The President gave the commencement address at the University of California-Irvine on Saturday, and during his remarks he took a shot at climate-change deniers in Congress, saying that to deny the reality of global warming is akin to insisting that the moon is made of cheese.

“When President Kennedy set us on a course for the moon, there were a number of people who made a serious case that it would be too expensive, that it would take too long,” the President said. “But nobody ignored the science. I don’t remember anyone saying the moon wasn’t there, or that it was made of cheese.”

During his 25-minute address, the President received three standing ovations and frequent applause and whistles. The more than 30,000 people attending the commencement ceremony in Angel Stadium in Anaheim were urged by the President to combat global climate change head-on, and not be stymied by “a stubborn status quo.”

Regarding those in congress who refuse to take action on environmental issues the President said, “There are some who duck the question by saying, ‘Hey, I’m not a scientist.’ Let me translate that for you: What that means is, ‘I accept that man-made 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.'”

The speech, which comes just two weeks after the release of the President’s ambitious new climate change regulations, included the announcement of a $1 billion competition in which communities that have been impacted by natural disasters can receive fund to rebuild in sustainable and resilient ways. It will encourage the adoption of plans to mitigate and adapt to the impacts of climate change.

Perhaps the most important bit of advice, though, the President offered the graduating class, was to be on guard against cynicism. “Cynicism has never won a war, or cured a disease, or started a business, or fed a young mind, or sent men into space,” the president said. “Cynicism is a choice.  Hope is a better choice.”

He pointed out that despite the negativity often associated with political discourse, it’s important to remember that in recent years, the number of states that recognize same-sex marriage has doubled, more people have health insurance, and fewer people are fighting in wars.