Closing borders has always been a typical reaction to pandemics in the history of humanity, and the responses to Covid-19 mark no difference. Initiatives to limit the diffusion of the virus has put the closure of national borders under the spotlight worldwide. However, national scale offers a...

We study the effect of leadership in an experimental threshold public "bad" game, where we manipulate both the relative returns of two investments (the more productive of which causes a negative externality) and the extent to which the gains from leadership diffuse to the group. The game...

Three gaps in the Kyoto Protocol most badly need to be filled: the absence of emission targets extending far into the future, the absence of participation by the United States, China, and other developing countries, and the absence of reason to think that members will abide by commitments. To be...