Declaring climate change to be “the greatest challenge humanity has ever faced,” former Vice President Al Gore on Monday exhorted nearly 1,000 high school students to make a generational commitment to save the planet.

“There is no challenge more important and we need your help,” Gore said.

While the speech was live, it was shown via a computer that projected the man who has made global warming a personal crusade tinged with an almost religious fervor onto a giant screen at the Warner Grand Theatre. In the audience were freshmen through seniors who attend the Port of Los Angeles High School located just a few blocks away.

Gore, tie-less and wearing an open-necked shirt with a sport jacket, was beamed from a location in downtown Los Angeles, where he was busy preparing to launch his 24-hour Climate Reality project, a live-streamed event focusing specifically on carbon pollution that begins at 11 a.m. Tuesday and runs through midday Wednesday.

During a one-way address to the students that lasted about 15 minutes, Gore implored them to take up the cause that he said could be their defining moment.

“It is your generation that is going to get hit the hardest,” he said. “The bigger downpours and floods and droughts and rising seas that we’re seeing, the stronger storms — all these things can sound a little scary. But I want you to focus on the opportunity and the hope because we can solve this.”

Speaking with his familiar Southern drawl, Gore lauded the city and port of Los Angeles for taking the lead in green initiatives over the past several years.

But more needs to be done, he said, telling the students that if the problem isn’t addressed in their generation, “another generation of students will be sitting in your seats” in 2050 wondering “why you didn’t do more to stop it.”

“If you set your minds to it,” he said, “there’s absolutely nothing you can’t do.”

Taking the theater’s stage in person before Gore appeared on screen, Rep. Janice Hahn, D-San Pedro, praised the Nobel Peace Prize winner for his “leadership and vision” on the issue.

“It really is what is going to save our planet,” Hahn said of the fight to stop global warming.

“Personally, I try to do my own part,” she said, urging the students to make environmentally sound choices in the kinds of cars they drive in the future. “I drive an all-electric vehicle, plugging it into my garage every night. When I’m in Washington, D.C., I’m driven around in a Prius Hybrid.”

“It’s clear that global warming has changed our climate and if we don’t do something now, we will have lost the moment to save the planet,” Hahn said.

Port of Los Angeles High School science teacher Rachel Bruhnke said students at the school have focused on environmental studies that include the local wetlands and sponsoring a “green festival” every year.

Gore has drawn criticism, including strictures from some scientists who question the ability to make dire long-term projections based on the available data. The issue also has lost some of its political steam with Americans focused more on the persistently moribund economy, according to public opinion polls in recent years.

The heating of the earth’s surface appears to have slowed in the past 15 years, according to recent reports. What that means, however, is a matter of dispute, with climate change scientists arguing that the findings merely reflect random changes or that the “missing” heat is temporarily settling in the ocean.

There remains a scientific consensus that global warming is the result largely of people burning fossil fuels — coal, oil and natural gas.

“Scientifically, there’s no controversy,” Bruhnke said. “But there’s so much fear in our political and economic realm. It’s not alternative thought, it’s just fear. … We need to adapt philosophically. Our technology has outpaced our philosophy and we need to grow up.”

Students were urged to use their time, financial resources and voices — along with their innate digital command of social media — to spread the message.

“Our ability to communicate across the globe in milliseconds and your generation — those are our two greatest assets,” Maggie Fox of the Climate Reality organization told the students. “Your part is to take these ideas and tools and drive them as far and as wide and as aggressively as you can.”

“Are you all inspired now?” Los Angeles science teacher John Zavalney, who helped organize the event, asked the cheering students at the end of the assembly. “Go out there and make a difference, change the world.”