Gore, whose documentary "An Inconvenient Truth," won an Academy Award earlier this year, was awarded the prize earlier in the day along with the U.N.'s Intergovernmental Panel on Climate Change, an international network of scientists, for spreading awareness of man-made climate change and laying the foundations for counteracting it.
Shortly after the announcement, he pledged to donate his share of the $1.5 million prize money to the Alliance for Climate Protection, a bipartisan nonprofit organization that is devoted to changing public opinion worldwide about the urgency of solving the climate crisis.
"This is just the beginning," Gore told reporters at a meeting of the group. "Now is the time to elevate global consciousness about the challenges that we face."
Gore had been widely tipped to win Friday's prize, which expanded the Norwegian committee's interpretation of peacemaking and disarmament efforts that have traditionally been the award's foundations.
"We face a true planetary emergency," Gore said. "The climate crisis is not a political issue, it is a moral and spiritual challenge to all of humanity."
The Nobel committee chairman, Ole Danbolt Mjoes, asserted that the prize was not aimed at the Bush administration, which rejected Kyoto and was widely criticized outside the U.S. for not taking global warming seriously enough.
"We would encourage all countries, including the big countries, to challenge, all of them, to think again and to say what can they do to conquer global warming," Mjoes said. "The bigger the powers, the better that they come in front of this."
The Norwegian Nobel Committee said global warming, "may induce large-scale migration and lead to greater competition for the earth's resources. Such changes will place particularly heavy burdens on the world's most vulnerable countries. There may be increased danger of violent conflicts and wars, within and between states."
"His strong commitment, reflected in political activity, lectures, films and books, has strengthened the struggle against climate change," the Nobel citation said. "He is probably the single individual who has done most to create greater worldwide understanding of the measures that need to be adopted."
Even before Gore's Nobel prize was announced, speculation began over whether a Nobel medal might cause Gore to.
CBS News chief Washington correspondent Bob Schieffer said entering the race now would require Gore to overcome some substantial political obstacles.
"The core of his support would have to come from that part of the Democratic Party that Hillary Clinton seems to have sewed up so far," he told CBS Evening News anchor Katie Couric. "The other part of his support would have to come from kind of the idealistic wing, that would be those voters that are for Barack Obama. I simply don't see him peeling off very much support from either of those two candidates and that would make it very, very difficult for him, it seems to me, to raise the money."
Two Gore advisers, speaking on condition of anonymity because they are not authorized to share his thinking, said the award will not make it any more likely that he will seek the presidency in 2008.
If anything, the Peace Prize makes the rough-and-tumble of a presidential race less appealing to Gore, they said, because now he has a huge, international platform to fight global warming and may not want to do anything to diminish it.
One of the advisers said that while Gore is unlikely to rule out a bid in the coming days, the prospects of the former vice president entering the fray in 2008 are "extremely remote."
As he left the room after making his statement, Gore ignored reporters asking if he planned to get into the presidential race.
"Winning a Nobel Peace Prize is a life changing event," Dylan Malone, who runs a Web site called AlGore.org, which advocates a Gore presidential run, told CBSNews.com's Brian Monotopoli. "He's done the slideshow, made the movie, won every accolade that our society has to give. There's nowhere else to go to take it to the next level in my mind."
According to recent CBS News polls, Gore remains popular among Democratic primary voters. In a poll conducted this summer, 55 percent of likely Democratic primary voters said they viewed the former vice president favorably, while only 20 percent had an unfavorable view. In April, a CBS News poll found that 35 percent of Americans believe Gore's positions go too far in protecting the environment at the expense of economic concerns, while 48 percent believe he strikes the right balance. (Read more CBS News poll analysis on Gore.)
Gore supporters have been raising hundreds of thousands of dollars for petition drives and advertising in an effort to lure him into the Democratic presidential primaries. One group, Draftgore.com, ran a full-page open letter to Gore in Wednesday's New York Times, imploring him to get into the race.
"I think the inconvenient truth for Al Gore president dreamers is he doesn't really want to run and a lot of Democrats think that's a wise decision," said Jim VandeHei, executive editor of Politico.com, on CBS News' The Early Show. "Al Gore does not have that fire in the belly that you need to mount a national campaign... But more importantly, Democrats seem satisfied with the candidates that they have right now."
Gore, 59, has been coy, saying repeatedly he's not running for the Democratic presidential nomination in 2008, without ever closing that door completely.
