President Obama at UC Irvine

President Obama gives the keynote speech at the UC Irvine commencement at Angel Stadium of Anaheim on Saturday. (Genaro Molina, Los Angeles Times / June 14, 2014)

President Obama's commencement address, delivered to thousands of UC Irvine graduates Saturday, focused on the aspirations of the current generation and the need for optimism when dealing with future problems.

More than 8,000 graduates and their families jumped to their feet, loudly sharing their approval, as Obama took the stage to deliver UC Irvine's 50th commencement address at Angel Stadium of Anaheim.

The president applauded the graduates, who despite facing "dizzying change," represent the most optimistic generation in America today, he said.

"I'm here to tell you that you are right to be optimistic," he continued. "Consider this, since the time most of you graduated from high school, fewer Americans are at war, more have health insurance, more are graduating from college."

Saturday's commencement was the first of two ceremonies that will honor the 8,599 undergraduate and graduate students in the class of 2014. Each of UC Irvine's individual schools will host their own ceremonies Sunday.

As the graduates filed onto the field, university officials gave a brief history of each of the university's colleges and large departments and listed some of their accolades.

Obama's speech marks the culmination of UCI's year-long effort to get the president to Orange County.

UC Irvine students mailed more than 10,000 postcards and video invitations to the White House to request that the president speak at a university-wide graduation ceremony.

"This is an incredible milestone for UCI," School of Law graduate Erna Mamikonyan said. "To have a sitting president not only consider, but agree to speak at commencement, is a great achievement for UCI and speaks volumes for our institution."

The schools' faculty and students generally select their own commencement speakers, but UCI officials decided last year they wanted to host Obama to mark the campus' 50th anniversary.

Because President Lyndon B. Johnson attended the university's dedication in Irvine in 1964, UCI administrators believed having Obama speak would be an opportunity to pay homage to the college's roots.

"I'm here for a simple reason," Obama said. "You asked."

Obama also had some internal pressure to deliver the address from his assistant, Ferial Govashiri, who is a UCI alumna. Her brother is one of the thousands of students who will graduate this weekend.

"Until today, I did not understand why she greets me every morning by shouting 'Zot, Zot, Zot!' " he said of the Anteaters' fight song. "It's been a little weird."

Obama focused the majority of his speech on the issue of climate change. He urged graduates to become environmental stewards and encouraged the media to be aggressive in their coverage of the issue.

"Since this is a very educated group, you already know the science," he said. "The question is whether we have the will to act before it's too late, or we fail to protect the world we leave not just to my children, but to your children."

He seized the opportunity to announce the creation of a $1-billion fund that will invite communities that have experienced national disasters to compete for funds to help them rebuild and secure against similar events in the future.

Anthony Chen, 17, was impressed by the president's remarks.

"I think he made a lot of excellent points," he said. "He's obviously a prolific speaker, but what he said is true, we're going to change the world."

Chen proudly watched from the baseball stands with his father as his older brother stepped onto the field in his cap and gown.