California is once again at the epicenter of America’s climate policy battle, as Governor Gavin Newsom and his administration double down on environmental commitments in the face of mounting federal opposition. On September 22, 2025, Newsom sent a forceful letter to the U.S. Environmental Protection Agency (EPA), lambasting the Trump administration’s proposed rollback of national climate and clean air protections. The governor’s message was unequivocal: weakening these standards would not only stall progress but actively worsen the climate crisis, threatening both public health and the state’s ambitious emissions goals.
“California has demonstrated that ambitious standards and innovation go hand in hand,” Newsom wrote in his letter to the EPA, according to POLITICO. “Rolling back these protections would not only stall progress, it would actively worsen the climate crisis and the burden of pollution on our communities.”
This confrontation comes at a pivotal moment. The Trump administration’s EPA is pushing to reverse the long-standing “endangerment finding,” a legal and scientific determination that greenhouse gases threaten public health. This finding has underpinned nearly all federal efforts to curb planet-warming emissions from cars, trucks, and industry. Newsom’s formal comment to the EPA minced no words, describing the proposal as “negligence,” “unlawful,” and “a betrayal of the very mission entrusted to you.”
“The Clean Air Act could not be clearer: EPA has an affirmative duty to protect public health and welfare from air pollutants, including greenhouse gases,” Newsom wrote. “You are now proposing to ignore binding law, overwhelming science, and lived reality. That is not discretion — it is negligence. It is unlawful. It will cause great harm to the American people.”
The governor’s letter, sent on the eve of his trip to New York for Climate Week, highlighted the stakes for Californians. Wildfires, fueled by rising temperatures, have killed hundreds, destroyed entire communities, and caused tens of billions of dollars in damages. Extreme heat, now the deadliest climate impact in the state, claims more lives annually than wildfires and floods combined. Drought has battered California’s agriculture, costing billions and threatening food security nationwide. In recent years, climate-driven floods have inflicted an estimated $5 billion in damages on families and businesses.
The national picture is just as alarming. In 2023 alone, the United States endured 28 separate climate-driven weather disasters, each exceeding $1 billion in damages—a record high—claiming over 400 lives and causing $92 billion in losses, according to Newsom’s comment. Yet, the EPA’s proposal suggests that climate change no longer endangers Americans, a notion Newsom called “an insult.”
California, however, is not standing idly by. The state continues to leverage its authority under the Clean Air Act to set stricter emissions standards than those imposed nationally, often setting the pace for the rest of the country. Even as federal standards face rollback, California is expanding zero-emission vehicle requirements for manufacturers, funding pilot programs to accelerate clean transportation in heavy-duty fleets, and collaborating with utilities and private partners to build out EV charging corridors.
Yet, the state is also adapting its approach in light of changing federal policies and economic realities. Earlier this year, California officials floated the idea of creating a state-level supplement to the federal $7,500 electric vehicle (EV) tax credit. However, after careful consideration, the plan was shelved due to concerns about consumer confusion and potential strain on the state budget. Instead, California is focusing on investments in charging infrastructure and targeted rebates for low- and moderate-income households, aiming to keep the momentum for EV adoption alive without overextending state resources.
Transportation remains the largest source of greenhouse gas emissions in California, making the transition to zero-emission vehicles central to the state’s climate strategy. Despite stepping back from the state-level EV tax credit, officials insist that California’s broader efforts to build a robust market for clean vehicles are still on track.
At the same time, California’s climate leadership is delivering tangible results. Since 2000, the state’s greenhouse gas emissions have dropped by 20%, even as its GDP soared by 78%, cementing California’s status as the world’s fourth largest economy. In 2023, California was powered by two-thirds clean energy—the highest share for any large economy globally—and ran on 100% clean electricity for parts of nearly every day. Battery storage has exploded under Newsom’s watch, increasing by over 1,900% to more than 15,000 megawatts, with more than 25,000 megawatts of new resources added to the grid.
But California’s climate policy is not without its challenges and internal debates. On the same day as Newsom’s EPA letter, he announced the appointment of Lauren Sanchez—his 36-year-old senior climate adviser and a former Biden administration official—to lead the influential California Air Resources Board (CARB). Sanchez replaces Liane Randolph, who resigned after more than four years at the helm, citing exhaustion from steering the agency through a period marked by federal hostility and complex policy battles.
Sanchez is no stranger to the front lines of climate policy. She has been a close adviser to Newsom since 2021, helping negotiate international agreements and crafting state-level climate initiatives. Her appointment comes as CARB faces a crossroads: the Trump administration is actively rolling back the agency’s regulatory authority, while affordability concerns about clean energy policies are mounting at home. The agency’s low-carbon fuel standard, for example, became a flashpoint last year after staff estimated it could raise gas prices by 47 cents per gallon—a figure later walked back, but not before drawing sharp criticism from industry and the public alike.
Dan Sperling, director of the Institute for Transportation Studies at UC Davis and a former CARB board member, summed up the challenge: “The old paradigm, aggressive regulation, is no longer a tool available to them. At the same time, they’ve got to deal with the affordability narrative.” Sanchez herself acknowledged the speed and effectiveness of the Trump administration’s new tactics against electric vehicles and clean energy, noting, “They had four years to study what they did wrong in the first administration and employ new tactics.”
With only a year left before Newsom’s term concludes, Sanchez’s task will be to keep CARB steady and avoid political missteps as the agency develops new cap-and-trade rules, methane regulations, and potentially new EV incentives. Her leadership will be crucial as California fights to defend its authority and climate ambitions against what is shaping up to be a pitched battle with Washington.
The stakes could hardly be higher. As Newsom put it in his letter, “California will not stand by. We will continue to lead, because we have no choice; the lives and livelihoods of our people depend on it.” Whether the state can maintain its climate momentum amid federal pushback and economic headwinds remains to be seen, but one thing is clear: California is not giving up the fight.
