Between 2005 and 2016, carbon dioxide emissions in California decreased 5.8%, compared to an average decrease of 12.4% for the entire country. This disparity is likely due to California's large transportation sector.
Transportation-related factors account for over 40% of greenhouse gas emissions in California. More than half of those emissions come from passenger vehicles. In 2017, vehicle ownership rates and vehicle miles travelled both hit new highs, likely due to California’s strong economy and a shortage of housing forcing more people to commute longer distances.
Per-capita, California's emissions in 2016 were the second-lowest in the U.S., beaten only by New York among the 50 states. In absolute terms, the populous state was the second-highest, with total emissions by no. 1 Texas some 80% higher.