EPA to Regulate CO2 Emissions from Aircraft

by Marlo Lewis on September 16, 2014

in Blog

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EPA plans to propose and finalize regulations establishing first-ever carbon dioxide (CO2) emission standards for jet aircraft. The agency recently submitted an Information Paper to the UN’s International Civil Aviation Organization (ICAO) setting out a regulatory timeline. Once again, the Obama administration reads the Clean Air Act (CAA) to require a climate policy never intended or approved by Congress, and undertakes to negotiate an international agreement that likely would not survive a Senate vote on ratification.

A product of creeping Kyotoism, the yet-to-be-proposed rule has been gestating since 2007. From EPA’s Information Paper:

The U.S./EPA is initiating the rulemaking process in response to a petition the U.S./EPA received in December 2007, which requested that U.S./EPA make an endangerment finding for aircraft GHGs [greenhouse gases] and regulate these emissions under §231 of the Clean Air Act (CAA). Petitioner filed a lawsuit in 2010 on this matter, and the D.C. District Court in 2012 ruled that the CAA required U.S./EPA to make a final determination on whether aircraft GHG emissions cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare. U.S./EPA is now moving forward to make a determination regarding aircraft GHG emissions.

CAA §231 requires EPA to establish emission standards for aircraft if the agency determines that “emission of any air pollutant from any aircraft . . . causes, or contributes to, air pollution which may reasonably be anticipated to endanger public health or welfare.” That EPA will make a positive finding of endangerment is a foregone conclusion.

As the Information Paper notes, EPA already determined in December 2009 that greenhouse gas-related “air pollution” from new motor vehicles endangers public health and welfare. Through that action, EPA empowered itself to set de facto fuel economy standards* under CAA §202, poaching regulatory authority delegated by Congress to another agency (the National Highway Traffic Safety Administration) under a separate statute (the Energy Policy and Conservation Act). So EPA will undoubtedly determine that “air pollution” from aircraft GHG emissions warrants a further expansion of the agency’s regulatory power.

The main difference this time round is that EPA will be setting quasi-fuel economy standards for aircraft, even though no existing statute authorizes any agency to prescribe such standards.

The scientific case for endangerment is weaker today than it was five years ago (see, e.g., here, here, here, here, and here). However, courts are deferential to agency expertise and typically decline to adjudicate scientific controversies.

Courts may, however, be more open to scientific pushback if they question the coherence of EPA’s basic reasoning. What follows is a rumination on EPA’s attempt to define “carbon pollution” in its seminal December 2009 endangerment determination. EPA’s definition, in my view, is a conceptual muddle.

Does EPA Coherently Define the “Air Pollution” Related to Greenhouse Gases?

An endangerment finding is a “judgment” that emissions of a particular type or description “cause or contribute to air pollution. . . which may reasonably be anticipated to endanger public health or welfare” [CAA §§ 108(a)202(a), 231(a)]EPA is to assess the dangerousness not of the emissions per se but of “air pollution” related to the emissions.

Logically, this means EPA’s first order of business is to identify or define the “air pollution” at issue. However, defining “air pollution” related to GHGs is difficult, because CO2, the principal GHG emitted by industrial sources, is an essential building block of the planetary food chain, and does not impair air quality at multiple times ambient concentrations.

EPA defines the air pollution related to GHGs as the “elevated concentration of well-mixed greenhouse gases in the atmosphere” (74 FR 66536). This approach clashes with “air pollution” as that term applies to other pollutants regulated under the CAA. For criteria (air quality) and toxic (hazardous) air pollutants, for example, concentration determines whether such substances endanger public health and welfare, it does not determine whether their presence in the atmosphere constitutes air pollution.

Consider particulate matter (PM). Each particle pollutes the air to some extent, even if particles might pose no health risk at very low concentrations. With regard to PM pollution, the fewer the particles the cleaner the air. In completely clean (pollution-free) air, PM would not exist in any concentration.

Similarly, clinical studies of the effects of ozone (O3) on lung function proceed by adding varying amounts of ozone to “clean filtered air” (EPA, Health Risk and Exposure Report for Ozone, Final Report, August 2014, 6-17). Even though natural background air in many places contains ozone, completely “clean” ambient air is ozone-free.

Carbon dioxide does not fit this template. Removing all CO2 from the air would not make it cleaner (it would, rather, bring an end to nearly all life on planet Earth!). Conversely, increasing CO2 concentrations from 280 molecules per 100,000 (roughly the pre-industrial level) to 400 molecules per 100,000 (roughly today’s level) does not make the air less clean. Yet EPA’s Endangerment Rule implies that although 280 molecules per 100,000 is not air pollution, every additional CO2 molecule is air pollution.

The Endangerment Rule mixes up two distinct questions: What is the air pollution related to the
emissions of concern? At what concentration does such air pollution endanger public health or welfare?

EPA might respond that, per the Supreme Court’s ruling in Massachusetts v. EPA, an “air pollutant” is anything “emitted,” and emissions account for the “elevated concentration” of atmospheric CO2. In other words, natural or pre-industrial levels of CO2 are not air pollution; only the increment added by fossil-fuel emissions is air pollution. But if that is EPA’s reasoning, it is not grounded in the statute. CAA §302(g) neither states nor implies that “air pollution” comes only from Man and never from Nature.

CAA §302(g) does not limit “air pollutants” to “emitted” substances. An “air pollution agent” that “otherwise enters” the ambient air is also an “air pollutant.” Particles, for example, pollute the air regardless of whether they come from volcanoes, dust storms, forest fires, or fossil-fuel combustion. Most atmospheric CO2 comes from natural sources — oceans, forests, soils, and volcanoes. Thus, if we accept the Massachusetts holding that anything emitted into or otherwise entering the ambient air is an “air pollutant,” it follows that pre-industrial concentrations of CO2 are also “air pollution.”

The incoherence of EPA’s definition of the “air pollution” related to GHGs is of more than academic interest. The Massachusetts Court held that EPA does not have to make an endangerment finding if the agency can provide a “reasonable explanation” why it cannot or will not make such a determination (Mass v. EPA, Slip Opinion, p. 5). 

To repeat, an endangerment finding is a judgment not about emissions as such but about the related “air pollution.” If EPA cannot coherently define “air pollution related to GHGs,” then it lacks the requisite subject matter upon which to make an endangerment finding. In short, EPA had to distort the meaning of “air pollution” to fit CO2 into the Clean Air Act’s regulatory framework. 

This conclusion also sheds light on why EPA and its allies continually use the term “carbon pollution.” The rhetorical function of “carbon pollution” is not just to evoke fear and loathing of fossil fuels. Its purpose is also to make EPA’s repeated breach of the separation of powers look like ordinary exercises of the agency’s statutory authority to clean the air.   

* No commercially-available technologies exist to capture or filter out CO2 emissions from cars, trucks, marine vessels, or aircraft. Consequently, the only way to decrease grams of CO2 per mile is to reduce fuel consumption per mile — that is, increase fuel economy (75 FR 25424, 25327). 


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