Accounting for the Global Nature of Greenhouse Gas Pollution in the Findings

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In this draft proposal, EPA finds under Clean Air Act (CAA) section 202(a) that (1) “air pollution” in the form of the global mix of six greenhouse gases (or the GHGs) may be reasonably anticipated to endanger public health and welfare (the endangerment finding); and (2) emissions of an “air pollutant” in the form of the global mix of the GHGs from new motor vehicles or motor vehicle engines cause or contribute to that air pollution (the contribution finding).

The agency characterizes the “global” nature of the GHG emissions and concentrations (page 16), notes the effects of GHG emissions globally in making the endangerment finding (page 29), and assesses the contribution of the GHGs emitted by section 202(a) sources as a percentage of global emissions (page 36). The proposal appears to assume, but does not explicitly discuss why (or solicit comment on whether) these are relevant legal inquiries under section 202(a) the Clean Air Act. This is virtually certain to be a subject of public comment; and we recommend that EPA directly address this matter in the proposal.

EPA also factors international considerations into the endangerment and contribution findings differently. On page 29, the agency states: “The Administrator judges that impacts to public health and welfare occurring within the U.S. alone warrant her proposed endangerment finding.” On page 36, however, EPA bases its finding on the “significance” of the GHG emissions from section 202(a) sources for purposes of the contribution finding in part on their global contribution:

It is the Administrator’s judgment that the collective GHG emissions from section 202(a) source categories are significant, whether the comparison is global (over 4 percent of total GHG emissions) or domestic (24 percent of total GHG emissions). The Administrator believes that consideration of the global context is important for the cause or contribute test but that the analysis should not solely consider the global context.

It is unclear from the proposal why a difference in treatment of the two findings is necessary or appropriate. Because the Administrator regards the domestic contribution comparison in itself to be significant, it may be simpler (and less open to challenge) to base the contribution finding solely on domestic considerations. (This would not foreclose a discussion of global contribution, provided, as requested above, it is made clear how relevant this is under section 202(a)).

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