In 2020, carbon dioxide was the biggest source of greenhouse gas emissions in the US, about 80%. The other 20% were from other greenhouse gases such as methane and nitrous oxide.
And in the US, the largest source of carbon dioxide emissions was from transportation. The transportation sector includes the movement of people or goods through vehicles such as passenger cars, trucks, and motorcycles, or through aircrafts, boats, railways, pipelines, or public mass transit systems. Burning fossil fuels such as gasoline or diesel accounted for about a third of all US carbon emissions and about a quarter of US greenhouse gas emissions.
