Robert Stavins, 09 September 2019

Environmental economist Martin Weitzman passed away in August. This short intellectual biography and personal remembrance, by his long-time co-host of the Harvard Seminar on Environmental Economics and Policy, outlines how his contributions have advanced the thinking of environmental economists and policymakers on many fundamental issues, including policy instrument choice, discounting, species diversity, and environmental catastrophes. Across the board, the example of his rigorous and often ingenious work set high standards for theorising in environmental economics and thereby served to elevate the entire field.

Stefano Giglio, Matteo Maggiori, Johannes Stroebel, Andreas Weber, 29 November 2015

The optimal investment to mitigate climate change crucially depends on the discount rate used to evaluate the investment’s uncertain future benefits. The appropriate discount rate is a function of the horizon over which these benefits accrue and the riskiness of the investment. In this paper, we estimate the term structure of discount rates for an important risky asset class, real estate, up to the very long horizons relevant for investments in climate change abatement. We show that this term structure is steeply downward-sloping, reaching 2.6% at horizons beyond 100 years. We explore the implications of these new data within both a general asset pricing framework that decomposes risks and returns by horizon and a structural model calibrated to match a variety of asset classes. Our analysis demonstrates that applying average rates of return that are observed for traded assets to investments in climate change abatement is misleading.

Events

CEPR Policy Research