LegiStorm

Summary:

This report discusses EPA's authority to regulate greenhouse gas (GHG) emissions as it pertains to mobile sources, including cars, trucks, aircraft, ships, locomotives, nonroad vehicles and engines, and their fuels. The Supreme Court held in 2007 that the Clean Air Act (CAA) authorizes the agency to address GHG emissions. The key to using this CAA authority was for the EPA Administrator to find that GHG emissions endanger public health or welfare, a step taken in December 2009. Under the Trump Administration, it is unclear whether this authority will be put to further use. Other questions concern what steps EPA and Congress may take with regard to already promulgated—but not yet implemented—standards for GHG emissions from cars and trucks. In principle, the auto manufacturing and trucking industries have been supportive of EPA's GHG regulations, in part because of concerns that states would implement a patchwork of standards in the absence of federal action. As the standards have been implemented, however, industry concerns have arisen regarding a lack of harmonization between EPA's GHG standards, fuel efficiency (CAFE) standards administered by the National Highway Traffic Safety Administration (NHTSA), and related California GHG and fuel efficiency programs. One issue concerns the Model Year (MY) 2017-2025 light-duty vehicle regulations. Under these standards, GHG emissions from new light-duty vehicles (i.e., cars, SUVs, crossovers, minivans, and most pickup trucks) will be reduced about 50% compared to 2010 levels, and average fuel economy will rise to nearly 50 miles per gallon by 2025. When EPA and NHTSA promulgated the standards in 2012, EPA committed to a Midterm Evaluation (MTE) of the 2022-2025 portion of the GHG standards. This evaluation was completed on January 12, 2017, with EPA deciding to maintain the standards as promulgated. Given industry concerns about the standards, there is speculation as to whether the Administration will reconsider the MTE decision. A second issue concerns GHG emission and fuel economy standards for medium- and heavy-duty trucks. EPA and NHTSA promulgated a second phase of these standards on October 25, 2016, covering trucks and engines beginning with the 2021 model year and truck trailers beginning in 2018. These standards could be reconsidered by the two agencies, or Congress could review them under the Congressional Review Act. GHG emissions are directly related to fuel combustion. In order to reduce GHG emissions, EPA expects the standards to increase fuel efficiency, lowering oil consumption by up to 2 billion barrels over the lifetime of 2018-2029 trucks and saving vehicle owners about $170 billion in fuel costs as a result. In general, the truck standards – with the exception of the portion dealing with trailers—have been well-received, leaving in question whether general opposition to GHG rules will shape Congress's and the new Administration's reaction to the rules more than the views of the affected industries. A third potential issue concerns GHG emission standards for aircraft. In October 2016, the International Civil Aviation Organization (ICAO) agreed on international carbon dioxide (CO2) emission standards for aircraft, beginning in 2020, and on a system for offsetting future CO2 emissions from aviation. The emission standards would be implemented in the United States by EPA regulations issued under the CAA. U.S. airlines and aircraft manufacturers participated in the ICAO negotiations and have been supportive of the resulting agreements; whether EPA actions to implement them would run contrary to the President's and the Administration's broader views on regulation and climate change is unclear. In addition to a discussion of these three issues, this report provides background on GHG emissions from other mobile sources, including ships, nonroad vehicles and engines, locomotives, and fuels.