Jonathan Adler explains why it is that the science of climate change is really not a critical issue in the EPA endangerment finding or the debate that is likely to ensure:

The proposed findings will now go through a 60-day public comment period. Shortly thereafter, the findings will be finalized. Industry and anti-regulatory groups will almost certainly challenge the findings in court, and their legal challenges will almost certainly fail. Even if one doubts the accumulated scientific evidence that anthropogenic emissions of greenhouse gases contribute to climate change and that climate change is a serious environmental concern, the standard of review is such that the EPA will have no difficulty defending its rule. Federal courts are extremely deferential to agency assessments of the relevant scientific evidence when reviewing such determinations. Moreover, under the Clean Air Act, the EPA Administrator need only “reasonably . . . anticipate” in her own “judgment” that GHG emissions threaten public health and welfare in order to make the findings, and there is ample evidence upon which the EPA Administrator could conclude that climate change is a serious threat. This is a long way of saying that even if climate skeptics are correct, the EPA has ample legal authority to make the endangerment findings.

What will happen next is fully about costs, jobs, and politics.