Anthropogenic climate change poses a threat to all people and governments, but the response to that threat varies enormously across countries. Some adopt politically costly and economically challenging climate change mitigation policies, while others deny that climate change is occurring. Why do...

We present a dynamic model of social network formation in which a fixed number of agents interact in overlapping social groups. We derive several results on the formation of links in such networks, including results on the degree distribution, on comparative statics relating degree and group...

This paper extends the gross substitutes and complements (GSC) framework of Sun and Yang (2006) to a more general substitutes and complements structure. We show that competitive equilibrium with indivisible goods exists under significantly weaker, easily checkable, and interpretable conditions....

Lemoine and Rudik (2017) argue that it is efficient to delay reducing carbon emissions, because there is substantial inertia in the climate system. However, this conclusion rests upon misunderstanding the relevant climate physics: there is no substantial lag between CO2 emissions and warming,...

Mineral and material commodities are essential inputs to economic production, but there have been periodical concerns about mineral scarcity. However, there has been no systematic recent study that has determined whether mineral commodities have become scarcer over the longer run. Here we...

The extent to which natural capital can be substituted with manufactured or human capital in production is a key determinant of the possibility of long-run sustainable economic development. We review empirical literature pertaining to the degree of substitutability between natural capital and...

We show how frictions and continuous transfers jointly affect equilibria in a model of matching in trading networks. Our model incorporates distortionary frictions such as transaction taxes, bargaining costs, and incomplete markets. When contracts are fully substitutable for firms, competitive...