anyone who didn't know 25 years ago that smoking causes cancer simply didn't want to know.

The same is true of global warming. Yes, the ExxonMobils and Southern Cos. of the world are trying to create as much doubt as possible about climate change. But as the scientific consensus hardens, the only way to buy their argument is to really want to buy it.

As President Bush himself admits, we are addicted to cheap and plentiful oil, and attempts to rationalize away the facts on global warming sound all too much like the stories that addiction counselors hear almost every day from people desperate to preserve their habits.

"Yes, I may drink a fifth of Jack Daniels a night, and yes, my family and professional life may be collapsing," the addicts say. "But there's no proof the two are connected. Maybe it's just bad luck."

Typically, that kind of denial works until the addict hits bottom. I hate to think of what a planet hitting bottom would look like.

• Jay Bookman is the deputy editorial page editor. His column appears Thursdays and Mondays.