2020, Kornek, Ulrike, Edenhofer, Ottmar

One challenge in addressing transboundary problems such as climate change is the incentive to free-ride. Transfers from multilateral compensation funds are often used to counteract such incentives, albeit with varying success. We examine how such funds can change the incentive to free-ride in a global public-goods game. In our game, self-interested countries choose their own preferred course, deciding their voluntary public good provision, whether to join a fund that offers compensation for providing the public good and the volume of compensatory payments. We show that (i) total public-good provision is higher when those contributing are given more compensation; and (ii) non-participation in the fund can be punished if the remaining members decrease their public-good provision sufficiently. We then examine three specific fund designs. In the first, the compensation paid to each country is equal to the percentage of above-average total costs for public-goods provision. This design is best able to deter free-riding and can establish the social optimum as the equilibrium. In the second, the compensation paid to each country is a function of the marginal cost of their public-good provision. Here there are significant incentives to free-ride. In the third case, the monetary resources provided by the fund are fixed, a design frequently encountered in international funds. This design is the one least able to deter free-riding. © 2020 The Author(s)