Tuesday, July 31, 2007

Global Climate Change

Catching up on my reading after some recent travels, I notice an excellent symposium on "Global Climate Change" in the latest Economists' Voice, with contributions from Joseph Stiglitz, Sheila Olmstead and Robert Stavins, Kenneth Arrow, and Thomas Schelling. The first and the last were particularly interesting.

From Stiglitz, arguing for a global environmental tax on emissions:

The big advantage of taxation over the Kyoto approach is that it avoids most of the distributional debate. Under Kyoto, getting the right to pollute more is, in effect, receiving an enormous gift. (Now that pollution rights are tradeable, we can even put a market value on them.) The United States might claim that because it is a larger country, it "needs" more pollution rights. Norway might claim that because it uses hydroelectric power, the scope for reducing emissions is lower. France might claim that because it has already made the effort to go into nuclear energy, it should not be forced to reduce more. Under the common tax approach, these debates are sidestepped. All that is asked is that everyone pay the social cost of their emissions, and that the tax be set high enough that the reductions in emissions is large enough to meet the required targets.
Greg Mankiw has previously confirmed Stiglitz' entry into his Pigou Club. From Schelling, a good discussion of how to appreciate the uncertainty of projections of climate change:
In some public discourse, and in sentiments emanating from the Bush Administration, it appears to be accepted that uncertainty regarding global warming is a legitimate basis for postponement of any action until more is known. The action to be postponed is usually identified as “costly.” (Little attention is paid to actions that have been identified as of little or no serious cost.) It is interesting that this idea that costly actions are unwarranted if the dangers are uncertain is almost unique to climate. In other areas of policy, such as terrorism, nuclear proliferation, inflation, or vaccination, some “insurance” principle seems to prevail: if there is a sufficient likelihood of sufficient damage we take some measured anticipatory action.

At the opposite extreme is the notion, often called the “precautionary principle” now popular in the European Union, that until something is guaranteed safe it must be indefinitely postponed despite substantial expected benefits. Genetically modified foods and feedstuffs are current targets. (One critic has expressed it as, “never do anything for the first time.”) In this country the principle says that until a drug has proven absolutely safe it must be deferred indefinitely.

Neither of the two extreme principles—do nothing until we are absolutely sure it’s safe; do nothing until we are absolutely sure the alternative is dangerous—makes economic sense, or any other kind. Weigh the costs, the benefits, and the probabilities as best all three are known, and don’t be obsessed with either extreme tail of the distribution.

Kudos to Lawrence Goulder for putting this together as special editor.

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