We provide the planner's solution to a model where households learn from exogenous natural disaster arrivals about arrival rates and spend to mitigate future damages. Mitigation cannot be decentralized due to positive externalities from curtailing aggregate risks. First-best can be implemented...

Aging populations in advanced economies are placing ever-increasing demands on government spending in the form of old-age benefits. Economies that have promised substantially more benefits than they have made provision to finance are heading into a prolonged era of fiscal stress. Unresolved...

International environment and development agencies increasingly emphasize external cofinancing when selecting projects to fund. This paper considers whether the emphasis on cofinancing helps promote institutional objectives, or creates perverse and inefficient incentives. We present a model of...

We explore the principal trends that are shaping the future landscape of energy supply, demand, and trade. We take a long-term view, assessing trends on the time scale of a generation by looking 25 years into the past, taking stock of the current situation, and projecting 25 years into the...

This paper examines the association between episodes of large fiscal impulses (expansions and adjustments) and sustainable development indicators (prosperity, resilience, and inclusivity). We provide country studies of Chile, Poland, South Africa, and Thailand, examining the components of...

We view sustainability as a requirement that welfare should not be expected to decline over time. We impose this requirement as a prior constraint on the consumption-savings-investment problem, and study its implications for saving, risky investment, and the social discount rate. The constraint...

How does the sustainable level of consumption depend on productivity growth and the size and growth rate of the population? What is the effect of uncertainty over these growth rates? I address these questions using a model in which productivity and population growth are stochastic, and social...

Conservation programs in low-income countries often have dual goals of protecting the environment and reducing poverty. This article discusses the tension between these two goals in payments for ecosystem services (PES) programs. Participants who undertake a pro-environment behavior receive a...

We trace the linkages between the episodes of fiscal expansion and consolidation in 72 advanced and emerging and developing economies. The findings suggest that fiscal expansions are positively associated with economic growth, which in turn is positively linked with better sustainable...