https://phys.org/news/2018-07-california-climate-goal-earlybut-biggest.html

Further complicating matters is a Trump administration plan to weaken fuel economy standards and revoke California's power to set its own, stricter rules—a move that could cause vehicle emissions to rise even more.

The uneven progress shows the big challenges that loom as California advances toward its more ambitious goal: slashing planet-warming greenhouse gas emissions another 40 percent by 2030.