California Governor Jerry Brown issued an executive order on Wednesday to cut greenhouse gas emissions 40 percent by 2030, a move he said was necessary to combat the growing threat of climate change.
The targeted reduction was tied to 1990 levels and is "the most aggressive benchmark enacted by any government in North America to reduce dangerous carbon emissions," Brown said in a statement.
California operates the nation's largest carbon cap and trade system. The state sets an overall limit on carbon emissions and allows businesses to hand in tradeable permits to meet their obligations.
Achieving the new target will require reductions from sectors including industry, agriculture, energy and state and local governments, Brown said.
"I've set a very high bar, but it's a bar we must meet," Brown told a carbon market conference in downtown Los Angeles on Wednesday.
Brown said the new target will position California as a leader in combating climate change in the United States and internationally.
Brown said he has spoken to leaders in Oregon, Washington and Northeastern states about collaborating with California to cut their output of heat-trapping greenhouse gases. Those states could potentially link to California's carbon market in future years.
He said he has had similar discussions with leaders in the Canadian provinces of Quebec, British Columbia and Ontario, as well as in Germany, China and Mexico.
Quebec is already linked to the California market. Leaders in Ontario this month signaled their intention to join the program.
"This will be a local policy but it will be globally focused," Brown told reporters on the sidelines of the conference.
United Nations Secretary-General Ban Ki-moon welcomed the news and encouraged other states and cities around the world to also take action, U.N. spokesman Farhan Haq said.
"California's bold commitment to tackling climate change is a strong example to states and regions all over the world that they can join their national governments in taking ownership of this critical issue and in showing leadership," Haq said.
The plan for how California will achieve the 2030 target will be hammered out over the next year by the California Air Resources Board (ARB), which oversees the cap-and-trade program.
"With this bold action by the governor, California extends its leadership role and joins the community of states and nations that are committed to slash carbon pollution through 2030 and beyond," said Mary Nichols, chair of the ARB.