At the Paris Climate Summit in 2015, Jerry Brown was treated like a head of state and a climate leader par excellence. Heads turned throughout the gargantuan press center as aides hustled the California governor to a row of makeshift studios where the world’s leading television networks waited. As the governor of what was then the world’s sixth-largest economy, Brown took a seat beneath the studio lights and told French TV about organizing the Under2 Coalition: 123 national, state, and local governments, representing more than a quarter of the global economy, that were collaborating to keep the global temperature rise under two degrees Celsius. Days later, the international community endorsed the coalition’s goal by adopting the Paris Agreement, which pledged to limit warming “well below” that mark.

This year, from September 12 to 14, Brown will host a follow-up meeting intended to keep the world moving toward that under-2°C future, notwithstanding the obstructions emanating from Washington. The California Global Climate Action Summit will draw thousands of people to San Francisco, Brown’s staff estimates. Government delegations from China, India, Germany, France, the European Union, Brazil—indeed, from virtually all of the world’s major greenhouse-gas emitters, except the United States—will be there, along with hundreds of mayors, governors, policy experts, business executives, climate activists, journalists, and ordinary citizens.

“We need catalytic events that propel states and people forward to turn the earth away from the catastrophic course we’re pursuing,” Brown told The Nation in an interview this past July. “This summit is a step, but it’s only a step.” He was seated on a couch in his office inside the State Capitol. Outside, the weather was hot (102 degrees Fahrenheit) and dry, foreshadowing the record-setting wildfires that would soon erupt 80 miles to the northwest.

“Is it enough?” Brown asked rhetorically. “No. Are we on a path to avoid catastrophe? No. But I want to do the maximum I can do.”

Although Donald Trump’s shadow will inevitably hang over the proceedings, the California summit was planned well before his election. Arms folded across his chest, an untouched cup of coffee beside him, Brown said the idea first emerged at the conclusion of the Paris summit. “Christiana Figueres asked if I’d do it, and I said yes.” Figueres, the Paris summit’s chair and the top UN climate official at the time, wanted a high-profile event in 2018 to accelerate progress on the way to a crucial third summit in Paris in 2020. An interim conference to share best practices, she thought, would help the world’s governments fulfill their obligation to publish action plans at the 2020 summit detailing the changes they’d make to meet the “well below” 2°C goal.

Figueres wanted California as the host because its record of climate accomplishments was second to none among the world’s major economies. The state was well on its way to reducing emissions to 1990 levels, and in 2015 Brown had signed a law that would go much further. Senate Bill 350 requires California to double its energy-efficiency savings by 2030, and to obtain 50 percent of its electricity from non-carbon sources.

Even so, Brown now finds himself under attack by climate activists who insist that he’s not doing enough. Seizing the opportunity of the summit and the media attention it will presumably attract, hundreds of groups have demanded that the governor ban fracking and halt new oil production in the state as part of a global push to leave most remaining fossil fuels in the ground—a necessity, science says, if humankind is to limit global warming to 2°C.

Nation contributors Bill McKibben and Naomi Klein are among the backers of the campaign, called Brown’s Last Chance, which has accused the governor of being too cozy with the oil industry. “During the past seven years, Brown has issued permits for 20,000 new [oil] wells while receiving over $9 million in political contributions from energy industry special interests,” the campaign has charged. On September 8, activists plan a protest march in San Francisco, part of a global Rise for Climate, Jobs and Justice demonstration.

“Brown has been all talk and little action on climate change, so I expect this summit will be more of the same,” says R.L. Miller, the co-founder of the group Climate Hawks Vote, who organized delegates at the 2014 California Democratic Party convention to interrupt Brown’s speech with shouts of “Ban fracking!” Brown was quick to lash back from the podium: “I challenge anybody to find any other state that’s done more than California.” In an interview for this article, Miller acknowledged that Brown had “a fair point,” but added: “Show me a state that’s done enough. California isn’t—not with 20,000 new oil wells.”

When asked to comment on this critique, Brown lurched forward, nearly leaping from his couch to denounce what he clearly viewed as the activists’ naive demagoguery. “What if I could snap my fingers and eliminate all gasoline in all California gasoline stations?” he demanded. “What would happen? Revolution? Killings? Shootings? It couldn’t happen…. There would be mass chaos. You’d never get close to [leaving oil in the ground] before the public reaction stopped it.”

