It's only a preliminary injunction, but the ruling by a U.S. District judge out of Fresno waylays the state's effort to reduce its greenhouse gas emissions to 1990 levels by 2020. California's low-carbon fuel standard was found to discriminate against crude oil and corn ethanol producers that import fuel from out of state. From the WSJ:
The decision puts on hold a major portion of California's effort to cut greenhouse-gas emissions, at a time when the most-populous state's stance has taken on extra importance nationwide because of a stalemate in Washington over greenhouse-gas legislation. The ruling means that refiners and ethanol producers won't have to buy credits when importing oil and ethanol into California, as the regulations would have required in certain cases.
The California Air Resources Board asked the court to stay the preliminary injunction and said it would appeal the ruling. We should expect lots of litigation on this over the next few years.