Every day seems to be green day for California Gov. Arnold Schwarzenegger as his term terminates and he works to cement his environmental legacy.

On Wednesday, the governator started his morning in the Mojave Desert at the official groundbreaking for BrightSource Energy’s Ivanpah 370-megawatt solar power plant, the first large-scale solar thermal farm to be built in the United States in two decades.

By the afternoon, Schwarzenegger had materialized in Silicon Valley. He joined Avatar director James Cameron for a live webcast from tech company Applied Materials to unveil a new online commercial opposing Proposition 23, the ballot measure that would suspend California’s landmark global warming law. The governor considers the climate change law, known as AB 32, to be one of his crowning achievements in office. Watch the commercial:

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Backed by two Texas oil companies, Prop 23 would effectively kill the global warming law — which requires California to slash greenhouse gas emissions to 1990 levels by 2020 — by suspending it until the state unemployment rate falls to 5.5 percent for four consecutive quarters. (Something as likely to happen anytime soon as Schwarzenegger giving up his trademark cigars.)

“The people who tried to take out AB 32 through Proposition 23 are the people who are really the biggest polluters of our state, Texan oil companies,” said Schwarzenegger, sharing the stage with Cameron, who directed him in the Terminator movies and True Lies, and Tom Steyer, the founder of a $20 billion San Francisco hedge fund and the chair of the No on 23 campaign.

(Before the webcast began, an open microphone caught Schwarzenegger chatting with Cameron and Steyer. Alas, no racy reminiscences of the Terminator’s Hollywood days — just the governor enthusing over the BrightSource Energy project.)

The ad opens with a wide shot of Cameron sitting in an office surrounded by movie mementos.

“I’ve made movies about a cyborg assassin sent to annihilate humanity, an unsinkable ship on a collision course with an iceberg, and about a mineral-rich alien moon facing environmental destruction,” says the director, who has donated $1 million to the No on 23 campaign. “Those are movies. But we face a real threat right now in California. Two oil companies from Texas are pushing Prop 23. This deceptive ballot measure would be the ultimate real-life disaster, terminating our air pollution standards, sinking our clean energy economy and exploiting our environment for profit.”

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“We can do something as people who care about the future of California,” Cameron continues. “We can say no on Prop 23, to stop the dirty energy proposition. Tell your friends and family, cyborgs, and avatars, to vote no on 23 before it’s too late. “

The camera pans to Schwarzenegger, holding up a robotic arm, saying, “Why do you keeping calling me a cyborg?”

With less than a week to go until Election Day, the “no” forces appear to be on a roll, holding a three-to-one advantage over the “yes” campaign in fundraising and with polls showing Prop 23 losing by a wide margin.

But with a Los Angeles Times/USC poll this week showing 15 percent of likely voters undecided, the Terminator apparently is determined not to stop. Ever.