In July 1943, at the height of World War II, toxic fumes were so thick in parts of Los Angeles that residents believed they were facing a gas attack from Japan. Soon after, blame fell on an industrial plant owned by Southern California Gas Co. — a theory that was abandoned when the plant shut temporarily but fumes still blanketed the city and reports of respiratory illnesses and eye irritation continued. Eventually, Caltech chemist Arie Haagen-Smit figured out that what came to be known as smog was mostly ozone created when sunlight hit exhaust from motor vehicles and oil refineries.

Related: Trump’s EPA: Debate over vehicle emission laws begins

The Golden State has led the world in responding to air pollution ever since. Haagen-Smit’s research prompted automakers to install the first vehicle emissions controls and inspired Gov. Ronald Reagan to name the chemist as the first head of the California Air Resources Board in 1968. Two years later, when Congress followed California’s lead by enacting the 1970 Clean Air Act, lawmakers acknowledged the state’s severe air pollution problems and locked its pioneering regulatory response in history by allowing state officials to enforce stronger air pollution standards than the federal government’s. This deference has been key to the state becoming an immensely positive influence on the modern environmental movement — and thus on the economy and on how people live. “California’s policies drive technological change in the transportation sector, not just nationally, but internationally,” the Yale Environment 360 magazine noted.

The Trump administration seeks to imperil this history by ending California’s leadership on vehicle emissions and mileage standards. Next week, EPA Secretary Scott Pruitt is expected to propose dropping Obama administration rules issued in 2012 that force automakers to nearly double the average miles per gallon of new cars and trucks by 2025. Pruitt is also prepared to pursue a court fight, at the urging of automakers, to block California from continuing to set its own stricter rules for vehicles, which are now followed by 12 other states.


California Attorney General Xavier Becerra has filed 28 lawsuits against the Trump administration — a mind-boggling two a month on average — and his mixed success so far suggests some of his efforts are more political statements than surefire winners. But if Becerra sues the administration over its attempt to force California to weaken its vehicle emissions and fuel standards, that won’t be a political fight. It will be a fight to stave off disaster. Seventy years ago, air pollution seemed a local problem. Now there is a scientific consensus that greenhouse gases (including ozone) released as a result of human activity are warming the entire planet with potentially catastrophic results. That is why The San Diego Union-Tribune Editorial Board called President Donald Trump’s move last year to withdraw from the Paris climate accord the “worst decision of his life.” A bid by his administration to keep California from continuing its global environmental leadership would be similarly atrocious.

“We’ve got the scientists, we’ve got the lawyers, and we’re ready to fight,” Gov. Jerry Brown told a meeting of the American Geophysical Union a month after Trump’s election, anticipating a conflict over climate change. “And we will persevere.”

Believers in science must hope Brown is right.

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