I’ve just finished William Ruddiman’s Plows, Plagues, and Petroleum. It argues that there’s a much farther-reaching human-caused global warming effect than we could have guessed. He claims that the deforestation (begun 8000 years ago) and irrigation farming (begun 5000 years ago) practiced by humans many centuries in the past had a significant impact on carbon dioxide and methane concentrations, which in turn kept the earth from moving back towards its next cyclic ice age. (That’s the “Plows” part.) Any disruption in this gradual upswing of heat-trapping gases was caused by serious pandemics, which took the lives of so many humans that the amount of land under cultivation dropped, and those farmlands went back to forests. (That’s the “Plagues” part.) And since 1850, we’ve burned so much fossil fuel that the gradual rise in greenhouse gases caused by humans has been replaced by an incredibly fast upturn. (That’s the “Petroleum” part.)

Ruddiman has an impressive scientific attitude towards his work. He couches it in terms of a mystery story, asking himself why, if the Milankovich hypotheses are correct, and if the observed orbital cycles of 23000 and 100000 years affect how much solar radiation the world receives, then why have things diverted from this combination of expectations over the last 8000 years?

It is truly hilarious that Ruddiman could become important to global warming skeptics. If anything, he is a solid, if unique, contributor to the claim that humans change their climate. He simply says that we did it far longer and earlier than we might have guessed.

My interest in this post, however, is his epilogue. Ruddiman tries hard to stay out of the political fight, and decries “extremists” on both sides. In fact, he thinks that global warming is a smaller problem, ultimately, than resource depletion. Consequently, Ruddiman is that rare bird who holds the following two beliefs simultaneously:

• Human-caused global warming is very real, even larger than usually claimed
• Global warming is not a crisis

If it isn’t a crisis, then, what does he think? Interestingly, he leaves value judgements for others. For instance, sea ice in the Arctic is diminishing and may well be gone soon. After discussing pro-industry and pro-Inuit/polar-bear views of the issue, Ruddiman says: “Both viewpoints have validity, and weighing all of the pros and cons is difficult.” (p.181) “[O]pinions about global warming will likely reflect the value systems that individual people bring to this issue.” (p.182)

Then comes his wisdom — wisdom which likely can only come from someone analyzing the value debate from the sidelines.

To reduce current and future greenhouse-gas emissions to levels that would avoid most of the projected future warming, draconian economic sacrifices would have to be enacted that almost everyone would find intolerable: much more expensive fuel for travel and heating, much lower/higher thermostat settings in houses and workplaces, and extremely costly upgrades (or total replacements) of power plants. The drag on the economy and on quality of life from such efforts would be enormous, and few citizens would stand for it. At this time, with current technologies, we simply cannot afford the effort that would be required to mitigate the main impact of global warming. (p.183)

Ahem. This reminds us that, for all the discussion of carbon trading, green building, wind and solar, public transit, and energy efficient light bulbs, down deep, none of this amounts to a hill of beans. Anything that even put a dent into the problem would need to be huge. And that dent wouldn’t necessarily avoid the whole problem.

One bit of word choice I object to, though it is correct in the prevailing economic sense. He states that the “drag” on “quality of life” would be “enormous.” Well. One might say that Bill McKibben’s work is the antidote to equating “quality of life” with “freedom from economic sacrifices”. Why is quality of life necessarily lower if energy use is drastically less? Why isn’t there a form of quality to be found in staying put, staying slow, declaring that you already have enough and you’ll be reducing from now on?