Friday, April 06, 2007

Please, please read this

It's a Cato Institute article published in the San Diego Union-Tribune on March 11th. The author is Patrick Michaels, senior fellow in environmental studies at the Cato Institute, and a research professor of environmental sciences at the University of Virginia. He has some fascinating things to say about the International Panel on Climate Change study.

For instance, do you want a metaphor for what the Panel has come up with in terms of news about global warming?
Despite breathless news reports, there's very little in it that's new to anyone involved in global warming science. Instead, there have been dozens of stories about how scientists now believe there is a definite human influence on mean global surface temperature, and that, in recent decades, much of the warming can be attributed to the effect of increasing amounts of carbon dioxide and methane in the atmosphere.

Scientifically, this is tantamount to concluding that because Las Vegas is awash in poker chips and prophylactics, we now have high confidence that much of the recent decades' increase in economic growth has something to do with the prevalence of gambling and hanky-panky.

You probably want more meat than that gives you, so here are some highlights of Michaels' analysis of the IPCC report (emphasis mine):
The biggest story in the summary was largely missed by the environmental media. The IPCC now projects, in its mid-range scenario for carbon dioxide emissions, that the maximum rise in global sea level in this century will be around 17 inches. That's a reduction of 30 percent from what was in the Third Scientific Assessment, published just six years ago.

That's huge news, or it should be. But instead of listening to what the IPCC is saying, people are opting for the science fiction of Al Gore's "An Inconvenient Truth," whose central disaster scenario is that Greenland sheds the majority of its ice this century, raising sea level as much as 20 feet. Much of Florida disappears, and the Mall in Washington goes under water. The U.N.'s sea-level projections "include a contribution due to increased ice flow from Greenland and Antarctica, but these flow rates could increase or decrease in the future."

That's excellent hedging by the IPCC, because the authors of the summary surely knew that a paper was about to appear in the journal Science showing that an increase in the loss of ice from Greenland's big glaciers in 2004 had stopped and reversed by 2006. And was the loss of ice ever as gargantuan as Gore's imagery? Hardly. Satellite data, also published in Science last October, show that Greenland was losing a total of only 25 cubic miles of ice per year. That's teeny. There are 630,000 cubic miles of ice up there. Dividing 25 into 630,000 and multiplying by 100 gives the rate of loss: 0.4 percent of Greenland's ice per century.

I have to stop here and point out one of my pet peeves about any kind of publication that uses numbers to support a conclusion: the authors are often, shall we say, relaxed about presenting those numbers. I will not even spare Professor Michaels.

His article says "Dividing 25 into 630,000". What he meant was "Dividing 25 by 630,000".

Dividing 25 into 630,000 gives us useful information: 25,200 years (252 centuries) for all the ice in Greenland to melt assuming current melting rates. Dividing 25 by 630,000 gives us useful information, too: the percentage of the Greenland ice pack that disappears each year. If we multiply that number by 100 we get the percentage of the Greenland ice pack that disappears each century: 0.4%. That's the number Prof. Michaels derived, though the global warming student would have gone down the wrong computational path following his instructions.

Thank you for listening to that plea for correct math representation in the media. Now, back to Prof. Michaels. He mentions the level of carbon dioxide at the beginning of the 1900's:
Right now, we're only about 1.3 times that value, and there's a reasonable debate about whether we will ever get to twice that figure, because in the time frame required, technology is likely to change dramatically, in ways we can't imagine today.

For an interesting thought experiment, consider the energy and technology world of 1900, and a vision of the future. "Scientists will discover a new element called plutonium," some placard-carrying crackpot on the horse-infested streets of New York might say, "and if we compress a few pounds of it, almost all the buildings on Manhattan will be destroyed, along with their inhabitants." What a wacko! And that's nothing, compared with his assertion that, by 1975, people would fly from New York to London in a little over three hours, 65,000 feet in the air, or that all of the information in all the libraries of the Earth could be on everyone's desktop by 2000.

But that's how technology changes in a century. There were similar changes between 1800 (horse power and hand-carried letters) and 1900 (iron-horse power and the telegraph, etc.), so it's a real stretch to say we will go all the way to four times the 1900 concentration of carbon dioxide and then stay there for over a millennium. Does anyone seriously believe we will be a fossil fuel-powered society, industrially respiring massive amounts of carbon dioxide, in the year 2500?

Very much worth your time.

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