Cannes (France) (AFP) - Arnold Schwarzenegger laid into US President Donald Trump Sunday, saying his plans to revive coal would bring the world back to the horse and cart.
"He's back in the Stone Age," the Hollywood star told AFP.
The former California governor said he despairs of what Trump's energy policy, which is heavy on fossil fuels, will do to the planet.
"As far as the environment is concerned, he is misinformed," he said.
But "one man" cannot destroy the Earth, he argued, particularly a leader as ineffective as the billionaire businessman.
"So far nothing has got done since he became president. Nothing," he added.
"When I hear he wants to bring coal back, that's going backwards. The next thing he'll want to bring horses and buggies (carts) back," the actor and activist told reporters at the Cannes film festival.
"Trump or no Trump we all have to move forward," he added.
"Only people power and embracing technology to replace fossil fuels will change this," insisted the actor, whose R20 network works with local and regional leaders across the world to combat climate change.
"All great movements -- civil rights, the vote for women, the anti-apartheid movement, the freedom movement in India -- all started on a grassroots level.
"We cannot wait for London, Moscow, Beijing, Washington, Berlin, Delhi... Let's do it locally," he told AFP.
"The people have to rise up and say we got to protect what we have so we don't have climate change and seven million people dying every year because of pollution."
Schwarzenegger produces and narrates a new documentary by the son of undersea explorer Jacques Cousteau, "Wonders of the Sea 3D", which he claimed would make "people fall in love with the ocean".
- Environmental shaming -
He said the movie's positive message worked much better than "the shaming, guilt and finger pointing" that Schwarzenegger believes puts people off environmentalism.
"You can't just tell people all the time that they shouldn't fly, or drive a big car or have a jacuzzi," he told the Hollywood Reporter.
"If you want people to change you got to make people feel good about it. When you see this film you will inevitably fall in love with the ocean," he added.
Even though both Trump and Schwarzenegger are Republicans, the star has had prickly relations both politically and personally with the president.
In January, Trump blamed the low ratings of "The Apprentice" television show on Schwarzenegger, who took over from Trump as presenter.
Schwarzenegger said in March that he was quitting the show because it had too much "baggage".
He said Trump's name in the credits as executive producer scared away sponsors and viewers.
While in Cannes, Schwarzenegger, 69, also congratulated French voters on electing centrist Emmanuel Macron as president earlier this month.
Trump had praised his opponent, far-right leader Marine Le Pen.
"I love being in France," he told Screen International, adding that French people had done "a great job with the election of the president".
The "Terminator" star is also playing the world's greatest hitman in a forthcoming film being sold at Cannes, "Why We're Killing Gunther" by "Saturday Night Live" performer Taran Killam.
Schwarzenegger also confirmed he would be making a sequel to "Twins" with Danny DeVito and Eddie Murphy, called "Triplets" and that he would be returning to the "Terminator" franchise.