There is a tendency among libertarians to deny that the globe is warming or, more commonly now, that the warming is caused by human agency. I am not a scientist; I don’t know the truth about why glaciers are melting, but the rise in atmospheric carbon dioxide is suggestive.
And if the theory is correct, it is a problem for libertarians, whose theory of public life is based upon individual cooperation and markets. The weakness of market theory is externalities, the costs that the participants shove onto others. Some externalities are easier to deal with than others. When there is one big polluter, you can sue him to make him pay, or you can pay him, Ronald Coase style, to restrain himself. The liberal state can use its police power to protect public health in the case of many little polluters, as in the late-20th-century story of car owners and leaded gasoline.
But human-caused global warming, if the theory is correct, is caused by all 6.7 billion humans. It cannot be solved by one airshed or one country alone, and there is no international institution designed to deal with it. For dealing with it in a decentralized way, the incentives are wrong. The greater people’s economic success, the more combustion they tend to cause. The effects of warming are very slow, so there is an incentive to put off a solution to the next generation. Some people can be dragged by their social consciences to buy a Prius, but not most of them – and there is no guarantee that buying a Prius, riding the bus, using spiral light bulbs, recycling the garbage, etc., will actually do enough, or do anything measurable.
I don’t have the answer, and I think when I see it I’m not going to like it.