Transportation is the largest source of planet-warming greenhouse gases in the United States today and the bulk of those emissions come from driving in our cities and suburbs.
By Nadja Popovich and Denise Lu, Oct. 10, 2019
Even as the United States has reduced carbon dioxide emissions from its electric grid, largely by switching from coal power to less-polluting natural gas, emissions from transportation have remained stubbornly high.
The bulk of those emissions, nearly 60 percent, come from the country’s 250 million passenger cars, S.U.V.s and pickup trucks, according to the Environmental Protection Agency. Freight trucks contribute an additional 23 percent.
Reducing emissions from driving has been a big challenge, said Conor Gately, who led the project mapping CO2 on America’s roads as a postdoctoral researcher at Boston University. Emissions dipped during the recession of the late 2000s, but have been ticking back up since 2013.
National fuel economy standards put in place under the Obama administration have helped temper the rise in automotive emissions because the rules require cars and trucks to use less gasoline per mile traveled. But even as vehicles have become more efficient, Americans, buoyed by a strong economy and low gas prices, have been driving more miles and buying more S.U.V.s and pickup trucks, which have lower gas mileage. Freight trucking is also on the rise.
The Trump administration is expected to finalize a rollback of efficiency standards for passenger vehicles this month, a move that could significantly increase future emissions from America’s cars and trucks.