The U.S. transportation sector is responsible for about a third of our country’s climate-damaging emissions. In California transportation is the leading source of greenhouse gas pollution, accounting for about 40% of the state’s emissions. Fossil-fueled transportation emissions also create smog, soot and other harmful air pollution.

Reducing transportation emissions is one of the most vital steps in fighting the climate emergency, and solutions to the transportation problem are already available. Our nation needs to shift away from fossil fuel-powered vehicle dependence and toward zero emissions in all transport sectors.


As a member of the large plaintiff group in Massachusetts v. EPA, we celebrated the Supreme Court’s April 2007 decision declaring CO2 a pollutant under the Clean Air Act, which meant the Environmental Protection Agency has the authority to regulate greenhouse gas emissions from new motor vehicles under the Act. And in November 2007, the Center and our allies prevailed in CBD v. NHTSA, a major lawsuit filed against the Department of Transportation for failing to properly account for greenhouse gas emissions when setting unreasonably low national fuel economy standards. 

In 2012 the Obama administration finalized greenhouse gas and mileage standards that mandated reaching maximum gas mileage of 54.5 miles per gallon by 2025. But cars and trucks are commercially available today that meet and exceed this standard, including a wide variety zero emission vehicles, and technology for these vehicles is rapidly advancing while costs are declining.

Nevertheless the Trump administration finalized a rule to revoke California’s ability to set its own stringent greenhouse gas emissions standards (along with the ability of other states to follow California’s lead), and proposes to roll back the existing, already insufficient standards adopted by the previous administration. We and our allies are fighting back against these disastrous proposals in court.

But beyond preserving our existing car standards, we need to phase out vehicles with internal combustion engines within the next decade to meet the demands of the climate emergency. Other countries, including Norway, Denmark, Sweden, the Netherlands, Iceland and Germany, have already pledged to ban the sale of new fossil-fuel cars by 2030. We’re pushing California and the federal EPA to expand renewable electric infrastructure and establish increasingly stringent emissions standards in cars, pickups, buses and trucks, which would prohibit the sale of any new fossil fuel cars no later than 2030. 


Cars aren’t the only vehicles that pollute — airplanes, ships and trains produce a large portion of the world’s greenhouse gas emissions.

Aircraft are the third-largest source of greenhouse gas pollution from the U.S. transportation sector and account for approximately 10% of U.S. transportation emissions — they also emit nitrogen oxides other than nitrous oxide, causing warming when emitted at high elevation. And the emissions from domestic aviation are increasing at an alarming rate — 17% since 1990. In 2007 the Center and several allies petitioned the U.S. EPA to set standards limiting greenhouse gas emissions from aircraft under the Clean Air Act.

Spurred by subsequent litigation, in 2016, the EPA found that these emissions endanger public health and welfare. But it has still not promulgated any standards. We're urging the next administration’s EPA to set stringent, technology-forcing emissions standards for aircraft — including for supersonic airplanes, which are project to burn five to seven times more fuel per passenger than typical planes.
Ships, besides releasing almost 3% of the world’s CO2, are a main source of nitrous oxide and black carbon (soot). With international trade expected to increase in the coming years, emissions from ships and boats may increase by as much as 250% by 2050. Yet fully electric cargo and passenger ferries are already in operation in some countries. In 2007 we and our allies petitioned the U.S. EPA to set greenhouse gas limits for ships, and we’re urging the administration under the next EPA to move forward with setting standards.

Greenhouse gas emissions from diesel-engine trains contribute two percent of U.S. transport emissions, and have increased seven percent since 1990, despite the widespread availability of more efficient fully electrified rail. The United States has an urgent need to modernize its rail network and eliminate diesel engines. In 2010 we and our allies petitioned the U.S. EPA to set emission standards for greenhouse gases and black carbon emissions, and will be pushing the next EPA to set emissions standards for trains to ensure a transition to 100% clean, renewably electric power by no later than 2030.

Photo courtesy of Wikimedia Commons/Steevven