"Let's go read the Clean Air Act together, shall we?"

(Shorter DC Circuit on upholding EPA's carbon rules.)

It's always nice to see a undiluted decision upholding the procedural strengths of these wonders of environmental law -- built long ago by a now-lost people, we cannot even imagine how such things might be constructed now.

There is a line of heritage in these laws that forbids judicial balancing, saying that no human or social consideration can overcome the primacy of the environment, and the importance of preventing environmental damage.  That line is dying out -- it was written out of the Endangered Species Act, for example.  But it's nice to see it bolstered here: "Oh, you mean someone might go out of business because EPA is regulating carbon?  It might cause some complicated and expensive social adjustments?  Tough.  Danger means danger, no matter how inconvenient or expensive it is to recognize."

That EPA adjusted the statutory thresholds to accommodate regulation of greenhouse gases emitted by stationary sources may indicate that the CAA is a regulatory scheme less-than-perfectly tailored to dealing with greenhouse gases. But the Supreme Court has already held that EPA indeed wields the authority to regulate greenhouse gases under the CAA. See Massachusetts v. EPA. The plain language of § 202(a)(1) of that Act does not leave room for EPA to consider as part of the endangerment inquiry the stationary-source regulation triggered by an endangerment finding, even if the degree of regulation triggered might at a later stage be characterized as “absurd.”

Note also that the court accepts the EPA's standard of "very likely" that GHGs are responsible for the deleterious effects of global warming.  They do not require "certainty":

But the existence of some uncertainty does not, without more, warrant invalidation of an endangerment finding. If a statute is “precautionary in nature” and “designed to protect the public health,” and the relevant evidence is “difficult to come by, uncertain, or conflicting because it is on the frontiers of scientific knowledge,” EPA need not provide “rigorous step-by-step proof of cause and effect” to support an endangerment finding. Ethyl Corp. v. EPA, 541 F.2d 1, 28 (D.C. Cir. 1976). As we have stated before, “Awaiting certainty will often allow for only reactive, not preventive, regulation.” Id. at 25. ... Requiring that EPA find “certain” endangerment of public health or welfare before regulating greenhouse gases would effectively prevent EPA from doing the job Congress gave it in § 202(a)—utilizing emission standards to prevent reasonably anticipated endangerment from maturing into concrete harm.

Reaffirming the precautionary principle in environmental regulation is a BFD.

It's also kind of fun to see the court engage in a point-by-point explanation of why the Climategate emails are completely irrelevant to the EPA's rulemaking:

Only two of the errors they point out seem to be errors at all, and EPA relied on neither in making the Endangerment Finding. First, as State Petitioners assert, the IPCC misstated the percentage of the Netherlands that is below sea level, a statistic that was used for background information. However, the IPCC corrected the error, and EPA concluded that the error was “minor and had no impact,” and the Endangerment Finding did not refer to the statistic in any way. Second, the IPCC acknowledged misstating the rate at which Himalayan glaciers are receding. EPA also did not rely on that projection in the Endangerment Finding.

On the other hand, I can understand why the anti-carbon folks were upset.  It's almost as if someone had passed legislation preventing us from having accurate information on sea-level changes!  Oh, wait.