Between 1990 and 2019, annual transportation sector CO2 emissions increased by roughly 80 percent to a record high of 8.25 billion metric tons (GtCO2). Although global transportation emissions plummeted 12 percent in 2020 due to the outbreak of COVID-19, they are expected to have rebounded in 2021.
Where are transportation emissions highest?The U.S. is the biggest contributor to global transportation emissions by far. U.S. transportation-related emissions totaled 1.56 GtCO2 in 2020. Pre-pandemic, U.S. transportation emissions were averaging more than 1.7 GtCO2 a year. Economic growth in China has seen transportation emissions there soar over the past two decades, rising from less than 300 MtCO2 in 2000 to 966 MtCO2 in 2020. China now has the second-highest annual transportation emissions worldwide and was one of the few countries where they transportation emissions increased in 2020.
Despite its overall emissions, China’s transportation emissions per capita are far lower than in many other countries, at 0.68 metric tons per person. In comparison, the average Canadian emitted 4.19 metric tons of CO2 from transportation, which was the second-highest behind only the U.S.
Most polluting transportation modesRoad vehicles are the leading source of transportation emissions worldwide. Passenger cars alone accounted for 41 percent of global transportation-related CO2 emissions in 2020. This is somewhat unsurprising, given there are thought to be more than a billion cars on the road worldwide. Increased purchasing power has seen passenger car CO2 emissions almost double since 2000, rising from 2.2 GtCO2 to 3.2 GtCO2 in 2019. Road-freight vehicles are major polluters too. In 2020, just 64 million heavy-duty and medium-duty trucks emitted approximately 1.8 billion MtCO2 worldwide
Meanwhile, aviation accounts for two percent of global GHG emissions. On average, domestic flights have the most significant carbon footprint of any mode of transportation. Aside from walking and cycling, the most sustainable way to travel is by rail.