Global Warming?

Ordinarily, I try to refrain from commenting on matters on which others far better qualified than I have already commented at greater length and with far greater authority. Hence, the low volume of this blog.

For global warming, I ask your forgiveness for making an exception. My only excuse is that I keep getting asked by friend and foe on my views on the issue and concluded it would be useful to set them out in one place for future referral. If you, my gentle reader, already have a basic familiarity with the subject—i.e., one exceeding that of television newscasters and most newspaper reporters—nothing herein will come as surprise to you and I can lay claim to no authority to override the considered judgment of anybody with such familiarity. You can skip this entry without loss. Yet, the complementary set of the general population seems to be sufficiently substantial—and might even have an overlap with my small readership—that somebody might profit from reading what follows.

The following facts are, to the best of my knowledge, not in serious dispute:

1. The concentration of greenhouse gases, including most significantly CO₂, in the earth's atmosphere has increased substantially since the beginning of the industrial era (ca. 1850). There is no plausible alternative explanation for this phenomenon other than human activity and human activity is a plausible explanation for this increase.
2. All plausible projections of future human activity not involving the extinction of the species, massive deindustrialisation, or similarly dramatic events show that greenhouse gas concentrations in the atmosphere will continue to increase over the course of this century.
3. An increased concentration of greenhouse gases in an earth-like environment will etceteris paribus tend to increase temperatures. The theoretical basis for this effect was explained more than a century ago and has been verified experimentally in controlled environments a countless number of times, both before and after the theoretical basis was understood.
4. In an environment like the whole earth, this increased concentration of greenhouse gases will exert an upward pressure on temperatures. There are countervailing effects which will tend to counteract this upward pressure, but there is no reason to doubt that on net human activity has and will continue to increase global temperatures.

In short, there is very good reason to believe that human activity has resulted and will result in greenhouse gas emissions that will tend to warm the planet. But that does not settle the important question: By how much? To answer that question requires scientific knowledge and competence far beyond mine and depends on models so complex that even the most competent scientific answers are subject to doubt and prone to error.

Normally, one would nevertheless act on the basis of the best estimates of the most competent scientific authority. Unfortunately, both the public statements and the revealed private statements of several of these scientific authorities have revealed a powerful bias towards the apocalyptic. This, in addition to the inherent complexity of the subject, should temper reliance on the scientific consensus in this case. Their estimates are not only subject to inevitable random error, but there is strong basis to suspect they are biased upward. And this is to say nothing of the substantial interest of several powerful non-scientific groups—including the renewable resource industries looking for business, third-world governments looking for handouts, and reporters looking for dramatic story lines.

Yet, let's assume that the estimates of the better of these authorities, such as the Intergovernmental Panel on Climate Change, are in broad outlines correct: Unless drastic action is taken, by the end of the century the earth's mean temperature will have increased by several degrees centigrade and sea levels will have risen by several feet.

But even if these predictions are accurate, the drastic measures called for to combat climate change are, in my opinion, not justified. Their cost—trillions of dollars and close to a deindustrialisation of the advanced world—would exceed their benefits:

1. The predicted change in temperature is well within the experience of modern homo sapiens sapiens and all other currently extant species. We have survived larger temperature swings due to other reasons and it seems unlikely that a richer, and therefore more resilient, society could not survive them with only comparatively minor inconvenience. Catastrophe such as mass extinctions, in particular of humans, are therefore extremely unlikely to result if nothing is done.
2. Even within the present, the predicted change in temperature is far smaller than the difference in average temperature between large, rich areas of even the continental United States. Temperatures in Atlanta, Phoenix, and Los Angeles are about as compatible with advanced modern comfortable human conditions as those in Boston, Minneapolis, and Seattle. Yet, the predicted temperature changes are smaller than the differences in average temperature between these cities.
3. Similarly, with respect to the rise of sea levels: With much less advanced technology, we have dealt with the rise and fall in sea levels without measures anywhere near as drastic as proposed by the climate change apocalyptics.
4. While climate change of the predicted magnitude would have real and substantial costs, it also would have real and substantial benefits. For example, increased temperatures would make the northern U.S., Canada, the enormous area of Siberia, and others, more conductive to human habitation and cultivation than they currently are. In addition, the concentration of the principal greenhouse gas CO₂ is one of the main limiting factors of plant growth—the atmosphere is where plants get most of the carbon needed to produce the complex carbohydrates for which we rely on them. So increased CO₂ concentrations will tend to make the world more fertile, not less. In fact, increased growth of vegetation is one of the countervailing factors to the CO₂-induced global warming.

All that said, if there was a costless (or, at least, cheap on the trillion-dollar scale) way to stabilize greenhouse gas concentrations of the atmosphere, I would favor it. This would reduce both the real costs of adjustments to higher temperatures and avoid the small, but not non-existent, risk that the consensus estimates of the magnitude of the global warming effects are substantially low and the corresponding real costs much larger. Yet, no cost-effective ways to control greenhouse gas levels have even been broadly proposed, much less received serious consideration by those in power (i.e., the world's governments and their various supra-national bodies).

In sum: Yes, global warming is very likely real and human induced. And, no, we should not embrace any of the currently popular approaches to eliminate it.