Bottom Line on Regulating Greenhouse Gases Under The Clean Air Act

Following a 2007 Supreme Court ruling and a 2009 EPA finding that greenhouse gases (GHGs) endanger public health and welfare, the EPA is positioned to regulate GHGs under the Clean Air Act. Potential regulatory paths include emission performance standards for motor vehicles and performance or technology standards for stationary sources like power plants and factories. While such regulations may increase production costs for some manufacturers, they could lower consumer costs through improved fuel and electricity efficiency. The document notes that EPA action could overlap or conflict with future congressional legislation unless statutory authority is clearly defined.

• The EPA's authority to regulate greenhouse gases (GHGs) stems from a 2007 Supreme Court decision in Massachusetts v. EPA, which determined that GHGs are classified as air pollutants under the Clean Air Act. This led to an April 2009 'endangerment finding' stating that GHG emissions threaten public health and welfare, and a 'cause or contribute finding' specifically linking motor vehicle emissions to climate change.
• The EPA has several potential regulatory paths depending on the source of emissions. For mobile sources, it may issue emission performance standards (e.g., grams of CO2/mile). For stationary sources like factories and power plants, it could use performance standards, technology standards requiring specific control equipment, or a cap-and-trade program, though the latter may be limited by the Clean Air Act's framework.
• Regulation of GHGs would likely result in mixed economic impacts for businesses. While manufacturers of regulated products might face higher production costs, which could increase consumer prices, consumers may see lower overall costs due to reduced fuel and electricity usage. Additionally, companies producing products with superior GHG performance could gain a competitive advantage.
• There is a risk of redundancy or conflict between EPA regulations and future legislation from Congress. To prevent this, the document suggests that new legislation must explicitly clarify the boundary between existing Clean Air Act authority and new statutory authority.

APA

World Resources Institute (n.d.). Bottom Line on Regulating Greenhouse Gases Under The Clean Air Act. https://www.wri.org/research/bottom-line-regulating-greenhouse-gases-under-clean-air-act

Chicago

World Resources Institute. Bottom Line on Regulating Greenhouse Gases Under The Clean Air Act. n.d. https://www.wri.org/research/bottom-line-regulating-greenhouse-gases-under-clean-air-act.

Wikipedia

{{cite report |author=World Resources Institute |title=Bottom Line on Regulating Greenhouse Gases Under The Clean Air Act |url=https://www.wri.org/research/bottom-line-regulating-greenhouse-gases-under-clean-air-act |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{worldresourcesinstitutendbottom, author = {{World Resources Institute}}, title = {{Bottom Line on Regulating Greenhouse Gases Under The Clean Air Act}}, institution = {World Resources Institute}, url = {https://www.wri.org/research/bottom-line-regulating-greenhouse-gases-under-clean-air-act}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }