We examine whether returns to capital are higher for farmers who borrow than for those who do not, a direct implication of many credit market models. We measure the difference in returns through a two-stage loan and grant experiment. We find large positive investment responses and returns to...

This paper demonstrates how three important results in environmental economics, true under mild conditions in closed economies, are false or need serious amendment in a world with international trade in goods. Since the three results we highlight have framed much of the ongoing discussion and...

Climate modelers have recognized the possibility of abrupt climate changes caused by a reorganization of the North Atlantic's current pattern (technically known as a thermohaline circulation collapse). This circulation system now warms north-western Europe and transports carbon dioxide to the...

Integrated assessment models have become the primary tools for comparing climate policies that seek to reduce greenhouse gas emissions. Policy comparisons have often been performed by considering a planner who seeks to make optimal trade-offs between the costs of carbon abatement and the...

The paper develops a general methodology for analyzing policies with path-dependency (hysteresis) in stochastic models with forward looking optimizing agents. Our main application is a macro-climate model with a path-dependent climate externality. We derive in closed form the dynamics of the...