Behold, this bizarre demographic. Behold this odd and simmering and rather shockingly large hunk of the American population because chances are very good that at least some of them live right next door to you and breathe the same air and steal your parking spaces and often don't shower for six days at a stretch.

And maybe, just maybe you should be painfully, dreadfully aware of them because they are -- in their quiet, seemingly innocuous way -- far more deadly than any gay evangelical preacher or meth-lab gang-bangers and far more frightening than chicken-flavored soap bubbles for dogs and far more disconcerting than Britney Spears' barren skull.

They are, in short, the deeply uninformed. The inexplicably ignorant. The wondrously numb, the disconnected, the way, way out of touch. And they are, apparently, legion.

Let me be clear. I am not speaking merely about the ideologically lopsided and the intellectually misshapen. I am not speaking of, say, those armies of happy blank-eyed red-state 'Merkins who only read NASCAR-themed Harlequin romance novels and only drink Hooters-branded energy drinks (real products, both) and who like to bury their gay sex fantasies under mountains of happy homophobic sing-along God-fearin' megachurch denial.

Nor am I speaking of your average Bush-lovin' bobbleheads who appear to get their worldly information by way of licking the stuff found on the bottom of the rocks in front of Fox News HQ and then tripping for three days while watching "The O'Reilly Factor" from the bathtub. Everyone knows about them. And no one really takes them seriously anymore.

No, I am speaking of a group far more mysterious and far more bewildering. And they number, in fact, in the tens of millions, or fully 13 percent of the American population, if this recent, 46-nation poll is to be believed. Here is one way you shall know them: They have never heard of global warming.

You read that right. According to this ACNielsen poll, there are, right now, upwards of 40 million bipedal adult Internet-using Americans living in this nation who have never, not even once, seen a program about the most dire issue facing the planet today. They have not read about it in a newspaper or seen photos in a magazine or heard about it via an award-winning documentary or seen monkey-like Republican presidents deny its existence and spit on science and mock the simply insurmountable pile of evidence in the name of oil profits and flagrant cronyism.

Who are these people, you ask? Are they, say, millions of forgotten, heavily medicated shut-ins across the land? Are they the disregarded elderly? People living in the backwoods of Louisiana or Appalachia and therefore we can't expect them to actually read or watch television or care much about the health of the planet (except, of course, to take part in a broad, 46-nation Internet survey) because they're simply too busy hunting squirrels and making fire and picking their teeth with dinosaur bones?

Or perhaps they are the very young and the desperately teenage, so packed to the skullcap with screaming hormones they can barely navigate the lousy American education system much less name the current president or flirt well on MySpace or understand how many tons of greenhouse gases are pumped into the sky to crank out one PlayStation 3. You think? Does this explain it?

Verily, it does not. Not by a long shot. Not when, for example, fully 95 percent of Latin America has heard of global warming, and 75 percent think it's a "very serious" issue. Not when the United States ranks dead last among all 46 nations in its concern for the issue of dire climate change.

No, there is something more sinister at play here. Something darker and just a little disquieting. Do you know what it is? I don't, either. Do you ask, as I do, How the hell can this be? What sort of people are these? How can this survey be accurate? How can anyone even moderately attuned to the culture not have heard of global warming, even once? Is it not part of the popular lexicon? Is it not being used to sell sexy white jeans, fer chrissakes? What, pray tell, gives?

Here is what we do know: The United States is, by far, the world's worst contributor to the root causes of global warming, and yet we are the least concerned about it. Read that again: Despite how the United States pumps more pollutants and greenhouse gases into the atmosphere than China or India or Russia, a scant 42 percent of us see the problem as "very serious." Even China and India, those irresponsible mega-polluters of the developing world we like to scoff at for their flagrant industrial waste, are far more concerned and more universally informed.

It's enough to make you look at George W. Bush and want to slap him across the face with the razor-sharp paw of a dead polar bear. It's enough to make your heart shudder as you wonder who the hell we are, really, as an ostensibly proud people, as a supposedly "unified" nation, a global leader, a role model to the planet. Is the great United States really just some sort of moral joke? Are we really leading the world in anything except warmongering and defense spending and sexual hysteria and cool iPod accessories?

Sure, the overall lack of concern is understandable. After all, the vicious GOP spin machine has been working like a rabid dog for the last six years to demonize science and mock environmentalists and sneer at the Kyoto protocol and force eminent scientists to bury their dire findings lest Dick Cheney visit them in the night with a box of rat poison and a shotgun sneer.

And then there's this: Only 13 percent of congressional Republicans see global warming as a human-caused issue, compared to 95 percent of Dems. That's right, despite the National Academy of Sciences, despite the AAAS and the Intergovernmental Panel on Climate Change, despite the U.N., despite every reputable (and often, very conservative) scientific body on the planet, half of our own Congress snickeringly denies humans have had anything to do with global warming. Ah, how proud they must be.

But while that level of willful, greedy ignorance is relatively easy to explain, this weird hunk of gaping blindness, this intellectual black hole, isn't quite so easy to figure out.

Except for this: Maybe it's the end result of the great, chronic dumbing down of the American mind. Possible?

Maybe our 13 percent blindness rate is simply the brutal upshot, the logical conclusion of all the endless stripping of school textbooks of fact and perspective, of the push for silly literalist Christian dogma at the expense of true awareness, of the systemic neoconservative drive to get Americans to stop asking questions and stop thinking for themselves and to hate and mistrust the media (except, of course, Fox News), and wouldn't you be better off just enjoying your Wal-Mart candy corn and your "Everybody Loves Raymond" DVDs and just turn off your brain because it's all just far too complicated and messy and suspicious anyway, so really, why care at all?

And oh, those dark storm clouds? Pay no attention to those. Those are just God's happy lint balls. Go back to sleep.

Mark Morford's latest book is 'The Daring Spectacle: Adventures in Deviant Journalism'. Join Mark on Facebook and Twitter, or email him. His website is markmorford.com. For his yoga classes, workshops and retreats, click markmorfordyoga.com.

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