Essais sur des questions internationales en économie des ressources naturelles

This thesis consists of three essays on international issues in natural resource economics. The first essay proposes a spatial model of trade in exhaustible resources and emphasizes the role of geographical size and transport costs in the determination of trade patterns. The second essay considers the rent-extracting tariff in a spatial (more general) framework in which the importing country can be simultaneously a producer and an importer of the resource, a feature which is not possible in the traditional trade model, where countries are assumed dimensionless. The third essay tackles the issue of property rights in maritime zones and examines the allocation of a population of fishermen between productive and unproductive activities in a coastal community.  The first chapter proposes a model of trade in exhaustible resources that explicitly accounts for the fact that countries have different geographical sizes while resource sites and their users are spatially distributed, even within a country. Using a spatial model à la Hotelling, we examine the evolution over time of the pattern of trade between two countries (or regions) which differ in terms of their technology, their geographical size, and their endowment of some nonrenewable natural resource. The model emphasizes the importance of geographical size in determining trade patterns besides the traditional explanations of comparative advantage and factor endowments. Indeed, three forces influence the direction of international trade in the presence of transport costs. The analysis fundamentally differs from other contributions in the natural resource literature because it emphasizes the importance of geographical size and of transport cost relative to other factors in the determination of the equilibrium resource flows. The unit cost of transport is shown to play a decisive role in determining whether the international asymmetry in terms of geographical sizes of countries has a greater influence than other factors on the equilibrium pattern of trade. The chapter also discusses the regional character of trade which has been observed for some resources such as iron ore and bauxite.  Most findings in the literature on tariff and exhaustible resources have been derived under a serious abstraction. Indeed, virtually all contributions on that issue have assumed that no stocks of the resource are available within the importing country's borders and therefore the importing country is not itself a producer. Reality is in fact quite different: there are many instances of countries that are simultaneously importers and producers of a natural resource. The second chapter makes use of the spatial trade model of chapter one to depart from the usual assumption and allow the importing country to have access to a stock of the resource of its own and to determine simultaneously the optimal tariff and the rate of depletion of its own stock. The optimal tariff is shown to increase at the rate of interest and is therefore nondistortionary. Moreover, the optimal tariff captures all the rent if the exporting country gets no utility from consuming the resource.  Allowing the exporting country to consume the resource restricts the ability of the importer to capture all of the foreign rent. The presence of resource deposits in the importing country reduces the available rent to foreign producers and, in essence, reinforces the ability of the importer to capture the foreign rent. In effect, the initial tariff is shown to be a decreasing function of the initial resource stock in the importing country. The essay also discusses the time consistency of the open-loop tariff.  The third chapter examines how agents in a coastal community allocate effort between productive (fishing) and unproductive (piracy) activities. The allocation of population between fishing activity and piracy attacks is determined endogenously as a consequence of the occupation choice. We prove the existence of multiple equilibria and emphasize the possibility of a piracy trap, that is a steady state equilibrium where part of the population is engaged in piracy acts. The chapter offers an explanation for the significant increase in piracy attacks in the Gulf of Aden in the recent years. The chapter also discusses different schemes in combating piracy and highlights the crucial role of property rights.

Keyphrases: Spatial model à la Hotelling, Trade flows, Geographical size, Transport costs, Tariff, Oil rent, Differential game, Property rights, Piracy trap, Rent-seeking