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Thursday, April 22, 2010


All of us, I can say with confidence, are aware of the debates about global warming, at least at the level of political dispute. The present state of the debate seems to be this: Most experts agree that human activities, including the burning of fossil fuels and the deforestation of large areas, are having the effect of raising the world's average temperature, with potentially far-reaching consequences for agriculture, the viability of coastal settlements, and so forth. A relatively small minority of experts disagree. Those who accept the judgment of the majority of experts conclude that the nations of the world should take deliberate and sometimes costly efforts to reduce carbon emissions; those who accept the minority judgment disagree. This then has become a signature left-right debate, with those on the left calling for immediate action and those on the right claiming that such action will have a disastrous effect on the profitability of capital. Everyone engaged in the debate seems to agree that the decision to control carbon emissions should depend on one's evaluation of the claim that carbon emissions are causing global warming. I should like to suggest that this is confused way of thinking. I offer these thoughts in the full acknowledgement that I am a complete tyro when it comes to the relevant science. My knowledge is limited to the reading of a few books [including a bizarre novel by Michael Crichton that is a thinly disguised polemic against the defenders of the global warming thesis]

There is no scientific disagreement about the well-established fact that the average temperature of the earth has varied considerably over the past several billion years. At one point, it appears that for several hundred million years the entire earth was covered with ice [the "snowball earth" thesis], and the Great Lakes, Finger Lakes, and other familiar geological formations are evidence of the periodic advance and retreat of glacial fields. There has even been a period of temperature fluctuation in the relatively recent historical past. Starting the the late 13th century, glaciers advanced in Northern Europe much farther south than their present location, with the result that the customary warm summers of Europe became unreliable. The last major glacial period, or ice age, ended not too long before the beginning of recorded history, perhaps twelve thousand years ago or a bit more.

During most of human history, changes in the earth's temperature, though they had an effect on the human population, by altering the location and extent of areas that were habitable, did not pose a major threat to humans because there were so few of them on the face of the planet. But in the past century or two, the human population has exploded, with two very important consequences. First, feeding the world's population now requires the industrialization of agriculture. Both the gross output and the year by year reliability of agricultural output is now essential to a population that is primarily urban and completely cut off from arable land or the activity of food production. Second, people have settled along vast stretches of low-lying coastal areas, not only in places like Bangladesh but also in North and South America and Europe. It would take only a relatively minor fluctuation in the earth's average temperature to produce horrendous disruptions both to the food supply and to those coastal settlements. Therefore, it is very much in the interest of the entire world that the temperature of the earth remain quite stable, neither rising nor falling more than a degree or two [which, contrary to one's intuition, is all by itself enough to produce important disruptions.]

Unfortunately, the evidence of the last several billion years makes it clear that the average temperature of the earth does not remain stable over long periods of time. Left to its own devices, the earth grows cooler and warmer all by itself.

So the consensus about the Global Warming controversy, it seems to me, is wrong. The crucial question is not whether carbon emissions are the cause of what appears to be a recent trend of global warming. The only relevant question is whether human activity can, in any way, be a contributing factor in the short-term determination of global temperature. I say "short term," because even if the earth is going to go through another major glaciation some time in the next ten or fifteen thousand years, which is to say a major global cooling, it makes an enormous difference to human beings how the earth's temperature changes in the next several centuries. A two or three century long period of global warming would be perfectly compatible with a thirty thousand year cycle of glaciation. From the perspective of geological time, such a minor variation would be insignificant, even though it might be catastrophic for us and the next fifteen or twenty generations to follow us.

So, it would be very useful to alter the terms of the current debate. Can human activity have a measurable effect on the earth's average temperature, regardless of the underlying causes of long-term temperature cycles? Can we figure out what that effect is? Are there things the world's population can do to tweak the temperature fluctuations so as to dampen potentially catastrophic short-term shifts?

These are the questions we ought to be asking. I am not competent to answer them, though I am impressed by the evidence that the answer to all three of these questions is Yes.


Noumena said...

It's a good point. It's one I've seen before, but very rarely; I think you're right about how the debate is usually understood.

And, in fact, I've seen some arguments against cap-and-trade and other efforts to limit CO_2 emissions that don't depend on denying (or, for that matter, affirming) AGW. The first depends on a premise that global warming is to a significant extent due to trends that we cannot sufficiently counteract, that is, that global warming is going to happen whatever we do. This argument, I think, is not especially compelling, although difficulties in modeling such a complex system as the global climate make more room for this case than one might think.