These vexing dilemmas in the fight against climate catastrophe will be front and center at the California summit. Can the state—now the fifth-biggest economy on earth—rally the rest of the world to outflank US climate policy? Can effective international cooperation neutralize the efforts by Trump and a Republican Congress to pull the world’s largest economy in the opposite direction? Are acclaimed climate leaders like Jerry Brown doing enough? Should activists be attacking them less, or do even the best politicians need to be pushed? Perhaps most important, how do officials, activists, and everyone who cares confront the fundamental drivers of this crisis: Big Oil and the rest of the climate-wrecking industry, which continues to put its business model ahead of civilization’s survival?

The tragedy of today’s phase of the climate crisis is that Brown and his critics may both be right. Even the states and countries moving the fastest aren’t moving fast enough to outrun the gathering tsunami of climate disruption—at least not yet. And because the world delayed taking meaningful action for most of the past 30 years, largely because of resistance from Washington, emissions must now be cut at a pace and a scope that will likely require massive—and perhaps politically untenable—upheaval.

California is a prime example. “The Paris Agreement was amazing,” says Kevin de León, the former president pro tem of the State Senate, who is challenging Senator Dianne Feinstein in the midterm elections in November. “But because of SB 350, California is light-years ahead of the Paris Agreement.” Besides prioritizing green electricity and energy efficiency, the bill will shift the state’s transportation sector—the single biggest source of its carbon emissions—from gas to electricity, and more and more of that electricity will come from renewable sources. “As gas stations are ubiquitous now,” de León adds, “charging stations [for electric vehicles] will be ubiquitous by 2030.”

Moreover, even as the state cut emissions to 1990 levels (by 2016, four years ahead of schedule), its economy grew and created jobs faster than the US economy did as a whole. And much more lies in store. As de León explained, SB 350’s energy-efficiency upgrade will “create hundreds of thousands of jobs”—installing insulation, caulking windows, replacing inefficient appliances—“and those jobs can’t be outsourced overseas or to states that don’t believe in climate change.”

Yet even California has a long way to go. In 2015, Brown issued an executive order to cut emissions to 40 percent below 1990 levels by 2030. “We’re on our way, but that is a heavy lift,” said Ken Alex, the director of Brown’s office of planning and research.

The conflict between Brown and his critics is the latest iteration of a global tension that goes back decades. Advocates of stronger climate action start from a core scientific truth: To avoid utter disaster, heat-trapping emissions must fall by a very large amount in a relatively short time. Indeed, a new scientific study warns that even a temperature rise of 1.5°C to 2°C might unleash impacts like a catastrophic “dieback” in the Amazon. Meanwhile, government officials and others who administer the status quo counter with political and economic truths: Today’s societies are deeply dependent on fossil fuels and other climate-destroying activities, and shifting to a new paradigm invites powerful resistance from entrenched interests and mass opinion alike, especially if that shift is too rapid.

Shaping the entire conundrum—as Brown, unlike most political leaders, is willing to discuss—is the fact that today’s global economy demands endless growth in production, consumption, and profit, no matter the ecological consequences. A Jesuit student in his youth, Brown has long approached politics from a philosophical perspective. He applauded Laudato Si, Pope Francis’s 2015 encyclical, which assailed the consumerism and growth imperative of modern capitalism. But Brown clarified that it isn’t politically possible for any elected official, or even an authoritarian ruler, to challenge the religion of economic growth.

“Growth has to be transformed to be compatible with nature, or [at least] with decarbonizing,” he said. But the public wants growth and Wall Street demands it, so “if [political leaders] don’t achieve that, we don’t stay around very long.” Citing Chinese President Xi Jinping, Brown added: “Even if you’re a dictator, it’s not that easy, because you’ve got to maintain a certain level of legitimacy and popular support.”

Brown ridiculed the demand by activists to leave California’s oil in the ground as preposterously out of touch with such realities. “We’re trying to do more,” he said. “But we have a legislature; we have courts; we have a federal Congress and federal courts…. We’ve got a lot of elements in the political landscape that in a free society we have to deal with.”

Popular habits are not the least of the challenges, Brown continued, noting that Californians drive a total of 343 billion miles per year. The state has begun a shift to more electric vehicles, mass transit, and smarter development, but for the moment those 343 billion miles are overwhelmingly fueled by gasoline. And woe to any politician who threatens America’s addiction to driving. Indeed, California Republicans and the oil industry are attacking on this front in November with a ballot measure to repeal the 12-cents-a-gallon gasoline tax that Brown approved.

