Balancing a grave discussion of global warming with a playful deadpan wit, Vice President Al Gore '69 gave the inaugural address of the Kennedy School's Belfer Center for Science and International Affairs on Friday afternoon in the ARCO Forum.

Speaking to a room packed with dignitaries and lotteried ticket-holders, Gore opened a weekend symposium addressing global, environmental and security issues.

Gore's speech, which made ample use of fold-out charts and graphs, was littered with numbers and arcane scientific theories.

But the Vice President's message was both clear and urgent.

"What we now know for sure that just ain't so is that the earth is so big that we can't have an impact on it," Gore said, adapting the familiar words of former New York Yankee Yogi Berra.

Gore put the earth's environmental problems into perspective when he unbuttoned his coat and stepped out from behind the podium to show a history of the world's population growth with his finger.

Gore walked across the whole stage with his hand near his waist, tracing the graph. Only when he got to the far end did he shoot his hand above his head to a point representing 5 billion, a rough estimate of the world's current population.

The Vice President emphasized that such tremendous population growth is having a substantial impact upon the earth.

Gore told audience members that they now breathe six times as many chlorine atoms as they did 30 years ago. While Gore acknowledged that such numbers are not entirely harmful, he said that the change in itself is frightening.

"If that amount of chlorine, in only a half a century, can change by a factor of six, then we have the power to change," he said.

Gore said that the chlorine concentrations, escalating carbon dioxide levels and rising global temperatures are all part of a mixture of problems that many have come to accept.

"This is beginning to have demonstrable effects," he said, noting melting ice he saw during a recent trip to Montana's Glacier National Park. "Pretty soon, people are going to be calling the park known as Glacier the park formerly known as Glacier."

Gore's message came at a time when environmental groups have been pressuring him not to back down from his strong stance on reducing worldwide pollution, while others have been criticizing him for having too extreme a viewpoint on the issue.

Before he began elaborating on environmental challenges, Gore spent five minutes buttering up the crowd with a sense of humor that some said had the scent of Gore speech-writer and former Crimson editor Andrei H. Cherny '97.

With a sarcastically stern face, Gore shifted quickly from routine recognitions of Harvard faculty members to a litany of facetious, self-effacing comments before his audience and hosts, including staff from the Institute of Politics (IOP).

"The IOP has spent a good deal of time studying the presidency, but not so much time studying the vice presidency," Gore lamented.