California on Thursday approved rules for a multibillion-dollar carbon market, in what proponents hope and detractors fear will be a turning point for the United States toward building a national program to address global warming.

After Congress failed to pass a climate change law last year, California is the vanguard of the nation’s effort to address global warming and its bid to build alternative energy and related industries.

California has mandated that a third of its electricity come from renewable sources like solar and wind. It is also encouraging “low carbon” auto fuels, like some biofuels and natural gas, and on Thursday approved rules for the carbon market.