Rutgers University Commencement 2015

Bill Nye before he received an honorary degree during the Rutgers University Commencement at High Point Solutions Stadium in Piscataway. 5/17/15 (Ed Murray | NJ Advance Media for NJ.com)

(Ed Murray)

PISCATAWAY — Graduation day at Rutgers University is a chance for students to relax after four years of college and celebrate with family and friends before entering the real world.

Or, when Bill Nye is the keynote speaker, it's a reminder that the amount of carbon dioxide in the Earth's atmosphere is rising and its future may be a "no-way-out overheated globe."

Nye, the bow-tied host of "Bill Nye The Science Guy," used his speech at Rutgers' commencement Sunday as a platform to tell students they must find a way to stop climate change.

Though it wasn't the message some graduates were expecting, several said they were happy to get another lesson from the scientist they grew up watching.

"It's a heavy topic, but it's something that was necessary to address," said Jesse Bagley, who graduated with a bachelor's degree in science and biomedical engineering. "He's right. We all have an opportunity to make a choice as far as that goes, so it was something that we needed to hear."

Nye urged students to challenge those who dismiss climate change. The scientific consensus on climate change is as strong as the consensus that smoking causes cancer, he said.

"Climate change is a real deal," he said. "So, hey deniers — cut it out, and let's get to work."

Students chanted "Bill, Bill, Bill, Bill Bill!" before Nye's speech, a nod to his show's theme song, and said his speech was "awesome" afterward.

It's to be expected that any graduation speaker will plug their own politics, said Michael Bruchert, who earned a degree in journalism and media studies.

"I learned from Bill Nye probably more than any other science class because he is so awesome, and I was was so excited to see him speak today," Bruchert said.

That excitement was lacking among some students last year when Rutgers named former U.S. Secretary of State Condoleezza Rice its graduation speaker.

Students and faculty briefly staged a sit-in outside the university president's office and objected to giving Rice an honorary degree, citing her involvement in the Iraq War, the use of waterboarding on prisoners and other Bush administration policies.

Rice backed out and was replaced by former New Jersey Gov. Tom Kean.

Nye's selection came after a small group of students started a twitter campaign, though the university did not say whether that had any influence on its selection. Rutgers paid him a $35,000 speaker fee, according to the university.

Along with talking about climate change, Nye encouraged students to vote and briefly mentioned racial conflict, saying skin color is a consequence of ultraviolet light, latitude and climate.

"There really is no such thing as race," Nye said. "We all came from Africa. We are all of the same stardust. We are all going to live and die on the same planet, a Pale Blue Dot in the vastness of space. We have to work together."

He also offered some lighter advice.

"If you smell fresh paint, don't walk under the ladder, somebody is up there with a wet paint brush," he said. "Wear good shoes in a thumbtack factory and don't try to smoke in the rain. In fact, don't smoke at all, ever."

Adam Clark may be reached at adam_clark@njadvancemedia.com. Follow him on twitter at @realAdamClark. Find NJ.com on Facebook.