Vincent Martinet

Multi-criteria dynamic decision under uncertainty: a stochastic viability analysis and an application to sustainable fishery management.

Managing natural resources in a sustainable way is a hard task, due to uncertainties, dynamics and conflicting objectives (ecological, social, and economical). We propose a stochastic viability approach to address such problems. We consider a discrete-time control dynamical model with uncertainties, representing a bioeconomic system. The sustainability of this system is described by a set of constraints, defined in practice by indicators - namely, state, control and uncertainty functions - together with thresholds. This approach aims at identifying decision rules such that a set of constraints, representing various objectives, is respected with maximal probability. Under appropriate monotonicity properties of dynamics and constraints, having economic and biological content, we characterize an optimal feedback. The connection is made between this approach and the so-called Management Strategy Evaluation for fisheries. A numerical application to sustainable management of Bay of Biscay nephrops-hakes mixed fishery is given.

Satisficing Versus Optimality: Criteria for Sustainability

Economic analysis addresses risk and long-term issues with discounted expected utility, focusing on optimality. Viability theory is rooted on satisfying sustainability constraints over time, focusing on feasibility. We build a bridge between these two approaches by establishing that viability is equivalent to an array of degenerate intertemporal optimization problems. First, we focus our attention on the deterministic case. We highlight the connections between the viability kernel and the minimum time of crisis. Carrying on, we lay out stochastic viability, turning the spotlight onto the notions of viable scenario and maximal viability probability. Our conceptual results bring the viability approach closer to the economic approach, especially in the stochastic case and regarding efficiency. We discuss the possible use of viability as a theoretical framework for biodiversity conservation, ecosystem management and climate change issues.

Lois de conservation économiques et développement durable.

In the economic literature, sustainability is often defined as the requirement of keeping something constant, or at least non-decreasing, along time (for example, consumption or utility). In this paper, we wonder under which conditions invariant quantities can be found along the optimal paths defined by the classical representation of an economy with an exhaustible resource. We use the Noether theorem to determine the conservation laws of dynamic systems. We examine under which conditions such invariants exist and how they can be interpreted as sustainability indicators.

Interactions between agricultural economics and environmental and resource economics in European research: Insights from the theory of non-renewable resources

Agricultural Economics and Environmental and Resource Economics are two fields which cross-fertilized each other. These interactions are expected to grow in the near future, as the sustainability of agriculture is challenged by the depletion of natural resources. In this article, we focus on three topics in natural resource economics: the resource curse, the sustainable development, and the green paradox. Insights from these topics are then used to discuss the future challenges to be addressed in agricultural economics. The literature on the resource curse examines the links between resource rent and economic development, and emphasizes that resource richness may jeopardize economic growth. The recent boom in agricultural commodity prices may lock developing countries in a poverty trap if the rent from agricultural products exports is not properly reinvested. The economics literature on sustainable development emphasizes that defining sustainability is a difficult task, and that there is not a unanimous sustainability criterion to be applied to agriculture. Here again, the question of capital depreciation and investment for future generations is central and calls for the valuation of the capital assets agriculture relies on. The literature on the green paradox questions the effectiveness of well-intended environmental policies and their possible counter-productive effects. Improperly defined policies, such as biofuel subsidies and mandate, or land use constraints aiming at preserving biodiversity, may result in more rapid resource degradation. (This abstract was borrowed from another version of this item.)