Dec. 18, 2007 -- On YouTube's all-time list of most-watched news videos -- just behind the sex and flash of Britney Spears -- is the newest online sensation: a decidedly unfunny, perhaps unsexy science teacher from Central High School in Independence, Ore., who wanted to reach a lot of people. So he created a YouTube video called "Most Terrifying Video You'll Ever See."
So what's so terrifying about a nine-minute video showing Greg Craven with a pen and white board? Craven makes a compelling case that humans need to fight global warming or be prepared to face disastrous consequences.
"We only get to play this game once, so ask yourself -- 'How lucky do you feel?'" Craven says in the video.
He says we shouldn't be arguing whether global warming is happening, but whether we should take action.
"Turns out, all science is uncertain, so we need to make some risk-management decisions instead and look at which is the greater risk," Craven reasons.
Drawing a simple grid, he argues that the "cost" of taking no action if global climate change is real is much greater than the benefit of taking no action if it isn't.
Six months later, the message is out in a major way. The video has attracted more than 4 million viewers and counting.
"I had the population of the United States in mind," Craven says. "That was my pipe dream."
Jeff Jarvis, a professor at the City University of New York Graduate School of Journalism, says, "This guy sent his message to his students. They sent it to more people. They sent it to more people. If he had nothing worth saying, it wouldn't have spread. There is somewhat of a meritocracy here."
It doesn't mean everyone liked what they saw. The video has more than 7,000 comments on YouTube, including unflattering ones like "My toddler drools more cogent arguments."
But regardless of how much they like it, people keep clicking and watching, which has made this science teacher a suddenly visible player in the discussion on global warming.
"He now has his own platform, his own network," Jarvis points out. "When he puts something up now, he can be assured it will get more attention because his first video did."
He has made more than 44 other videos, spruced up with some special effects. He calls them his gift to the world.
"I can't change the world. But maybe enough people working together can," he says.
Four million people might not be enough yet, but it is quite a start.