DAVOS, Switzerland -- Former U.S. President Bill Clinton told corporate chieftains and political bigwigs Saturday that climate change was the world's biggest problem - followed by global inequality and the "apparently irreconcilable" religious and cultural differences behind terrorism. [...]

"First, I worry about climate change," Clinton said in an onstage conversation with the founder of the World Economic Forum. "It's the only thing that I believe has the power to fundamentally end the march of civilization as we know it, and make a lot of the other efforts that we're making irrelevant and impossible."

Clinton called for "a serious global effort to develop a clean energy future" to avoid the onset of another ice age.

He also said the current global system "works to aggravate rather than ameliorate inequality" between and within nations - including in the United States, where he lamented the "growing concentration of wealth at the top," alongside stagnation for the middle classes and rising poverty.

"I don't think we've found the way to promote economic and political integration in a manner that benefits the vast majority of the people in all societies and makes them feel that they are benefited by it," he said. "Voters usually see ... issues from the prism of their own experience."

Clinton won frequent enthusiastic applause - not a common situation at the annual gathering in the Swiss Alps - for articulating a global vision more conciliatory and inclusive than the one many of the assembled tend to associate with U.S. politics.

People around the world "basically want to know that we're on their side, that we wish them well, that we want the best for them, that we're pulling for them," he said.

Clinton called on current world leaders to seek ways of easing the "apparently irreconcilable religious and cultural differences in the world, that are manifest most stunningly in headlines about terrorist actions but really go far beyond that."

"You really can't have a global economy or a global society or a global approach to health and other things unless there is some sense of global community."

Former Australian foreign minister Gareth Evans was listening. "He's a great performer and then he's got the greatest convening power of anyone now in the world, I think, and the greatest capacity to articulate things that matter," said Evans, who now heads the International Crisis Group, a think tank.

Clinton also dispensed advice on the issues of the day.

In Iraq, he said, the United States should not "give this thing up and say it can't work," but should consider "drawing down some of our troops and reconfiguring their components, trying to increase the special forces (and) putting them in places where they're not quite as vulnerable."Iran, he argued, must not be allowed to acquire nuclear weapons, and neither economic sanctions nor "any other option" should be ruled out as ways of preventing this. But he warned there would be "an enormous political price to pay if the global community ... looked like they went to force before everything else has been exhausted."

Clinton also suggested the West should be more open to eventual dialogue with Hamas, the radical Palestinian group whose election victory stunned the world this week and clouded the prospects of any resolution to the conflict with Israel.

"One of the politically correct things in American politics ... is we just don't talk to some people that we don't like, particularly if they ever killed anybody in a way that we hate," he said. "I do think that if you've got enough self-confidence in who you are and what you believe in, you ought not to be scared to talk to anybody."

"You've got to find a way to at least open doors ... and I don't see how we can do it without more contact," he said. Hamas might "acquire a greater sense of responsibility, and as they do we have to be willing to act on that."

Klaus Schwab, the forum's founder and organizer, asked Clinton to advise the next U.S. president, noting that this person might either be married to Clinton or listening in the audience _ an apparent reference to Sen. John McCain, seated in the first row along with Microsoft's Bill Gates and other invitees.

"In this world full of culturally charged issues I think we should make it clear that Senator McCain and I are not married," Clinton joked as the audience burst into laughter.

The comment earned Clinton a slap on the back from the Arizona Republican, who fought a crowd to get to the former president after the event."Interesting talk," said the beaming possible 2008 presidential contender. "You got us both in trouble!"