With US President Donald Trump skipping the UN’s climate summit in the Amazon, California Governor Gavin Newsom seized the global stage on Tuesday and launched a fierce attack on Trump’s fossil fuel agenda.

The outspoken Democrat, often mentioned as a possible contender for the 2028 presidential race, did not hold back. He accused Trump of “doubling down on stupid” by supporting Big Oil and abandoning international climate commitments.

“It’s a moral commitment, it’s an economic imperative,” Newsom said when asked about the issue during the COP30 summit in Belém, a city deep in Brazil’s Amazon region. “It is an abomination that he has twice, not once, pulled away from the accords.”

Newsom vowed that a future Democratic administration would rejoin the Paris Agreement “without hesitation.”

Trump’s Climate Record Under Fire

After returning to office in January, Trump withdrew the US from the Paris Agreement for a second time, repeating the move he first made during his earlier term. The president has long dismissed the concept of human-driven climate change, calling it a “con job.”

In contrast, Newsom highlighted California’s achievements on clean energy. Appearing alongside Pará Governor Helder Barbalho, he proudly noted that nearly two-thirds of California’s power now comes from renewable sources. Between sips of açaí juice and bites of tropical fruit, he described California as “the world’s fourth-largest economy that’s proving you can grow and go green at the same time.”

From there, Newsom’s day turned into a diplomatic sprint. He met with officials from Germany’s Baden-Württemberg, Brazil’s Minister for Indigenous Peoples, and the Brazilian president of COP30. Each appearance drew large media crowds more commonly seen around national leaders.

States Step Up as Washington Steps Back

Still, Newsom’s influence, like that of other regional leaders, has limits. Governors do not take part in official COP30 negotiations, which opened this week with renewed global calls for climate action.

New Mexico Governor Michelle Lujan Grisham, who was also in attendance, acknowledged the constraints. “Certainly our meetings with leaders at the UN and others were to demonstrate that we’re interested in any possibility that does more about that direct negotiation and representation,” she said.

Her takeaway was clear. “When the federal government leans in, we do more. And when they lean out, we do more. It’s both.”

‘A Good Thing’ Trump Stayed Away

Christiana Figueres, one of the architects of the Paris climate accord, suggested that Trump’s absence might actually help progress. “I actually think it is a good thing,” she told reporters, noting that while Washington may still coordinate quietly with oil-producing nations like Saudi Arabia, “they cannot take the floor and directly bully other nations.”

Climate Efforts Beyond Washington

Despite the federal pullback, experts say American cities and states still hold substantial influence. According to a University of Maryland study, if local governments intensify their green initiatives and a climate-friendly president takes office in 2028, US emissions could drop by more than 50 percent by 2035, coming close to the 61–66 percent reduction once targeted under President Biden.

“The president can’t throw a switch and turn everything off. That’s not how our system works,” said Nate Hultman, who led the study.

He added that even states with conservative leadership are seeing market-driven growth in renewables. Texas, for instance, led the nation in renewable energy generation last year.

Still, challenges remain. Trump’s Republican allies recently passed legislation to cut short clean energy tax credits, a move experts warn could slow investment in renewables. His administration has also blocked global initiatives such as a carbon tax on shipping, threatening retaliation against countries that supported the proposal.

‘Trump Is Temporary’

As the summit continued, Newsom urged world leaders not to be intimidated by Trump’s policies or rhetoric. “Trump is temporary,” he reminded them. “You stand up to a bully.”