As world leaders gather in Copenhagen, climate change is again in the headlines. The science of the issue can get pretty incomprehensible pretty quickly. And the politics are clearly very ugly. Let’s not forget, however, that much of the economics is simple.
It’s an externality, stupid—so price it
Climate change is an “externality” problem. Individuals, firms, and, yes, governments, do not take full account of the harm that others suffer when they emit greenhouse gases. So they emit too much. And the best way to stop them doing this is to charge them a price for the carbon content of what they emit: a “carbon price.”
Admittedly, climate change is a particularly complicated externality. Since the damage will fall largely on future generations, the proper price depends very much on how we value their well-being relative to ours. The importance of such long-lived investments as power-stations, and the heavy sunk costs of investing in new technologies, mean that the carbon prices people expect in the future are even more important than the price now. And the fact that the world’s supply of fossil fuels is ultimately fixed means that the effect of carbon prices on total emissions is not as clear cut as it may seem.