EPA’s final* ruling on CO2

The EPA has announced its final^* ruling on the CO₂ Endangerment Finding.

^*not even close to final.

Notably, they have completely abandoned any reliance on the DOE’s CWG report.

The EPA is not relying on new findings by the Administrator with respect to global climate change concerns under CAA section 202(a)(1) as a basis for the rescission or repeals and is not finalizing the alternative basis set out in section IV.B of the preamble to the proposed rule.

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With respect to commenters’ precautionary arguments, the EPA is not finalizing the proposed alternative basis for rescission and repeal based on a new climate science finding by the Administrator.

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Although the Administrator continues to harbor concerns regarding the scientific determinations underlying the Endangerment Finding, the EPA has decided not to finalize this scientific alternative rationale at this time.

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For similar reasons, and in light of concerns raised by some commenters about the draft report authored by the U.S. Department of Energy’s Climate Working Group (CWG), the EPA is not relying on the May 27, 2025 CWG draft report entitled “Impact of Carbon Dioxide Emissions on the U.S. Climate” or the July 23, 2025 CWG report entitled “A Critical Review of Impacts of Greenhouse Gas Emissions on the U.S. Climate” for any aspect of this final action.

This is good news, since it leaves them with only a legal argument that for some reason the law is different now than it was when Mass. v. EPA was decided in 2007. That ruling forced the EPA to conduct the Endangerment finding in the first place, and still stands as legal precedent. The EPA argument now is that recent rulings (Loper-Bright and W.V.) from the Supreme Court mean that the original ruling can no longer be relied on. However, only the Supreme Court really has the power to overturn previous SC rulings and so the next set of lawsuits (in D.C. District Court) will likely find for the plaintiffs and possibly enjoin this ‘final’ rule. If this then goes to appeal to the SC, they would have to agree to hear it, and then folks would basically have to re-litigate the whole thing. Only lawyers are likely to gain from this.

Science will still play a role in this since a) the fact that CO₂ and the other five greenhouse gases (the Kyoto gases – CH4, N2O, CFCs, etc.) do endanger public health and welfare is now unchallenged, and b) EPA is now relying on a de minimus argument (which will likely also be challenged) about the impact of regulations on motor vehicles (which isn’t really a valid part of the endangerment finding) that comes from climate modeling. The CWG folks will likely not play any further role in any of this.

The ruling is long and legalistic, and so interested parties will need to take some time to digest what it says and what to do. As they say on Broadway, this one will run and run…