Friday, April 11, 2008

Dishonest Dissent (and Climate Change for Dummies)

Last December, a group of academics wrote an open letter to the United Nations, disputing the official findings of the International Panel for Climate Change. I nervously scanned it for alumni, and was disappointed to find one Howard C. Hayden, professor emeritus of physics from the University of Connecticut. Here he is again, a credentialed speaker classing up a legion of blowhards, think-tankers and non-scientists at the Heartland Institute. (Both of these were pointed out here). I should have at least heard his name before: he was winding up his professorial career at just about the same time I was underachieving my way through grad school at UConn, ten years or so ago. He worked in the field of atomic physics, and I assume that the lab in the basement with all the potential energy envelope functions taped to the wall was his. The physics building was adjacent to the one I worked in, and I walked by those posters almost every day.

Evidently, his contrarian hobby preceded his retirement. For some of the time he was professionally active, he ran a journal for a while dedicated to a dissent of general relativity. In and of itself, I wouldn't call this a bad thing. Stubbornness is a necessary part of any good researcher's constitution, and even the most cherished theories, especially the ones which are hard to verify experimentally, should be challenged regularly. Even if they don't result in a refutation of accepted belief, these exercises can still open up conceptual space (you'll need a good challenge to get through to people), and they can shore up any weak areas in the theory. One can defy convention and still be honest, and this is one reason that I find, say, Roger Penrose's unusual ideas about the intersection of AI and quantum mechanics to be worthy. On the other hand, one of the most annoying cultural developments in modern America has been to confuse contrarianism with truth, that is, to adopt all of the smug counterintuition without the inconvenience of actually having to be right about stuff (a tone which my inner Yankee correctly identifies as the oleaginous voice of Marketing). Any scientific opinion is ultimately judged on its utility. It really does have to match the available observations.

I made a point to watch An Inconvenient Truth before I read Howard Hayden's pamphlet, A Primer on CO2 and Climate. I don't fault Al Gore for bringing the message to the public, but I do think he made some errors of judgement in the presentation: his graphs had illegible axes for the most part, and he relied too much on projections (isn't ten feet enough?), single plot points ("today's" CO2), dramatic anecdotal evidence (Katrina and mosquito-borne disease), and false optimism. I furthermore found the whole Albert Agonistes business too goddamn self-indulgent by a mile, but I think he's on the right side of the debate, even if he's doing marketing too.

What separates Gore from Penrose from Hayden? One is where they fit in the hierarchy of political power. Hayden fashions himself a dissenter, but he's really arguing from a position of convenience, saying that nothing could possibly go wrong with our current consumption patterns. I think Al Gore also gets some thrill from defying convention as well, but the people who find his views useful aren't nearly so obvious or powerful (yes, he's stoking an electoral base, and yes, scientists are always greedy for funding, but to my knowledge, there is no Big Climate Science lobby pulling his strings), and conservation as a basic philosophical principal is certainly more defensible than a position that says we can return carbon to the atmosphere indefinitely, and without consequences. There are differences of style and credibility too. Unlike the charming Penrose, Hayden makes a habit of belittling his critics, and, also unlike the mathematician, he has published zero scientific research in the field in he most likes to moan about. For a guy who gets so much mileage dismissing Al Gore's non-scientific background (and others', inaccurately), Howard C. Hayden keeps some strange company on the lecture circuit, and while the position of scientists may tend toward some nuance vis a vis the IPCC's position, Hayden's presents a pile of skepticism that is more reactionary than it is rational. Hayden is a capable guy who's right about some things, who has been an interesting voice at times, but who is, by the available evidence, a professional dickhead.

His Primer is one of several micro-press publication he's put out on a similar theme. He also writes a monthly newsletter on energy, and milks organizations like Heartland for dodgy gravitas and speaking fees. It's about fifty pages long, fluffed with lots of figures, and it's not overly technical. The book is fashioned more as a refutation than as a coherent proposition, but I'm okay with the format. He opens it up with several reasonable-sounding questions (Is the earth warming? Is mankind responsible? Is it bad? Can we change it?) which are fair to ask, but they are light on the culpability. There's no question that we people have dug out and liberated some hundred or more gigatons of carbon into the atmosphere, carbon that had been sitting out of the climate game for a few hundred million years before the industrial revolution rolled around. I prefer to ask: What consequences are reasonable to expect from doing that?

