When it comes to climate change, America's most passionate voice is not in Washington, but California, where Gov. Jerry Brown spent decades attacking global warming.

But that perception is now under scrutiny, not from the right but environmentalists and critics on the left who call the governor a hypocrite.

"This week Gov. Brown is going to stand on the world stage and say California is leading the way on climate change and it is just not true," said Consumer Watchdog president Jamie Court. "The governor has made his own record of hypocrisy by failing to do anything to go after fossil fuel companies and the oil industry."

Consumer Watchdog is among a coalition of some 800 community and environmental groups, including Greenpeace and Friends of the Earth, who plan to protest Brown Thursday morning at the Moscone Center in San Francisco, where the governor is hosting a Global Action Climate Summit for some 4,000 scientists and activists from around the world.

The coalition, calling itself "Brown's Last Chance," said while the governor warns of a coming climate catastrophe he is overly accommodating to California's fossil fuel industry, accepting more than $9 million in campaign-related donations since becoming governor in 2011.

"Jerry Brown has permitted 20,000 new oil wells as governor," said a 30-second ad, paid for by Consumer Watchdog and Food and Water Watch. It features a child in front of an oil rig. "Gov. Brown how could you be so cruel and heartless?"

But Brown’s office takes exception to the ad, saying California under his leadership has led the U.S. in environmental stewardship and oversight.

"Clearly, the world needs to curb its use of oil and the phase out is already underway in California where the state is committed to cutting consumption in half. At the same time, oil production in California has dropped 56 percent," Brown’s spokesman, Evan Westrup, told Fox News.

Brown claims the industrial world can't afford to go cold turkey off oil. He claims the state is a leader in electric cars, wind and solar energy, and renewable energy targets – while also being the nation's sixth highest-producing oil state.

"We're not going to solve the problem of global warming without a lot of problems, without a lot of controversy, without a lot of heartache, but we can keep our eye on the ball and keep moving forward," Brown said Tuesday.

On Saturday, Brown went after President Trump, signing two bills making it virtually impossible for the administration to drill for oil in federal waters off California by banning any new infrastructure to support the projects.

"California's message to the Trump administration is simple: Not here, not now," Brown said in a statement. "We will not let the federal government...destroy our treasured coast."

Yet, according to records, Brown approved 233 permits for oil companies to drill in state waters, within three miles of the California coast. Environmental critics say the threat of a spill from these wells is no different than drilling in federal waters.

But Westrup says the state has not opened a new lease area since 1968. Multiple permits can be granted in existing leases.

"The number of annual permits issued has dropped since Gov. Brown took office and just 1,495 of the approx. 20,000 (onshore) permits granted since 2011 were issued over the past two years, which tracks with the drop in statewide production and the global price of oil," Westrup responded.

"While the governor complains about federal offshore drilling and President Trump, he controls four times as many wells in state waters than Trump controls in federal waters," Court said. "The governor has never met an oil permit he doesn't like. He isn't touching fossil fuels, he isn't touching oil, he isn't touching fracking, yet at same time California is burning up in wildfires."

Brown remains undeterred. Monday he signed an executive order committing California to be 'carbon free' by 2045, becoming the first state or political entity to pledge such a goal. To many, it seals his legacy as an environmental pioneer, and a symbol of resistance in the Age of Trump. Others, see it a public relations stunt.

"He talks a good game," RL Miller, told the California political newsletter Capital and Main. Miller, who runs the progressive non-profit Climate Hawks Vote, once told Brown "to stop being Chevron's stenographer."

Fox News asked Brown’s office how the governor could criticize Trump for encouraging fossil fuel development while approving the new oil-drilling permits, and to respond to any critics who may see it as a sign of hypocrisy. The governor did not provide a direct answer.

In reality, Brown has pushed for tougher environmental rules almost across the board and most mainstream green organizations recognize his political leadership, but are reluctant to criticize him on oil.

Other politicians who violate the ‘keep it in the ground’ standard are fair game, which is why others see their silence on Brown as a double standard.