Marion Dupoux defended her PhD thesis entitled "Structure of preferences, decision-making and the environment: theoretical and experimental approaches", on January 16th, 2017.
Climate change encompasses a large range of impacts such as extreme climatic events, biodiversity losses or deforestation. These impacts are very heterogenous across countries. Additionally, countries distinguish one from another according to their preferences and/or their context (income and environmental quality levels). Before any implementation, projects which entail both economic and environmental impacts are evaluated. The main tool used for projects
appraisal is the cost-benefit analysis. It relies on the way (objective) quantities are accounted for and the way the environment is valued via the individual willingness to pay and over time via the discount rates. The two latter elements are based upon preferences and the context of decision.
This thesis aims at providing insights on the (objective and subjective) determinants of the heterogeneity of project evaluations. At first, I analyze how (objective) quantities are incorporated in the cost-benefit analysis. The first main chapter deals with the way cost-benefit analysis is affected by the time distribution of impacts considered. Through the example of land use change from biofuel production, I find that decisions regarding projects with non-constant
environmental impacts rely on distorted net present values, which may result in the implementation of actually non-desirable projects or the non-implementation of actually desirable projects. This work is both theoretical and numerical.
Second, I investigate the role of the structure of preferences, i.e. whether private goods and environmental goods are substitutable or complementary in providing utility, on individual decision-making in an individual framework and a collective framework. At the individual level (second main chapter), we develop a single theoretical model which allows either for substitutability or complementarity depending on the context (income and environmental quality). It results that the income elasticity of willingness to pay can be negative in contexts of between-goods substitutability, which contrasts with usual frameworks which only allow for positive income elasticities (thus the environmental good can never be inferior but is always normal). Our framework also affects the way consumption and environmental quality are discounted, which is all the more relevant in the context of income shocks. At the collective level (third main chapter), we use an experimental approach to analyze the effect of the interaction between individuals with different structures of preferences on contributions to the public good. It results that perfect substitutability is associated with more free-riding than complementarity. However, an aversion to advantageous inequality also emerges from individuals whose preferences underlie perfect substitutability towards those whose preferences are based on complementarity.
These results suggest that the structure of preferences, often overlooked, plays a major role regarding the way individuals value the environment, thus more globally regarding decisionmaking towards the environment.
Nicolas Legrand defended his PhD thesis entitled "Revisiting the competitive storage model as a tool for the empirical analysis of commodity price volatility" on Monday November 21th, 2016.
This thesis proposes an empirical and theoretical analysis of commodity price volatility using the competitive storage model with rational expectations. In essence, the underlying storage theory states that commodity prices are likely to spike when inventory levels are low and cannot buffer the market from exogenous shocks. The prime objective pursued in this dissertation is to use statistical tools to confront the storage model with the data in an attempt to gauge the empirical merit of the storage theory, identify its potential flaws and provide possible remedies for improving its explanatory power.
Gaspard Dumollard defended his PhD thesis entitled "Gestion en futaie régulière d'une forêt à plusieurs classes d'âge en présence d'un risque de tempête", on December 2nd, 2016.
The storm risk has a strong impact on forest management, directly through the damages a storm can cause and indirectly through induced precautionary behaviors.
This PhD thesis addresses the issue of even-aged forest management with multiple age-classes in presence of a storm risk and when the producer has recursive preferences. Unlike expected utility preferences, recursive preferences distinguish between risk aversion and intertemporal preferences.
Simon Bordenave defended his PhD thesis entitled "Essai sur les conséquences environnementales de la recherche et développement sur les variété agricoles", on December 8th, 2016.