NBER Publications by Bård Harstad

We analyze participation in international environmental agreements (IEAs) in a dynamic game where countries pollute and invest in green technologies. If complete contracts are feasible, participants eliminate the hold-up problem associated with their investments; however, most countries prefer to free-ride rather than participate. If investments are non-contractible, countries face a hold-up problem every time they negotiate; but the free-rider problem can be mitigated and significant participation is feasible. Participation becomes attractive because only large coalitions commit to long-term agreements that circumvent the hold-up problem. Under well-specified conditions even the first-best outcome is possible when the contract is incomplete. Since real-world IEAs fit in the incomplete con...

This article presents a sequence of simple and related models to analyze the strategic use of natural resources. Game theory is the natural tool for such an analysis, whether the resource is private or publicly owned, whether it is renewable or exhaustible, whether the game is static or dynamic, and whether or not the users can strategically invest in technologies. Equilibrium extraction is too large and comes too early for public resources, but the opposite is true for private resources. The effects add up nicely when the resource has both private and public-good aspects.

A conservation good, such as the rainforest, is a hostage: it is possessed by S who may prefer to consume it, but B receives a larger value from continued conservation. A range of prices would make trade mutually beneficial. So, why doesn't B purchase conservation, or the forest, from S? If this were an equilibrium, S would never consume, anticipating a higher price at the next stage. Anticipating this, B prefers to deviate and not pay. The Markov-perfect equilibria are in mixed strategies, implying that the good is consumed (or the forest is cut) at a positive rate. If conservation is more valuable, it is less likely to occur. If there are several interested buyers, cutting increases. If S sets the price and players are patient, the forest disappears with probability one. A rental m...

If a coalition of countries implements climate policies, nonparticipants tend to consume more, pollute more, and invest too little in renewable energy sources. In response, the coalition's equilibrium policy distorts trade and is not time-consistent. This paper derives conditions for when trading fossil fuel deposits increase efficiency. In isolation, a bilateral transaction may occur too often or too seldom compared to the optimum. However, when the market clears, the above-mentioned problems vanish, the first-best is implemented, and the coalition finds it optimal to rely entirely on supply-side policies, which are simple to implement in practice.