The second argues in cost-benefit terms -- in at least one instance literally, in terms of national GDP over the next century -- is that we can't afford to limit CO_2 emissions. That is, the economic hit we'll take from various cap-and-trade proposals is worse than the economic hit we'll take from just letting climate change happen and dealing with the effects. This argument strikes me as myopic in two ways. First, I can't think of a major public policy decision that was based on projections of GDP over the next century, and it's not clear why that's the appropriate basis in this particular case. Second, it's not wealthy, industrialized, `developed' countries that are going to suffer much from climate change (the Netherlands notwithstanding); we can afford to build levees, move cities, and tweak our agricultural system. It's poor, agriculturally-dependent, `undeveloped' countries that are going to suffer crop failure and environmental refugees. No ethically sound public policy should look exclusively at the effects of climate change on the US.

Robert Paul Wolff said...

That is an extremely interesting comment. Thank you for it. [By the way, I love the handle and the picture of Kant. You wouldn't consider changing your handle to ding an sich, would you?]

My untutored intuition is that you are right on both points, but I do not think this should be a litmus test of one's ideology. Nor should one approach these matters in a quasi-religious fashion, as many people do [Gaia, Mother Earth, etc]. These are difficult and complex matters of fact and judgment, shaped as well by genuine political questions -- see your observation that the impact of climate changes will be very different for different nations and groups of people. If the debate could proceed along these lines, it might be more fruitful.

Jim said...

Actually, it increasingly appears that any policy discussion about global warming issues will have to take in to account the increasing number of climate change refugees. As many Pacific Islander’s (among others) homes become literally submerged by the rising ocean level, they must relocate to higher, drier land. New Zealand and Australia have already begun to address this with regard to their immigration policies. Perhaps immigration reform proposed by the Obama Administration can include a plank acknowledging the growing incidence climate change refugees.

Robert Paul Wolff said...

A good point. You will really see some action if and when the runway at JFK in New York slides under water!

Ann said...

I welcome your attention to this issue. But I'm not convinced that "industrialized agriculture" is necessary, and may even contribute more to global warming than to food production, in terms of fossil fuel use in synthetic fertilizer, internal combustion farm equipment, and long distance well as impervious surfaces associated with urbanization.

Perhaps reversal of urbanization and restoration of traditional agricultural methods would be more sustainable in the long run.

At least this is a position of some few remaining indigenous peoples, as I understand it.

I welcome evidence, references, and comments on this particular issue.

Robert Paul Wolff said...

Ann, I would like you to think seriously about the quantitied of food needed to feed the entire world population, not just those capable of paying Whole Foods prices. I am serious. Try to figure out what would be required.

Ann said...

A tax on carbon (gasoline and petroleum) would raise the price of industrial food to be much higher than Whole Foods. It depends on how externalities are measured and assessed.

Noumena said...

Organic produce is more expensive than conventional produce mostly because organic agriculture is more labor-intensive than conventional agriculture and organic produce is heavily marked up (especially by stores like Whole Foods!). Conventional agriculture, however, is more capital-intensive (pesticides and fertilizers are expensive) and non-local agriculture has higher transportation costs than local agriculture. Local organic produce, bought directly from the farmer, can actually be only slightly more expensive than conventional produce shipped from California and Mexico. Further, organic agriculture is slightly less productive per hectare than conventional agriculture (92% is a pretty common number). But it's also significantly more effective than forms of low-intensity agriculture common in poor or `developing' countries. This sort of story is quite common if you do a little searching:

Kristina said...

This is a very interesting discussion indeed! I would like to add that the increase in the consumption of animal products is a huge factor in this. Significantly less food would have to be produced to feed the world if we reduced the amount of meat and other animal products that are being produced. The farm animal sector is the single largest anthropogenic user of land and the contribution of the animal farming industry to the emission of green house gases surpasses that of the entire transportation sector.

See here for a 2006 report from the UN Food and Agriculture Organization:

And here for another recent article on the topic:

Of course, there is a lot more evidence to be found, but these two reports give quite a good overview to start with.

Robert Paul Wolff said...

Kristina, that is an interesting line of attack. I am a committed fish and meat eater, although I eat much less meat than fish, but if one could really get the whole world to change over to tofu and beans and such, it would dramatically lessen the agricultural footprint on the world. If temperature change significantly alters world food priduction capabilities, that may become not a Yuppie choice but a necessity. I wouls still like to make boeuf bourguignonne once or twice a year, please.

Ann said...

Thanks for the comments and references!

The U.S. may be particularly wedded to cheap food because it does enable low wages.....Imagine what "slow food" would do to wages, the standard of living (not to mention the national waistline and rates of obesity), and/or profit rates! :-)