Monterrey, Calif. (FORTUNE) - How can anyone living through today's bizarre and mutable weather not be concerned about global warming?

This winter, New York had its largest snowfall in history on a Sunday, followed by a 60-degree day Thursday. A week later, I sat in the audience at the TED conference in Monterrey hearing Al Gore enumerate fact after fact that underscored the gravity of the changes in global weather.

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The 1100 attendees -- including many of the world's leading technologists -- listened raptly as Gore presented his nonpartisan and well-researched speech outlining the scientific evidence that there is a dire and unprecedented change in earth's climate underway, seriously aggravated by human activity.

It's a speech Gore has been giving regularly. But this could be the year when a national uproar finally causes the nation's leaders to pay attention. A movie based on the speech comes out this summer. Meanwhile, Gore says that he is working with "all of the major environmental groups in the United States" on a new consortium that will enable them to band together on a "campaign of public persuasion" about global warming and its consequences.

The techies who were in attendance are on board. Says Google (Research) co-founder Sergey Brin, who has heard Gore give versions of the speech for several years: "The data coming in is just very compelling. The speech has consistently improved as the data has gotten worse. It's remarkable just if you look at the rise in global surface temperatures."

Bill Joy, longtime Sun Microsystems chief scientist turned venture capitalist, says his only complaint about the speech was that Gore left out some of the most powerful data -- about how melting arctic tundra in Siberia is allowing vast quantities of methane to escape into the atmosphere. That adds to the concentration of atmospheric CO2 and further worsens the problem.

One after another I heard people say they found the talk convincing and compelling. Says Kim Polese, CEO of open-source software company SpikeSource: "I just don't understand why it's still a debatable topic. The evidence is just overwhelming."

As I spoke to Polese, George Dyson walked up. He's a historian of science and also son of famed physicist Freeman Dyson, who has argued that global warming does no harm. But even George was wowed. "I question some of the evidence, but Gore made a convincing case," he said.

Gore's speech enumerates well-documented scientific evidence that the global climate is changing significantly -- and fast. Here are a few data points:

• Global CO2 levels are way outside what have been historical norms over several hundred thousand years.
• All ten of the hottest years on record, globally, have occurred in the last 15 years.
• Last summer, all-time heat records were set in both the U.S. West and East.
• Global ocean temperatures are far outside of historical norms.
• Even after last year's devastating Hurricane Katrina, the subsequent Hurricane Wilma was briefly the most severe hurricane ever recorded.
• Last year Japan hit an all-time record for typhoons --10. The previous record was 7.
• The largest downpour ever seen occurred last summer in India.
• Thirty-five years ago there were an average of 225 days when Alaska's tundra was frozen enough for trucks to drive. Today there are only 75.

Gore presented his data in elegant charts and graphs. The series of before-and-after photos of glaciers that have receded in recent decades -- from Latin and North America, Asia, Europe, and Africa -- was one of the most vivid and shocking moments in his talk.

Then there is what's happening in Antarctica and Greenland -- land masses topped with huge melting ice sheets. If these start falling in quantity into the sea -- and Gore's data suggests it's quite possible -- global ocean levels will rise appreciably. Vast coastal areas could be inundated -- areas where 20 million live around Beijing, 60 million around Calcutta, and even large portions of Manhattan.

Gore claims that none of the peer-reviewed scientific articles published in recent decades have disputed that the earth's temperature is rising, even as more than half of all articles in the US press over the same period have. We journalists, in the search for "balance," may have contributed to a national complacency.

The movie based on Gore's presentation, called The Inconvenient Truth, will be released in late May by Paramount Classics. I sat across the table briefly from Gore at a dinner after his talk, and he was effusing about what a great job the filmmakers have done.

The movie is more than just a record of the speech. "It's Al Gore's personal journey and how he got to this conclusion," producer Lawrence Bender says.

Some will object to this movie for obvious political reasons, but it is likely to catalyze a national debate we desperately need. And the world needs to be awakened if his facts are right. Bender says religious and political leaders who have seen the film -- including many supporters of the Bush administration -- have been highly supportive.

My biggest complaint about Gore's talk is that despite the overwhelming evidence he marshals of dire climate change, his upbeat promise at the end that it's not too late to do something about it is unconvincing. But there's no question we have to face reality -- we're hurting ourselves by hurting the climate. Thank you, Al Gore, for saying it bluntly.