Transportation sector CO₂ emissions in the U.S. 1980-2021, by state

Texas and California have consistently been the two biggest transportation-related carbon polluters in the U.S. In 2021, they emitted 215 and 179 million metric tons of carbon dioxide (MtCO₂), respectively. Combined, these two states – the most populous in the U.S. – account for almost a quarter of total U.S. transportation CO₂ emissions.

Changes in U.S. state transportation emissions

As of 2021, 32 U.S. states had observed overall transportation-related emission reductions when compared to 2005 levels. The state with the largest emissions reductions during this period was New Jersey, at almost 40 percent. In contrast, Texas’ transportation emissions grew by more than 10 percent over this timespan.

Transportation’s share of emissions

In 2021, transportation accounted for at least 50 percent of total energy-related CO₂ emissions in 10 U.S. states. In California, this figure stood at 55. Meanwhile, transportation accounted for 32 percent of energy-related CO₂ emissions in Texas, despite it being the biggest transportation-related polluter in the U.S.