California will extend its landmark climate change legislation to 2030, a move that climate specialists say solidifies the state’s role as a leader in the effort to curb heat-trapping emissions. Lawmakers have passed, and Gov. Jerry Brown has promised to sign, bills requiring the state to reduce its greenhouse gas emissions to 40 percent below 1990 levels. Though the governor had already set a similar goal in an executive order, the legislation will lock the goals into law. The ambitious plan targets both power plants and vehicle emissions. “This is a real commitment backed up by real power,” Mr. Brown said, calling it a milestone in the state’s climate change efforts. He criticized the oil industry , which fought the legislation, as “Trump-inspired acolytes.” “The effort to decarbonize our economy in California and in our country is a tough hill, and there is opposition,” he said. […]