Breakdown of CO2 emissions in the transportation sector worldwide 2020, by subsector

The global transportation sector is a major polluter and in 2020 produced approximately 7.3 billion metric tons of carbon dioxide (CO2) emissions. Passenger cars were the biggest source of emissions that year, accounting for 41 percent of global transportation emissions.

Road transportation emissions

In recent decades, global CO2 emissions from passenger cars have increased and peaked at 3.2 billion metric tons in 2019. Car emissions fell in 2020, but this was only due to the COVID-19 pandemic. Medium and heavy trucks are the second- largest polluters, accounting for 22 percent of transportation emissions. Although this was half the emissions of passenger cars, there are considerably fewer trucks on the road, showing just how polluting global road freight is. In 2020, heavy-duty truck CO2 emissions totaled almost two billion metric tons.

Where are transportation emissions highest?

The United States is by far the largest producer of transportation emissions worldwide. Between 1975 and 2007, U.S. transportation sector CO2 emissions increased 56 percent to over two billion metric tons. Although emissions began to decline in the following years, they increased again to reach 1.9 billion metric tons in 2019. Much like the rest of the world, COVID-19 impacted U.S. emissions, causing them to plummet to almost 300 million metric tons in 2020.