The early pages of his pamphlet focus on the famous CO2 data from the Mauna Loa observatory, shown here. He plots these data on an axis that starts from zero, trying to emphasize that this increase is negligible and warning the reader of the lies that statistics are capable of. But crying a lie is itself misleading: even counting for the viewpoint of the graph, we're still seeing a 15% increase in atmospheric CO2 concentration at the observatory.


To decide whether that is a significant increase as far as global climate is concerned, we have to consider how the absorption of energy by CO2 affects the heat balance of the earth. All objects emit energy as a function of their temperature, and hotter objects emit higher energy (shorter wavelength) radiation and more of it. The emission spectrum of the earth has a peak in the infrared region of the electromagnetic spectrum, but it varies from that of a black body (that is, an ideal emitter) in several ways. Where the atmosphere is transparent to infrared, the emission is dominated by the earth's surface, which is hotter than the atmosphere. Most infrared is absorbed by atmospheric gases, however, (mostly by water vapor) and is re-emitted above the earth (all matter will emit energy as a function of temperature), but not all of it goes into space, some goes back down. The effect is reduce the rate of heat rejection to space. The system gets a little bit hotter and therefore more emissive until it gets to the point where it eliminates energy as fast as it takes it in.** A good analogy is a radiation shield (the heat shield under your muffler is one), which, unlike one dumb point by Howard Hayden, is in my fundamental (okay, introductory) heat transfer text. Still, if you're not careful with your vocabulary, you can get into traps that cranky deniers will dance over like goblins on a grave. (Heat is radiated back from the atmosphere to the hotter surface, at least mathematically, but net heat transfer still preserves the second law of thermodynamics. Good absorbers also, by definition, are good emitters, and most of the energy emitted to space is done by the greenhouse gases, but it's still true that they "block" or shield it by radiating in all directions, including down; don't call it reflection.)

Hayden is right that there's not a big spectral band where CO2 can really play a role in the infrared. Only about 6% of the outgoing radiation is available to take part in this process (according to those hacks at NASA anyway). Most of the important radiative processes in the atmosphere involve water vapor, but at wavelengths from about 6 to 13 ?m, water is transparent, and that is where carbon dioxide absorption matters most. Here's a typical atmospheric absorption spectrum at infrared wavelengths (from astronomy sources, with no dog in this fight). Carbon dioxide has an absorption band in the middle of this spectral "window," nabbing about 40% of the radiant energy that has a wavelength near 12.5 ?m. Hayden makes a lot of noise about the saturation effect of CO2, harping that at some point, only so much light can be absorbed by the stuff, but the band 12.5 ?m is definitely not swamped. In fact, the exponential behavior of light absorption means that at low starting concentrations, the effect of increasing the amount of absorber is very pronounced, but at relatively high concentrations, when most of the radiation has been scavenged already, adding more material doesn't do anything extra. The transmission given in the figure is at known CO2 concentration (about 360 ppm, averaged roughly over MLO's sampling time), and it's easy to estimate what a 15% increase will get us, about 1-2% percent. A 30% increase would be about 5% more energy absorbed in that small portion of the spectrum.


At the poles, another 10% of incident solar radiation is reflected off the ice, and although this seems like another small number to work with, it also affects the surface temperature. When there is less ice, there is more solar absorption at the bare surface, increasing the surface temperature slightly, which melts the ice. Increasing temperature also causes enhances the CO2 level in the atmosphere, since the solubility of the stuff in the oceans goes down (and more carbon in the atmosphere causes the temperature to further increase, etc.). When I look at the CO2 and temperature data from ice cores, the salient feature I notice is that there are two relatively stable values near which the CO2 concentration (and temperature) variation is usually restricted. On the earth, at least for the past 400,000 years, it's a good hypothesis that the limiting values correspond to the limiting values of those adjustable parameters, that is, there is only so much ice to melt or freeze, and the effect of carbon in the atmosphere can only be so big. The reason it pushes toward the extreme values may well be that they're stable compared to intermediates. (I tap vague memories of control theory, and think it looks like a two-state oscillator, an often-cited system which can switch suddenly between two (or many) different periodic behaviors. Follow the link at the end, and tell me if you agree.) The in-between points of systems like this are generally unstable, and the tendency to jump between one extreme or another is due to a sensitivity of the system to its various parameters. Plausibly, the subtle orbital mechanics of the Milankovitch cycles can nudge the climate behavior to one limit or the other--it doesn't seem to be an exact match (which bugs climatologists), but the periodicity looks right.


