Suppose that there exists a positive (exogenous) probability that at each date of a possibly infinite future, the human species will disappear. We postulate an Ethical Observer (EO) who must solve an intertemporal welfare maximization problem under this kind of uncertainty, with preferences that...

Carbon budgets are a useful way to frame the climate mitigation challenge and much easier to agree upon than the allocation of emissions. We propose a mechanism with countries agreeing on the global carbon budget, while the decision to emit is decentralized at the country level. The revenue is...

Climate science indicates that climate stabilization requires low GHG emissions. Is this consistent with nondecreasing human welfare? Our welfare index, called quality of life (QuoL), emphasizes education, knowledge, and the environment. We construct and calibrate a multigenerational model with...

Whether or not to vaccinate one’s child is a decision that a parent may approach in several ways. The vaccination game, in which parents must choose whether to vaccinate a child against a disease, is one with positive externalities (herd immunity). In some societies, not vaccinating is an...

Mankind must cooperate to reduce GHG emissions to prevent a catastrophic rise in global temperature. How can the necessary costs of reducing GHG emissions be allocated across regions of the world, within the next few generations, and simultaneously address growth expectations and economic...