Transportation is likely to surpass the electricity sector in 2016 as the largest source of carbon dioxide emissions in the United States, according to a new analysis of government data.

In 2008, the global financial crisis caused widespread declines in energy use. In the U.S., that coincided with the early stages of a large-scale shift away from coal toward cleaner-burning natural gas as a way to generate electricity. As a result, carbon dioxide emissions from the electricity sector have continued to decline from their 2007 peak, even as the economy has resumed growing.

The trend line for the transportation sector is less encouraging. Transportation emissions have begun rising as the economy rebounds. John DeCicco at the University of Michigan Energy Institute, who wrote the study, attributes the rebound we’ve seen during the past four years to straightforward causes: economic recovery and more affordable fuel prices. Vehicle sales numbers have been rising for several years, in particular for trucks and SUVs, and people are traveling more miles.

The trends have significant implications for the country’s energy policy. President Barack Obama’s Clean Power Plan will help ensure that emissions from generating electricity continue to fall in the coming years, and there are plenty of alternatives to coal-fired power plants. As for transportation, gasoline and diesel figure to keep dominating the market for decades because electric cars, the alternative, have been slow to take off. Federal laws designed to increase fuel efficiency and reduce tailpipe emissions will only serve to offset increasing travel demand, DeCicco says.

That means that one of our best hopes for fighting climate change over the next few years will be the return of high-priced gas.