Читать книгу Geoengineering - Gernot Wagner - Страница 15

Economics 101 is clear about the cause of excess CO₂ emissions in the atmosphere: the benefits of emitting CO₂ are privatized, while the costs of one’s pollution are largely socialized. The solution is self-evident: price CO₂ at the difference between the marginal private and social cost. Arthur Pigou suggested as much in 1920, in his case for rabbits overrunning a communal meadow.⁴ The diagnosis is the same.

The term for this Economics 101 principle: the free-rider effect. It is in nobody’s immediate self-interest to go first and bear the costs of mitigating CO₂. That goes for individuals and companies as much as it does for countries. Why commit to something if others won’t?

Economists arguably make too much of a deal out of this one element of the analysis. Political Economics 101 immediately points to vast vested interests as the true hurdle for action. Even if politicians in one country are citing other countries’ lackadaisical climate policies as a reason for their own inaction, it typically comes down to domestic politics. In short, the free-rider effect may be overplayed. It clearly isn’t the full explanation of what is preventing steeper CO₂ cuts.⁵ But it surely is one part of the fuller picture.

Much as the free-rider effect implies too much CO₂ pollution, solar geoengineering is governed by the opposite fundamental forces. It’s not about motivating to act, it’s about stopping too much action. Call it the “free-driver” effect. Marty Weitzman and I coined the term in a Foreign Policy essay memorably titled “Playing God.” Weitzman later formalized the idea in a peer-reviewed economic paper.⁶ We were by far the first to recognize this fundamental property and to consider it important. As is so often the case with game-theoretic ideas, the first mention goes back to Nobel laureate Tom Schelling.⁷ Whatever its name, the fact that solar geoengineering is such a potentially powerful tool relative to its costs makes it a force to be reckoned with.