According to new EPA data, transportation became the largest source of greenhouse gas emissions in the United States in 2017 after emissions from electricity generation continued to decline.
Of total greenhouse gas emissions, the majority are due to CO2 emissions. CO2 was responsible for 82% of all greenhouse gas emissions in 2017. Transportation accounted for 37% of total CO2 emissions. According to the report, the largest sources of transportation-related CO2 emissions were passenger cars (41%), medium- and heavy-duty trucks (24%), and light-duty trucks (17%). Commercial air travel accounted for a relatively small share, at 7% of transportation-related emissions.
An increase in travel was the reason transportation eclipsed electricity to be the largest source of CO2 emissions. The total number of miles driven by passenger cars and trucks increased 46% from 1990 to 2017.
