In his weekly address on Saturday, President Obama saluted the House of Representatives for passing Waxman-Markey, the gargantuan energy-rationing bill that would amount to the largest tax increase in the nation’s history. It would do so by making virtually everything that depends on energy - which is virtually everything - more expensive.

The president doesn’t describe the legislation in those terms now, but he made no bones about it last year. In an interview with the San Francisco Chronicle in January 2008, he calmly explained how cap-and-trade - the carbon-dioxide rationing scheme that is at the heart of Waxman-Markey - would work:

“Under my plan of a cap-and-trade system, electricity rates would necessarily skyrocket … because I’m capping greenhouse gases, coal power plants, natural gas, you name it … Whatever the plants were, whatever the industry was, they would have to retrofit their operations. That will cost money, and they will pass that [cost] on to consumers.’’

In the same interview, Obama suggested that his energy policy would require the ruin of the coal industry. “If somebody wants to build a coal-fired plant, they can,’’ he told the Chronicle. “It’s just that it will bankrupt them, because they are going to be charged a huge sum for all that greenhouse gas that’s being emitted.’’

The justification for inflicting this financial misery, of course, is the onrushing catastrophe of human-induced global warming - a catastrophe that can be prevented only if we abandon the carbon-based fuels on which most of the prosperity and productivity of modern life depend. But what if that looming catastrophe isn’t real? What if climate change has little or nothing to do with human activity? What if enacting cap-and-trade means incurring excruciating costs in exchange for infinitesimal benefits?

Hush, says Obama. Don’t ask such questions. “There is no longer a debate about whether carbon pollution is placing our planet in jeopardy,’’ he declared Saturday. “It’s happening.’’

No debate? The debate over global warming is more robust than it has been in years, and not only in America. “In April, the Polish Academy of Sciences published a document challenging man-made global warming,’’ Kimberly Strassel noted in The Wall Street Journal the other day. “In France, President Nicolas Sarkozy wants to tap Claude Allegre to lead the country’s new ministry of industry and innovation. Twenty years ago Allegre was among the first to trill about man-made global warming, but the geochemist has since recanted … Norway’s Ivar Giaever, Nobel Prize winner for physics, decries it as the ‘new religion.’ ’’

Closer to home, the noted physicist Hal Lewis (emeritus at the University of California, Santa Barbara) e-mails me a copy of a statement he and several fellow scientists, including physicists Will Happer and Robert Austin of Princeton, Laurence Gould of the University of Hartford, and climatologist Richard Lindzen of MIT, have sent to Congress. “The sky is not falling,’’ they write. Far from warming, “the Earth has been cooling for 10 years’’ - a trend that “was not predicted by the alarmists’ computer models.’’

Fortune magazine recently profiled veteran climatologist John Christy, a lead author of the 2001 Intergovernmental Panel on Climate Change report. With his green credentials, Fortune observed, Christy is the warm-mongers’ “worst nightmare - an accomplished climate scientist with no ties to Big Oil who has produced reams and reams of data that undermine arguments that the earth’s atmosphere is warming at an unusual rate and question whether the remedies being talked about in Congress will actually do any good.’’

No one who cares about the environment or the nation’s economic well-being should take it on faith that climate change is a crisis, or that drastic changes to the economy are essential to “save the planet.’’ Hundreds of scientists reject the alarmist narrative. For non-experts, a steadily-widening shelf of excellent books surveys the data in laymen’s terms and exposes the weaknesses in the doomsday scenario - among others, “Climate Confusion’’ by Roy W. Spencer, “Climate of Fear’’ by Thomas Gale Moore, “Taken by Storm’’ by Christopher Essex and Ross McKitrick, and “Unstoppable Global Warming: Every 1,500 Years’’ by S. Fred Singer and Dennis Avery.

If the case for a war on carbon dioxide were unassailable, no one would have to warn against debating it. The 212 House members who voted against Waxman-Markey last week plainly don’t believe the matter is settled. They’re right.