Intergenerational equity under catastrophic climate change

Aurélie Méjean (CNRS, Paris), Antonin Pottier (Centre d’Economie de la Sorbonne), Stéphane Zuber (Paris School of Economics - CNRS) and Marc Fleurbaey (Princeton University)

GPI Working Paper No. 5-2020, published in Climatic Change

Climate change raises the issue of intergenerational equity. As climate change threatens irreversible and dangerous impacts, possibly leading to extinction, the most relevant trade-off may not be between present and future consumption, but between present consumption and the mere existence of future generations. To investigate this trade-off, we build an integrated assessment model that explicitly accounts for the risk of extinction of future generations. We compare different climate policies, which change the probability of catastrophic outcomes yielding an early extinction, within the class of variable population utilitarian social welfare functions. We show that the risk of extinction is the main driver of the preferred policy over climate damages. We analyze the role of inequality aversion and population ethics. Usually a preference for large populations and a low inequality aversion favour the most ambitious climate policy, although there are cases where the effect of inequality aversion is reversed.

Other working papers

Moral demands and the far future – Andreas Mogensen (Global Priorities Institute, Oxford University)

I argue that moral philosophers have either misunderstood the problem of moral demandingness or at least failed to recognize important dimensions of the problem that undermine many standard assumptions. It has been assumed that utilitarianism concretely directs us to maximize welfare within a generation by transferring resources to people currently living in extreme poverty. In fact, utilitarianism seems to imply that any obligation to help people who are currently badly off is trumped by obligations to undertake actions targeted at improving the value…

Against the singularity hypothesis – David Thorstad (Global Priorities Institute, University of Oxford)

The singularity hypothesis is a radical hypothesis about the future of artificial intelligence on which self-improving artificial agents will quickly become orders of magnitude more intelligent than the average human. Despite the ambitiousness of its claims, the singularity hypothesis has been defended at length by leading philosophers and artificial intelligence researchers. In this paper, I argue that the singularity hypothesis rests on scientifically implausible growth assumptions. …

Three mistakes in the moral mathematics of existential risk – David Thorstad (Global Priorities Institute, University of Oxford)

Longtermists have recently argued that it is overwhelmingly important to do what we can to mitigate existential risks to humanity. I consider three mistakes that are often made in calculating the value of existential risk mitigation: focusing on cumulative risk rather than period risk; ignoring background risk; and neglecting population dynamics. I show how correcting these mistakes pushes the value of existential risk mitigation substantially below leading estimates, potentially low enough to…