VOX  CEPR Policy Portal

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.

At the peak of the Global Crisis, the US dollar appreciated and US Treasury yields fell, suggesting that foreign investors were purchasing US assets in general. Actually, they were fleeing only into short-term Treasury bills. This column discusses recent research showing that there are indeed no securities which are consistently a safe haven across different crisis episodes – not even US assets. However, a peculiarity of the US securities is that foreign investors do not necessarily ‘run for the exit’, even when a crisis has its epicentre in the US.

Stabilisation policy should focus on the frequencies consumers care most about. This column presents evidence from stock-market returns suggesting that consumers are willing to pay the most to avoid – and are therefore most concerned about – fluctuations that last tens or hundreds of years. Modern macroeconomic theory tends to view the role of monetary policy as smoothing out inflation and unemployment over the business cycle. The authors’ findings suggest that resources would be better spent on policies that smooth out longer-run fluctuations.