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...

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...

Countries with high debt loads are vulnerable to an adverse feedback loop in which doubts by lenders lead to higher sovereign interest rates which in turn make the debt problems more severe. We analyze the recent experience of advanced economies using both econometric methods and case studies...

The global economy has a chronic shortage of safe assets which lies behind many recent macroeconomic imbalances. This paper provides a simple model of the Safe Asset Mechanism (SAM), its recessionary safety traps, and its policy antidotes. Safety traps share many common features with...

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...

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 develop a consistent and comprehensive theoretical framework for assessing whether economic growth is compatible with sustaining well-being over time. The framework focuses on whether a comprehensive measure of wealth - one that accounts for natural capital and human capital as well as...