Computer Climate Models — A Masochist’s Best Friend

A new paper out of Duke, Stanford, and the Environmental Defense Fund, promises that California will have a hard time fulfilling its carbon sequestration targets if climate keeps changing at the terrifying pace it has of late. Using computer models to prove its claims, if not its logic (since it has none), the paper had the usual effect that such glorified press releases do on your correspondent.

Leaving aside the fact that carbon sequestration is a bad idea, in response to questionable science, the idea that newspaper space is occupied by model-driven climate analyses day in and day out is, I admit, hard to take. Why, you ask? Well, I happen to have addressed that very question in my spiffy new book. And, if you’re very, very nice, or even if you just keep reading, you’ll see why.

Let’s start with a picture!

Computer models have come to replace reality in the public debate about climate. NASA’s “Columbia” supercomputer, Mountain View, California, 2006.

That’s a big boy! Must have something interesting to say about climate change! You bet he does! And now, just a tantalizing bit of Chapter 5 (Rise of the Machines) from Don’t Sell Your Coat:

So the ice caps aren’t melting. That doesn’t mean there isn’t plenty of other ammunition with which to scare otherwise sane people badly. Put yourself in the shoes of the global warming doomsayers. If you’re going to scare the pants off a whole bunch of folks, you’re going to need some powerful tools. Arguably the most powerful tool available for such a purpose is the supercomputer. That is why a single phrase appears in nearly every article and book dealing with climate change. Although the phrase is used in other disciplines to signify divergence from reality, in the case of climate science it has come to be equated with reality, or even to replace reality. Its proponents are passionate, tireless. Its detractors don’t really know where to start.

That phrase? Computer models.

The full formal name is general circulation models. Using gridded cells the size of Connecticut, these computer models are humanity’s effort to lasso, intellectually, what may be the most mentally uncontrollable being ever created: Earth’s climate system. There are many, many issues with models.

Using the most powerful supercomputers in existence, modelers strain to generate even faintly accurate climate forecasts, simply for lack of computing power. The ocean-atmosphere system is that complicated. Among the items that the models must attempt to compute: highly complex, poorly understood deep-sea currents; the effects of aerosols (fine pollution particles) on cloud formation; the effect of black carbon pollution on the melt rate of snow and ice, especially in the Arctic; solar radiation (via an effect known as solar dimming); volcanic eruptions; the effect of air masses of different pressure on either side of mountains (a process known as mountain torque); variations in wind patterns, particularly of trade winds that lead to El Niños and La Niñas; variations in albedo, which is the extent to which the Earth’s surface and atmosphere (ice sheets, clouds, oceans, forests, deserts, cities, farms, rivers, and lakes) reflect radiation back to space; and, finally, solar variation, including a controversial secondary effect of the Sun’s shifting phases on cloud formation in our atmosphere.

Every one of these variable quantities is being debated in the scientific literature. And in the blogosphere the debate is red hot, as exemplified by the tongue-in-cheek suggestion by more than one blogger that global warming skeptics be murdered in their sleep. Controversy aside, just measuring any one of the factors to be included in computer model simulations, at any given moment in time, is nearly impossible. Among the reasons: The planet is a lot bigger than the average person gives it credit for being. The ability to fly from one continent to another in less than half a day gives a false impression of scale, it turns out.

The state of Texas can help convey the size of the planet. The land area of Texas, at 261,797 square miles, constitutes 7.4 percent of the land area of the United States (which comes in at 3,537,441 square miles). Earth’s land area, though, is 57,505,734 square miles. The percent of the world’s land area occupied by Texas, then, is 0.45. And yet within this rather tiny amount of Earth’s surface area are several distinct climates. From the high mountain desert of El Paso in the west, where accumulating snowstorms are typical most winters, to the southernmost coast on South Padre Island where the warm Gulf of Mexico water acts as a powerful buffer against temperature extremes (especially those of winter), to oppressively hot and humid Houston, to Amarillo in the Panhandle with its four distinct seasons, to the state’s myriad river systems (each with its own micro-climate), Texas (as those who have labored to drive across any portion of it know) is enormous. Likewise, every other half-percent of the globe’s land mass is, too.

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As the models continue to foresee worse and worse scenarios, demanding more and more extreme measures from politicians and the public alike, including and specifically a darker and darker future for my native state, I have to say that California, outside of its political present, continues to be a healthy, vibrant land that I am fortunate to have known intimately, and to know still.

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