For reasons I have discussed in earlier posts , I am skeptical of the claim that global warming on the scale suggested by the IPCC projections is a serious problem that needs to be dealt with. In this post, I want to look at the other side of the problem. If one accepts the conventional view that it is a serious enough problem to justify the cost of the sharp reduction in the use of fossil fuels needed to substantially reduce it, can it be done?The reason I suspect it cannot is that preventing global warming faces a public good problem at several levels. Consider first the individual level. One might argue that if global warming is going to make me worse off, that is a reason for me to reduce my use of fossil fuels in order to prevent it. The problem is that although it is a reason, it is a very weak reason, because I would be bearing all of the cost—driving less, or being colder in winter and hotter in summer, or paying more to get my electricity from solar power instead of from natural gas—while receiving only a tiny fraction of the benefit. As with other public goods, one would expect it to be underproduced and, since this is a public good for an enormous public, drastically so.One popular solution to a public good problem is to have the good produced by government. Have the government hold down the production of CO2 by a carbon tax or a cap and trade system, subsidize the development of technologies for recyclable power, and in various other ways force its citizens to modify their behavior to reduce global warming.One problem with this solution is that we have no good way of making a government act in the interest of those it rules, in part due to another public good problem. Anything I do to make government do the right things—figuring out which politician supports good policies and voting for him or contributing to his campaign, writing books or op-eds defending good policies and criticizing bad—is itself producing a public good for a large public, since almost all of the benefit of good policies goes to other people. Public goods, especially for large publics, are underproduced, which explains why many voters—about half of them, judging by the highly unscientific experiment of asking students in classes I teach—do not even know the name of the congressman who represnts them, and almost no voter knows enough about all of the relevant issues to have a sound basis for deciding how to vote. That outcome is referred to in the public choice literature as rational ignorance. It is rational to be ignorant when information costs you more than it is worth to you.If we have no way of making government consistently act in the national interest, we cannot count on government action to deal with global warming, even if it is in our interest to do so. And even if we did have a reliable way of controlling our government, we would still face a second level of public good problem. Controlling global warming is a public good not only at the individual level but at the national level, since if the U.S. holds down its emission of CO2, any benefit is shared with all other countries, whether or not they hold down theirs. Hence even a U.S. government that did act in the interest of its population might choose not to deal with global warming unless it could somehow arrange for most other countries to do so as well. Such an agreement among many beneficiaries of a public good is hard to arrange. It is even harder when, as in this case, the benefits are very unevenly distributed. Even if global warming produces net costs, which for the purposes of this post I am assuming, the costs to some countries will be larger than to others and some countries, most obviously in cold regions, will probably benefit.I have just offered reasons, at several levels, why nothing will be done to prevent global warming, even if it is worth preventing. Readers may reasonably ask how I can explain the fact that things are being done. The U.S. House passed a cap and trade bill some years ago, although it never made it through the Senate, and it looks as though there will be renewed attempts to get a carbon tax or something similar in the near future. The current administration has subsidized a variety of activities, such as biofuels and the development of electric automobiles, on the theory that they reduce global warming. Similar policies have been employed by a number of other countries, many of which committed themselves some years back to specified future reductions in carbon emissions.The answer is that while such policies are not worth doing, politically speaking, as a way of reducing global warming, they may be politically profitable in other ways. A loan guarantee to a company whose investors support the current administration, for instance, is a private good, or a public good with a very small public, from the standpoint of those investors, and one they will be willing to pay for in campaign donations or other ways of rewarding the politicians responsible for it. A carbon tax provides a new way of getting money into the hands of government, where it can be used to buy votes or reward supporters. Cap and trade, along the lines of the actual bill passed by the House, generates valuable assets—permits permitting the emission of a set amount of carbon dioxide. Those assets can be, in the House bill were, allocated to politically favored groups. In all of these ways, the campaign against global warming provides rhetorical support for politicians doing things they would like to do, but things that, absent that support, might cost them votes.Consider as an analogous case Obama’s stimulus program. Very likely Obama believed his own rhetoric, believed that it would bring down unemployment. But supposed he didn’t. As long as other people believed it, the stimulus made political sense for him, since it gave him a convincing excuse to spend large amounts of borrowed money. If he didn’t believe it he had to worry a little about the failure of unemployment to come down as predicted—but, as the most recent presidential election demonstrates, that problem can be overcome. He succeeded in getting reelected by a comfortable margin, despite the striking difference between what he predicted and what happened.