The man of the hour was almost an hour late.

When University President Levin asked the attending governors at today’s climate change conference to join him for a photograph, the murmurs swept a packed Woolsey Hall. “Where is Arnold?”

As if on cue, building the suspense as only a Hollywood veteran could, California Governor Arnold Schwarzenegger emerged from a back door onto Woolsey’s stage, triggering thunderous applause as he joined Levin and three other governors for a photograph.

Connecticut Governor Jodi Rell, Kansas Governor Kathleen Sebelius and New Jersey Governor Jon Corzine had just finished delivering their remarks and signing a policy statement on federal-state partnership to curb greenhouse-gas emissions when Schwarzenegger stole the stage.

As he added his signature, frenzy seized the herd of photographers at the foot of the stage. Schwarzenegger paused deliberately, posing and smiling broadly at the press, and drawing chuckles from the audience.

Yale brought prestige, Nobel Laureate R. K. Pachauri brought expertise and Schwarzenegger brought star power to the much-hyped conference, which Yale officials have said they hoped would be an impetus for real momentum on the climate change issue, echoing President Theodore Roosevelt’s conference of governors 100 years ago at the White House, which prompted the modern environmental movement.

In his 23-minute speech, bookended by standing ovations, Schwarzenegger emphasized the urgency of the global warming threat and called for action without waiting for Washington.

“We don’t wait for Washington because Washington is asleep at the wheel,” he said to applause. “America has to lead, and we’re doing so even without Washington.”

Schwarzenegger presented an analogy between the defining feature of his entertainment career — bodybuilding — and what has become the defining theme of his political career — climate change.

Both body-builders and environmentalists were originally considered weird and outside the mainstream, he said, but just as weightlifting has become a mainstay at fitness clubs nationwide, environmentalism is finally starting to become a mainstream current of political thinking.

He said the environmental movement, too long dependent on guilting people into action, is on the verge of a new inspiration based on passion.

The political deadlock that has paralyzed progress on climate change is “about to be broken,” he predicted, and he said any of the three presidential contenders would be good for the environment. But, riffing on the popular Discovery Channel show “Mythbusters,” he said he wanted to dispel the illusion that Republicans and businesses stand in the way.

Schwarzenegger heralded the example of California, the world’s seventh-largest economy, as a new symbiosis between the market and the environment.

“Capitalism, long the alleged enemy of the environment, is today giving new life to the environmental movement,” he said in his trademark accent.

Turning to politics, he said not only were mainstream Republicans, taking himself as an example, not an obstacle, but environmentalists could sometimes even be obstructive, he said. He said the red tape created by some “environmental regulation” could actually hinder pragmatic “environmental progress.”

He predicted the advent of an environmental revolution, like the industrial and technological revolutions that came before. Young people would be instrumental in embracing and advancing that revolution, he said.

“Things are about to move our way,” he concluded.