The timing isn't coincidental: as the Copenhagen climate talks begin, the Environmental Protection Agency plans to issue a formal "endangerment" finding for carbon dioxide and other greenhouse gases. In doing so, the agency is giving the administration what amounts to a cattle prod. Having "found" that CO2 is a "public danger," and having taken the requisite administrative steps, the executive branch now believes it has the power to unilaterally impose carbon and greenhouse gas emissions caps on industry in the United States. This overhanging boot will threaten to drop until and unless Congress acts. It's a neat executive weapon to have -- one that, incidentally, the Bush administration chose not to take out of the locker, and one that the Obama administration decided to unsheathe as the president prepares to travel to Copenhagen.

"Climategate" aside, here's what we know: a blanket of greenhouse gases is suffocating the earth. The thickness of this blanket is highly correlated with human activity, including deforestation and development. Rising levels of carbon dioxide are acidifying oceans and destroying coral reefs -- the bottom of the food chain. Most scientists strongly believe, but do not know for sure, that temperatures will rise fairly steadily over the next century, throwing human life as we know it into chaos. It is hard to get rid of carbon dioxide, so the natural policy to reverse or stall the warming trend would be to reduce the amount of carbon emitted.  Much of the science is settled, but parts of it, particularly temperature projections, are subject to large margins of error -- though often, this error redounds to the benefit of those scientists whose projections were too conservative.

There is a small chance -- tiny even -- that anthropomorphic global warming is harmless; there is a somewhat larger chance that its effects can't be mitigated -- or that mitigation will be costly for development and gross domestic product.

Corporations are spending tens of millions of dollars to seize on that small chance,  to create a haze of science-sounding claims, to put together the shreds of doubt to seize on  overzealous projections by leading (but human) climate science -- to call the whole enterprise into question and to ensure that whatever scheme is implemented to reduce CO2 emissions, it will be done fairly and fairly slowly. (Example: data from tree ring measures since 1960 do not always correlate well with other proxies for temperature, including coral reefs. Most likely, the problem is one of measurement -- either a flaw in experimental design or a change in the measurement environment -- i.e., global warming itself. That's why scientists who model climate change tend to adjust for the unusual post-1960 density readings. Mostly, they've done so openly and repeatedly -- and there is plenty of vigorous debate about why they do so.)

They've been successful, although there's surely a correlation with the rise in general economic anxiety. American politics has allowed a false equivalency to perpetuate itself, which isn't surprising. In a highly religious country, it takes more than scientific consensus to drive policy and change minds. There is also a strong relationship between a vote against emissions caps and the like, the amount of carbon emitted by a district, its relative (lack of) weath and potential to be harmed by a mitigation scheme, and political conservatism. That's one reason why the policy debate has become so polarized. Again, it's not about evidence. It is compelling -- and remains so.

Climate skeptics who aren't motivated by money -- and there are some -- have appropriated the language and posture of the original heretic, Galileo, casting themselves as brave souls arguing against the consensus, shaming people who would otherwise shut out their dissenting voices. It's a neat trick in and of itself -- using scientific axioms to try and discredit science. In general, good science can and should incorporate the doubts, but climate science has become extraordinarily polarizing.

Climate change scientists aren't blameless. The future of planet earth is at stake, and while the evidence is on their side, they've also conceived of and executed a public relations campaign to convince the public and policymakers of the urgency of the problem. In doing so, they've simplified conclusions, at times, or deliberately pointed to worst case scenarios when the middle of the bell curve would do just fine. The science has remained cumulative and solid, but the selling of this science hasn't -- and that, if anything else, fuels the critics.

However valid one's feeling of exclusion is, it isn't a substitute for what science does: test and try to falsify. The theory of anthropogenic climate change has not been disproven. It is stronger today than ever before.

Domestically, it is going to be difficult for the administration to convince Congress to take another vote on climate change legislation in 2010. In mounting a campaign against the Waxman-Markey cap-and-trade bill in the House, the business lobby was very successful in scaring the bejeezus out of moderate Democrats. Today, they argue that cap-and-trade legislation amounts to a "tax" and that India or China -- which won't have to curb its emissions by the same magnitude -- will steal hundreds of thousands of U.S. jobs.

Dealing in probabilities here, is it preferable to accept a short-term anchor on economic growth in order to improve the health of the commons? Is this a political sustainable vote? It is not clear whether, in 2010, there are enough Democrats who will say yes. That's one reason why Congress will probably wait until the economy improves.