Initiated in 2012, the California Cap-and-Trade Program began its compliance obligation on 1 January 2013. California has been part of the Western Climate Initiative (WCI) since 2007 and formally linked its system with Québec's on 1 January 2014. In July 2017, California passed legislation extending the cap-and-trade program to 2030.
The cap-and-trade program covers sources responsible for approximately 85% of California’s GHG emissions. In 2016, California passed legislation to reduce emissions by 40% compared to 1990 levels by 2030.