It is much lower than you think

Consider the following claims:

[E]missions are increasing the concentration of CO2 in the atmosphere through a complex and variable carbon cycle, where some portion of the additional CO2 persists in the atmosphere for centuries. . . Carbon dioxide also acts as a greenhouse gas, exerting a warming influence on climate and weather . . .

Today, I explain why the acceptance of just these claims provides a sufficient basis under the U.S. Clean Air Act (CAA) to find that greenhouse gas emissions (GHGs) endanger public health or welfare. The quote above comes from the executive summary of the much-discussed report of the Department of Energy’s Climate Working Group (DOE CWG). Roger Pielke Jr. substack- The Honest Brocker has the story.

“Endangerment” is a legal concept, not scientific, which can be traced back to 1955 in federal legislation regulating air pollution.1 The relevant language of the CAA is shown below, from Section 202(a), with the endangerment clause highlighted.

The concept of “endangerment” under the CAA has been considered explicitly by the courts, which concluded that “endangerment” means “risk of harm”:

The meaning of “endanger” is not disputed. Case law and dictionary definition agree that endanger means something less than actual harm. When one is endangered, harm is threatened; no actual injury need ever occur. Thus, for example, a town may be “endangered” by a threatening plague or hurricane and yet emerge from the danger completely unscathed. A statute allowing for regulation in the face of danger is, necessarily, a precautionary statute. Regulatory action may be taken before the threatened harm occurs; indeed, the very existence of such precautionary legislation would seem to demand that regulatory action precede, and, optimally, prevent, the perceived threat.2

In the 2009 EPA Endangerment Finding, the EPA administrator characterized the finding explicitly in terms of “risk of harm,”3 with the nature of risk and of harm considered together. The EPA administrator found,

. . . that six greenhouse gases taken in combination endanger both the public health and the public welfare of current and future generations.

The EPA administrator explained:

The Administrator reached her determination by considering both observed and projected effects of greenhouse gases in the atmosphere, their effect on climate, and the public health and welfare risks and impacts associated with such climate change. The Administrator’s assessment focused on public health and public welfare impacts within the United States. She also examined the evidence with respect to impacts in other world regions, and she concluded that these impacts strengthen the case for endangerment to public health and welfare because impacts in other world regions can in turn adversely affect the United States.

The CAA offers no standards of risk or harm necessary to constitute a finding of endangerment, and the Supreme Court has ruled that relatively small amounts of pollution are not exempt from regulation.4

Read the full story here.