Last time I looked, it seemed to me that we are about 18,000 years into a 20,000 year or so cycle of ice cap retreat. The process is very much cyclical. The earth has been here before (without us H. sapiens), and will often again (likely without us), but the graph makes it look like the excursions are amplifying.

http://www.museum.state.il.us/exhibits/ice_ages/images/spec_map_graph.gif

(Link doesn't work; copy and paste.)(To make the graph reflect global warming, it must be inverted and reversed, which is well beyond my electronic capacity.)

The idea that humans are "causing" climate change strikes me as about so homocentric as the proposition that humans were present at the creation of the universe, and will still be present, eating peeled grapes (grown where and by whom?) on golden couches (mined where and by whom?), when the universe is destroyed.

(If the "intelligent" creator of the whole universe would rather spend an exclusive eternity with rich stupid old white guys with three chins, and those who take them seriously, than with the blue whale, the T. rex, or the hummingbird that can fly the Gulf nonstop, not to mention the humanly unimaginable assortment of creatures on the planets circling the 60 septillion (18 zeroes) stars that the astronomers currently estimate, doesn't that make the creator pretty stupid?)

Paleoclimatology, digging its bores into the ice caps and the rings of the bristlecones on the way to the summit of Mt. Evans in the Rockies that predate the pyramids, is well on the way to explaining much of human history that was previously considered magical or divine (if there's a difference), such as the disappearance of the Anasazi, the sexual prowess of the Jade Concubine, and the baffling question of why anyone would ever have wanted to live in Israel. (It may once have made sense, long ago.)

If Nick Brooks is right, it may even explain why H. sapiens invented "civilization," by which I take it he means the agricultural methods that eventually led us to the cheap, abundant food that has us eating and breeding ourselves into pending extinction.

(Note that, at Brooks's onset of civilization, we were well past the current retreat of the ice caps past the mean for the last three-quarters of a million years.)

Brooks's suggestion that civilization led to a "harder life," of course, is just stupid, and ignores the numbers. I remember reading somewhere (and I'm too lazy to go find it tonight) that at their peak the Neanderthals numbered maybe 10,000 living souls on the earth, and our Cro-Magnon ancestors back then couldn't have been much more numerous. (DNA studies will eventually reveal whether we screwed them to death or just killed them.) We were only about 250,000 at the time of Jesus.

If Brooks thinks civilized life is hard, let him spend an Arctic winter living in snow caves and eating dead grass and the insects and rodents he can catch with his bare hands, since I doubt he could knapp a flint. Hard, my ass.

The invention of agriculture led us to a billion H. sapiens on the planet in the year 1804. Compare that to 10K Neanderthals. Science and technology brought us to something like 2.5 billion H. sapiens when I was born, something like 7 billion now, maybe another doubling if I live long enough. Harder life, my ass. Count your living children.

The Chinese started killing their children back before the Yellow and the Yangtze reached the sea. Back then, the Colorado probably did, too.

Now, we're next.

There is no doubt that adding six billion humans over the course of the last couple of centuries, an increasing percentage of whom are merrily vaporizing increasing amounts of per-capita carbon into the atmosphere, has done a dandy job of accelerating the retreat of the ice caps. The point is that the current retreat, one among many, started back when the glaciers were in southern France and south of Kansas City, and our ancestors were blowing paint against their hands in the caves of Lascaux.

The Illinois graph (and now I can't get the link to work) makes it look like we were already headed toward the greatest retreat of ice on the poles in the last three-quarters of a million years, although probably still more than when the ichtyosaurs were swimming in western Kansas. The only question is whether human acceleration will further decrease the ice caps and increase the water level, or just get us there sooner.

There is also no doubt that Western Civ of the 21st Century is the softest time and place in the history of the planet to be a H. sapiens. The measure is in our waistlines and our head-count. Doesn't mean that living in "civilization" is a good thing. Ruth and I fled the concrete beehives for the hills of the Ozarks a quarter-century ago.

The scientific and technological revolution that made the head-count possible is younger than some of our oak trees. My current best guess is that it is an evolutionary dead end, and that H. sapiens are genetically predisposed to conquer adversity but not to suffer success. Perhaps the acceleration of climate change will turn out to be a humane thing, if it means there are fewer of us surplus humans when the water runs out.

The mainstream media and the blogosphere are full of claims that humans are "causing" climate change. We make Ozymandias look like a shrinking violet.