Yes, I would like to receive periodic updates and information via e-mail from Commentary.

Recipient Addresses:

Separate each address with a comma.

Your E-mail Address: Message:

In 1906 the Swedish chemist Svante Arrhenius published a popular book speculating on the origins of the earth and of life upon it. (An English translation, Worlds in the Making, appeared in 1908.) In a nutshell, Arrhenius proposed that the solar system was born of a collision between cool stars, with the sun and the planets forming from the resulting nebular debris. The planets, he thought, were then seeded by living spores that had been propelled through the cosmos by electromagnetic radiation.

Unfortunately for Arrhenius, few of these ideas ever achieved wide currency, and most of them were considered far-fetched even at the turn of the last century. One, however, has lately experienced something of a revival: the notion that the earth’s climate is maintained within bounds that are favorable to life by the concentration of carbon dioxide (CO₂) in the atmosphere. As early as 1896, Arrhenius had proposed that surface temperatures rise in proportion to atmospheric CO₂, which absorbs radiated heat that would otherwise escape into space. Noting that CO₂ can be generated by the burning of coal, Arrhenius predicted that the growth of industry might eventually result in a warmer planet (in modern terms, this would be called “anthropogenic forcing”)—a salutary outcome from a Scandinavian point of view, since a more temperate climate would likely be a boon to agriculture in the North.

This “greenhouse effect” is the cornerstone of the contemporary notion of global warming.¹ A hundred years after Arrhenius wrote, the concentration of CO₂ in the atmosphere has already nearly doubled, and the earth’s surface is on average about 0.6°C warmer—enough to convince many scientists and laypeople that Arrhenius was right at least about this. In 2001, the official estimate of the Intergovernmental Panel on Climate Change was that we should expect a warming of about 3°C, give or take a few degrees, in the decades ahead.

But today’s prophets of climate change are not quite so sanguine as Arrhenius about the prospect of anthropogenic forcing. This is because, according to some models, even a relatively small rise in global mean temperature would result in dramatic changes in local climate patterns. While climate modelers generally agree that farmers in subarctic latitudes will benefit from warmer summers and milder winters, their forecast for the rest of the planet approximates the apocalypse: famine, drought, hurricanes, floods, mass extinctions—the list goes on. Most of these calamities, said to be of such a scale that they could threaten the viability of human civilization, are predicted to result from changes in weather patterns that would follow from rising temperatures in the oceans and the lower atmosphere.


The earth’s climate is an extraordinarily complex system, and most climatologists would probably concur that local perturbations cannot be foretold with precision. But given the magnitude of the prospective problem, many pundits and policymakers—with the backing of the scientific establishment—have become less interested in improving our understanding of climate change than in pressing for an immediate solution. By this they mean somehow reducing (or at least stabilizing) the concentration of CO₂ in the atmosphere.

This is a difficult proposition, to say the least. About 70 percent of electricity in the United States is generated by the combustion of fossil fuels, mostly coal; our transportation network, which accounts for about a quarter of our greenhouse-gas emissions, is almost entirely dependent on petroleum. The picture in the rest of the world is not much better, as economic pressures dictate the construction of new coal-fired power plants not only in China and India but also in Germany and Eastern Europe. Despite all the fanfare surrounding Russia’s ratification of the Kyoto Protocol in November 2004, bringing the treaty into force, most experts agree that, because of relatively modest emissions targets, allowances for international trading of carbon credits, and the exemption of major polluters like China, it will have no discernible impact on global CO₂ emissions.

Nevertheless, as the intellectual class has increasingly become convinced of the reality of man-made climate change—recent “converts” range ideologically from Gregg Easterbrook of the liberal New Republic to Ron Bailey of the libertarian Reason—environmentalists have correspondingly stepped up their efforts to build public support for some sort of action. The media now regularly proclaim the impending reality of climate change and encourage alarm. ABC News, offering not so much as a bow toward a scientific approach, recently asked viewers to submit stories about “global warming” in their own communities. Even the July 2006 issue of Condé Nast Traveler, not generally known for coverage of science and technology issues, includes tips for travelers who feel guilty about the damaging emissions generated by their airplane flights.

Among the more serious efforts to sway the debate are two new books, Tim Flannery’s The Weather Makers: How Man Is Changing the Climate and What It Means for Life on Earth² and Elizabeth Kolbert’s Field Notes from a Catastrophe,³ along with Al Gore’s much ballyhooed film, An Inconvenient Truth. Each of these presents a more or less comprehensive view of the scientific case for global warming, and describes in vivid detail some of the changes already attributed to rising temperatures: melting permafrost in Alaska, the crack-up of the Larsen B ice shelf in Antarctica, thinning sea ice in the Arctic, fiercer and more numerous hurricanes in the Atlantic. And each suggests that the threat of global warming is supported by an overwhelming scientific consensus that, in their view, leaves absolutely no room for dissent.


The basic elements of the consensus are relatively easy to comprehend. Indeed, the three most important have already been mentioned. One is that surface thermometers have registered a global mean increase in temperature of about 0.6°C over the last century, give or take 0.15°C. This means that global temperatures are now higher than they have been in at least a thousand years, and perhaps since before the last major ice age. Likewise, atmospheric CO₂ has increased from preindustrial levels of around 250 parts per million by volume (ppmv) to around 378 ppmv, a level probably not seen since the Pliocene era, around 3.5 million years ago, when atmospheric CO² was higher for reasons that are basically unknown. There is little doubt, however, that at least some of the current increase is attributable to human activity.

So much for the data. The rest of what we “know” about global warming comes from intricate computer simulations, called general circulation models (or GCM’s), which make use of these data and innumerable other observations about the earth’s atmosphere in order to predict the effects of continuing increases in CO₂. Almost all the models forecast more warming, with the amount depending on various assumptions built into them. Although it is not clear from these results exactly why we should be alarmed—more on this later—Kolbert, Flannery, and Gore do their best to make sure that we are alarmed, enough to be willing to take drastic action. Each of them takes a slightly different rhetorical tack, but the ultimate message is always the same: we are on the verge of a catastrophe.

---

---

---

© 2008 Commentary Inc.