Carbon-neutral California: Governor signs a historic climate law and adds a bold executive order

The new law requires the world’s fifth largest economy to generate 100 percent of its electricity from carbon-free sources by the end of 2045, marking one of the world's most ambitious climate policies (see “California advances an ambitious climate policy that should be a model for the world”).

There’s more: California governor Jerry Brown went a significant step further on Monday, signing an executive order directing state agencies to figure out how to make the entire economy carbon neutral in that same time frame. That would require transforming not just California’s electricity sector but transportation, manufacturing, and more. In addition, the order sets a goal of maintaining “net negative emissions” beyond 2045, which means using plants or technology to draw carbon dioxide out of the atmosphere, and reuse or store it some manner (see “Maybe we can afford to suck CO₂ out of the sky after all”).

An important marker: It’s unclear how enforceable or achievable the executive order is at this point. There are still major technological hurdles to cleaning up shipping, aviation, long-haul trucking, or other industries, and negative-emissions technologies haven’t been shown to work on a large scale yet (see “We still have no idea how to eliminate more than a quarter of energy emissions”).

“An executive order from an outgoing governor is not the same thing as a law,” noted Michael Wara, director of the climate and energy policy program at the Stanford Woods Institute for the Environment, in a tweet. “I would celebrate the law and view the EO as an important marker of where the state should aim.”

A test bed: Some observers believe the clean electricity measure is now the most important climate law on the books in the United States, given the strict limits, the size of California’s economy, and the measure’s technological flexibility. As MIT Technology Review previously reported, the state is, “acting as a test bed for what’s technically achievable, providing a massive market for the rollout of clean-energy technologies and building a body of knowledge that other states and nations can leverage.”