He was the Democratic nominee in 2000 and won the general election popular vote. However, Gore lost the electoral vote to George W. Bush after a legal challenge to the Florida result that was decided by the Supreme Court.
"Eight years of the Clinton presidency - and one bitter campaign in 2000 - have left the two power couples estranged and, perhaps, resentful," writes CBSNews.com senior political editor Vaughn Ververs. "Another eight years later, Hillary Clinton is riding high in her bid to win the Democratic nomination and Al Gore is an international superstar."
Both Clintons, as well as several other presidential candidates and former president Jimmy Carter, made statements after Gore won the prize.
"Al Gore has been warning and educating us about the dangers of climate change for decades. He saw this coming before others in public life and never stopped pushing for action to save our planet, even in the face of public indifference and attacks from those determined to defend the indefensible," former president Bill Clinton said.
"Now the question is, will Al run?" added Ververs. "The answer is most likely no, but that doesn't mean Gore still can't cause plenty of trouble for Clinton in the nomination fight." (Read "The Revenge Of Al Gore?")
Peace Prize committee chairman Ole Danbolt Mjoes said a possible Gore presidential run was not his concern.
"I want this prize to have everyone ... every human being, asking what they should do," Mjoes said. "What he (Gore) decides to do from here is his personal decision."
However, when asked about the 2008 U.S. elections, he said: "I am very much in support for all who support changes."
The last American to win the prize or share it was former President Carter in 2002.
At the time, then committee chairman Gunnar Berge called the prize "a kick in the leg" to the Bush administration for its threats of war against Iraq. In response, some members of the secretive committee criticized Berge for expressing personal views in the panel's name.
Mjoes, elected to succeed Berge a few months later, referred to that dispute on Friday, saying the committee "has never given a kick in the leg to anyone."
The White House said the prize was not seen as increasing pressure on the administration or showing that President Bush's approach missed the mark.
"Of course we're happy for Vice President Gore and the IPCC for receiving this recognition," Deputy Press Secretary Tony Fratto told CBS News.
Fratto said Mr. Bush has no plans to call Gore.
The Nobel committee cited the Panel on Climate Change for two decades of scientific reports that have "created an ever-broader informed consensus about the connection between human activities and global warming."
Gore, who was an advocate of stemming climate change and global warning well before his eight years as vice president, called the award meaningful because of his co-winner, calling the U.N.'s Intergovernmental Panel on Climate Change the "world's pre-eminent scientific body devoted to improving our understanding of the climate crisis."
Members of the panel, a network of 2,000 scientists, were surprised that it was chosen to share the honor with Gore, a spokeswoman said.
"We would have been happy even if he had received it alone because it is a recognition of the importance of this issue," spokeswoman Carola Traverso Saibante said.
Climate change has moved high on the international agenda this year. The U.N. climate panel has been releasing reports, talks on a replacement for the 1997 Kyoto Protocol on climate are set to resume and on Europe's northern fringe, where the awards committee works, there is growing concern about the melting Arctic.
Eighty-four percent in the U.S. believe world temperatures are rising, according to a poll last month by The Associated Press and Stanford University's Woods Institute for the Environment. Yet while about seven in 10 said they want strong public and private action to help the environment, fewer than one in 10 said they had seen such steps in the past year.
Jan Egeland, a Norwegian peace mediator and former U.N. undersecretary for humanitarian affairs, also called climate change more than an environmental issue.
"It is a question of war and peace," said Egeland, now director of the Norwegian Institute of International Affairs in Oslo. "We're already seeing the first climate wars, in the Sahel belt of Africa." He said nomads and herders are in conflict with farmers because the changing climate has brought drought and a shortage of fertile lands.
Gore's climate change effort has had its share of criticism.
"Awarding it to Al Gore cannot be seen as anything other than a political statement. Awarding it to the IPCC is well-founded," said Bjorn Lomborg, author of "The Skeptical Environmentalist.
He criticized Gore's film as having "some very obvious mistakes, like the argument that we're going to see six meters of sea-level rise," he said.
"They (Nobel committee) have a unique platform in getting people's attention on this issue, and I regret they have used it to make a political statement."
Also, a British judge said in a ruling published Wednesday that some assertions in his documentary were not supported by scientific evidence. The case involved a challenge from a school official who did not want the film shown to students.
The ruling detailed High Court Judge Michael Burton's decision this month to allow screenings of the film in English secondary schools. The judge said that written guidance to teachers, designed to ensure Gore's views are not presented uncritically, must accompany the screenings.