The upper limit of this cycle is probably not due to optical saturation of the 12.5 ?m band, but it may be a case of running out of carbon to spread around the system. Hayden makes a really annoying point that CO2 levels in the Jurassic period were far higher than they are now, neglecting to mention that the temperatures were a whole lot higher then too. On a geological scale, the earth is now in a cold period, one of a few dips down from what has otherwise been a fairly steady average temperature through Deep Time. Atmospheric carbon, which is also at a low, influences this, and so does the position of the landmasses (continents at the poles to support glaciers matter), and, likely, the population and diversity of biota. (The relation between the CO2 level (high) and temperature (low) way back in the late Ordovician is interesting and the explanations are shaky. It's a much better response to climate change arguments than anything Hayden actually bothered to look up.) To the extent that maximum optical absorption by atmospheric CO2 can be taken to set the upper stable limit of earth's temperature, then we're still well short (ten average degrees) of it, and it'll take more than a few tens of percent concentration increase. I would be confident that we're only merely riding out a peak of the warming behavior that's been repeating for 400 kiloyears if it weren't for the fact that we've resurrected a good deal of carbon from previous geological eras and put it back into the climate system, and we will continue to do so until it's too hard to get. It's a pretty ballsy bet.

There are a number of sources and sinks for both carbon dioxide and energy that occur across the planet, and for sure, they vary with latitude and surface features. Pointing this out is not a refutation of climate models, but Hayden gives it a shot anyway. Correlation is certainly not the same as causation (and even Al Gore chose his words carefully there), but often in complicated systems, various parameters influence one another, and keeping track of them all to estimate where they balance out is not only the right way to defeat oversimplification, it's exactly what a climate model is. When you find yourself smugly pointing out the shortcomings of the simple explanations, and then complaining that the detailed explanations have too many parameters, then it's safe to say that you're just being an asshole. It's true that more adjustable parameters gives you more room to fake the results, but Jesus, they're putting in real data to the extent they can, and always using known physics. Picking on the vernacular and pointing out "many" minor errors in a popular field that generates hundreds of papers a year is pretty fucking annoying too. Not all of them make it into Science.

Near the end of An Inconvenient Truth, Al Gore hopefully suggested activities that might cut away at carbon emission: conservation, sequestration, renewable energy resources. (Oddly enough, he doesn't want to renege on the highway system or the other entitlements of the American dream.) And here I regrettably join company with Howard Hayden. I don't think we'll ever manage to replace the stuff, and barring scarcity or a dramatic reduction in the human population, the world will never curb its carbon emissions. Still, Hayden stoops to speciousness even to diss the more tenuous dreams. Maybe there's not an ideal storage mechanism for electricity right now ("no mechanism" is obviously untrue) but it's something that's within reasonable ambitions of engineering. I am not any more pro-hydrogen than he is, but that's one potential storage mechanism right there. It's not so much that Hayden is flat wrong, it's that his dissent to climate change is dishonest. You don't need to drop $13.95 and half an hour on a shitty pamphlet to realize that of course, but this time I felt obligated.

*Also writing outside my field, here. Although I am a minor author on a tiny paper out there about scrubbing aerosols from exhaust streams. I suppose that puts me one up on Hayden in terms of climatological cred.

**Presumably the flux of energy from the core to the surface is small, and presumably tidal effects and so forth don't amount to much (except maybe every 10,000 years or so).

Free Reading:

  1. Good description and historical review of climate change from those godless hippies at the American Institute of Physics.

  2. CO2 and temperature in geological time. Really interesting stuff.

  3. Do climate cycles over 4000,000 years look like the behavior of a double-well oscillator? Learn about them here.

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