Former Vice President Al Gore on Sunday told graduates of Carnegie Mellon University they could become part of the next "hero generation" in American history by solving environmental problems.
In a commencement address before a record crowd of about 10,000 people, the Nobel laureate said there had already been two "special generations" of Americans: the one that founded the country and the one that defeated fascism during World War II.
"You, I hope and expect, will be called upon to be part of the third hero generation in American history," by countering the threat of global warming, he said.
"We face a planetary emergency," Gore said. "The concentrations of global warming pollution have been rising at an unprecedented pace and have now given the planet a fever."
Carnegie Mellon had provided "great leadership in confronting what I regard as the most serious crisis our civilization has ever confronted," partly by becoming a major buyer of retail wind power, he said.
Alternative energy sources such as the sun and wind can replace fossil fuels, Gore said, but "we need one ingredient that you represent. We need political will; we need your dedication; we need your hearts."
Another speaker at the ceremony was Randy Pausch, a Carnegie Mellon professor with terminal cancer whose inspiring "last lecture" about childhood dreams made him an Internet video sensation.
Pausch said he was told in August it was unlikely he would live for more than six more months, but that he was now surviving into his ninth month.
"We don't beat the reaper by living longer, we beat the reaper by living well and living fully," he said. "I think the only advice I can give you on how to live your life well is, first off, remember ... it's not the things we do in life that we regret on our deathbed, it is the things we do not."
What matters, he said, is that he can look back and say, "pretty much any time I got a chance to do something cool, I tried to grab for it, and that's where my solace comes from."
Gore, who was awarded the Nobel Peace Prize in 2007, received an honorary doctorate in humane letters.