That said, Brown’s apocalyptic “leave it in the ground” scenario is a gross caricature of what activists have actually proposed. As McKibben has pointed out, they urge not a sudden halt to all oil production and consumption but rather a managed decline over the next decade and beyond. By contrast, activists argue, approving 20,000 new oil wells all but locks in fossil-fuel production for decades to come.

Brown counters that limiting production only in California makes no sense: Oil would simply be imported from elsewhere. “If you leave it in the ground in Bakersfield, don’t take it from Texas,” he admonished. Besides, “California is already leaving more oil in the ground. Our production has declined the last three years in a row, and it’s dropped by 56 percent since 1985. That’s a big drop.” In another jab at critics, Brown credited part of this decline to the state’s cap-and-trade system, “which I had to get Republican support to [extend through 2030] because our environmental friends are against cap-and-trade.”

Some of those “environmental friends” accuse Brown of killing a provision in SB 350 that would have yielded the gradual but substantial decline in oil production called for by the “leave it in the ground” campaign. The clause required the state’s oil consumption to decrease 50 percent by 2030, but it was dropped at the last minute after a three-hour meeting among de León, Brown, and their staffs. “Brown chickened out after a deal was done,” charges Jamie Court, the president of Consumer Watchdog.

With de León standing beside him, Brown told a press conference that they couldn’t muster the votes needed to pass SB 350 unless the oil provision was dropped: The industry’s opposition proved too powerful. And while Brown promised to fight harder in the future, he also noted that this was how power politics works. “You’re not surprised, when the State of California says, in law, we’re going to cut the sales of the most powerful industry in the world by 50 percent, that there’s some resistance,” he told reporters.

Miller of Climate Hawks Vote has a different take: “Brown is simply unwilling to say no to the oil industry.” Reinforcing that accusation, Consumer Watchdog’s Court cites a quote by Brown in 1994, when he was hosting a talk-radio show. Asked whether he’d been influenced by campaign contributions during his earlier gubernatorial terms, Brown replied: “You bet I was influenced…. You think you can collect $10 million or $20 million and not let it affect your judgment?” Citing the millions that energy companies gave to Brown and the state Democratic Party from 2009 to 2016, Court asked, “Doesn’t this money influence him, based on his own statement?”

“Thousands of Californians—individuals, unions, businesses, and others—have made contributions, large and small, to Governor Brown over the years,” replies Evan Westrup, Brown’s press secretary. “The governor’s focus is doing what’s best for California.”

Dan Jacobson, the state director of Environment California, is among those urging Brown to ban fracking and halt new oil production. But he credits the governor for challenging the oil industry as much as he has. “I don’t think there’s much that Jerry Brown is afraid of politically,” Jacobson says. “I mean, it’s not as if the other climate fights he’s engaged in—the push for 50 percent renewables, for 5 million electric vehicles, the gas-tax repeal on the ballot in November—don’t have massive political costs. It’s more: How much of a fight does he want to pick with the oil industry while still getting other things done?”

De León, an outspoken critic of Big Oil, agrees that there are only so many battles that one can fight against the industry—not because the battles aren’t necessary, but because the other side has so much wealth and power. “The oil industry threw [as much as] $25 million at SB 350,” he noted. “That buys a lot of influence.”

De León is fighting on as the co-author of Senate Bill 100, which requires the state to reach 100 percent clean electricity by 2045. “This is going to be the biggest, hottest debate in the Legislature this session,” he predicted in July. On August 28, in a historic vote, the California Assembly passed SB 100 by a vote of 43 to 32. After a concurring vote is taken in the Senate, which already approved a very similar version of the bill, SB 100 will need only governor Brown’s signature to become law.

The outcome of the SB 100 fight was a cliffhanger until the final hours, but these are the battles that must be won—over and over and over again, in cities, states, and countries across the world—if humankind is to limit global warming to “well below” 2°C. How to achieve such victories is arguably the most important question facing attendees at the California Global Climate Action Summit—and, indeed, anyone else who cares about our future on this planet. Given that Trump and the climate-wrecking industry have made it clear that they won’t stop, how do the rest of us stop them?