Kenneth P. Green [Resident Scholar, American Enterprise Institute]: "The EPA's issuance of an endangerment finding for the greenhouse gases was inevitable, given the 2007 decision of the Supreme Court in Mass. v. EPA [PDF file], and the stated intention of the Obama Administration to move ahead in compliance with the court's order. The endangerment finding opens up several potential pathways to greenhouse gas control.

First, EPA could continue as it has with other criteria pollutants under the Clean Air Act, and control greenhouse gases through regulation of large emitters and automobiles. Virtually every economist agrees that this is the worst possible way that the United States could choose to control greenhouse gas emissions.

Requiring Best Available Control Technology would be virtually certain to raise the costs of energy, goods, services, and transportation, while simultaneously adding additional barriers to the creation, maintenance, and updating of energy intensive industries and businesses. This in turn would cause significant economic contraction and job loss. As these are regulations, not cap-and-trade or a carbon tax, no revenue stream would be available to use in mitigating the harm to energy users, and the impacts of high prices would fall disproportionately on women, minorities, and the poor. Naturally, this process would be heavily litigious, as were the 1997 revisions of the National Ambient Air Quality Standards, which were held up in court for about 8 years after they were approved by the Administrator of the EPA.

Some suggest that the EPA's endangerment finding will prod Congress into enacting cap-and-trade legislation, in which Congress will enjoin EPA from regulating greenhouse gases under the clean air act. As we have written here this would be almost as bad an option as having EPA continue with regulating greenhouse gases under the Clean Air Act. But there is reason to doubt that Congress will enact cap-and-trade, as EPA's endangerment finding gives them a way to avoid Congressional (Democrat) responsibility for the inevitably negative consequences of cap-and-trade. Congress might well choose to simply say "there's no reason for cap-and-trade legislation now that EPA is going to handle greenhouse gas controls," effectively shielding themselves from the political consequences of a party-line enactment of economically damaging climate legislation. It would not be the first time that Congress has passed responsibility onto unelected (and largely unanswerable) bureaucrats who can always be trotted out and castigated in hearings when prices climb, industries relocate, and product diversity in the market shrinks as a result of regulatory proliferation.

All in all, EPA's endangerment finding adds another element of uncertainty into what US climate policy will be, who will design it, who will implement it, and how it will affect the economic well-being of Americans and American business. The Obama administration seemingly took an approach of flinging everything they had at the wall of greenhouse gas controls, hoping something would stick. What stuck is widely considered to be the single worst approach to regulating greenhouse gases that could be envisioned for the United States economy."