Frank Plumpton Ramsey Professor of Political Economy
There is a low but uncertain probability that climate change could trigger “mega-catastrophes,”
severe and at least partly irreversible adverse effects across broad regions. This paper first discusses the
state of current knowledge and the defining characteristics of potential climate change mega-catastrophes.
While some of these characteristics present difficulties for using standard rational choice methods to
evaluate response options, there is still a need to balance the benefits and costs of different possible
responses with appropriate attention to the uncertainties. To that end, we present a qualitative analysis of
three options for mitigating the risk of climate mega-catastrophes—drastic abatement of greenhouse gas
emissions, development and implementation of geoengineering, and large-scale ex ante adaptation—
against the criteria of efficacy, cost, robustness, and flexibility. We discuss the composition of a sound
portfolio of initial investments in reducing the risk of climate change mega-catastrophes.
Kousky, Carolyn, Olga Rostapshova, Michael Toman, and Richard Zeckhauser. "Responding to Threats of Climate Change Mega-Catastrophes." HKS Faculty Research Working Paper Series RWP10-008, March 2010.