The US transport sector is emitting more carbon dioxide than power generation for the first time since the 1970s.
That was revealed by the Energy Information Administration on Thursday.
A shift away from burning coal to cleaner natural gas and renewable sources has seen power sector emissions trend downwards since 2007.
Yet while cars have got more efficient over the same period, the impact has – so far – been marginal. In 2012 the Barack Obama administration introduced emission standards mandating the doubling of vehicle fuel efficiency by 2025.