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.