ANAHEIM, Calif. — President Obama said denying climate change is like arguing the moon is made of cheese, as he issued a call to action on global warming to Saturday’s graduates of the University of California, Irvine.

Obama told the tens of thousands gathered at Angel Stadium that Congress “is full of folks who stubbornly and automatically reject the scientific evidence” and say climate change is a hoax or fad.

“Many others duck the question by saying, ‘Hey, I’m not a scientist,”‘ Obama said in remarks prepared for delivery. “Let me translate: what that means is, ‘I accept that manmade climate change is real, but if I admit it, I’ll be run out of town by a radical fringe that thinks climate science is a liberal plot.”‘

Obama’s address to about 8,000 graduates from the Orange County campus comes two weeks after he announced a contentious plan to dramatically cut pollution from power plants. Obama also used the address to announce a $1 billion competitive fund for communities who have experienced natural disasters to rebuild and prepare for the impact of extreme weather.

He described a political system consumed by “small things” but said Americans should be determined to do “big things” like addressing climate change.

“I’ve got to admit, though, it’s pretty rare that you’ll encounter someone who says the problem you’re trying to solve doesn’t even exist,” he said. “When President Kennedy set us on a course for the moon, I’m sure some made a serious case that it wouldn’t be worth it. But I don’t remember anyone ignoring science. I don’t remember anyone saying the moon wasn’t real, or that it was made of cheese.”