Last week California Gov. Jerry Brown made headlines when he announced that his state would pursue the most aggressive greenhouse gas emissions cuts in the nation. The new goal—to reduce emissions 40 percent below 1990 levels by 2030—is an interim step meant to help achieve a final goal set by Brown's predecessor, Arnold Schwarzenegger, of an 80 percent reduction by 2050. Exact details on how the new target will be achieved haven't yet been released, but it will likely include a combination of new clean energy mandates and pollution reduction rules for power companies, as well as incentives for electric vehicles.