The Worst-Case Scenario and Discounting the Very Long Term

We propose an ethical viewpoint based on the possibility of the realization of the worst-case scenario in order to reduce future generations risks in terms of discounting. Applied to the question of conservation of a renewable resource, we show that an economy, where the social planner takes into account the possibility that at an uncertain date the discount rate could change to its minimum possible value, could lead to a better conservation of the resource and modify the position of the sacrificed generations. Finally, our model suggests to apply the lowest possible discount rate immediately for long term environmental projects.Discounting ; environment ; uncertainty ; preservation of natural resources ; intergenerational equity.

The Worst-Case Scenario and Discounting the Very Long Term

URL des Cahiers : https://halshs.archives-ouvertes.fr/CAHIERS-MSECahiers de la Maison des Sciences Economiques 2006.05 - ISSN 1624-0340We propose an ethical viewpoint based on the possibility of the realization of the worst-case scenario in order to reduce future generations risks in terms of discounting. Applied to the question of conservation of a renewable resource, we show that an economy, where the social planner takes into account the possibility that at an uncertain date the discount rate could change to its minimum possible value, could lead to a better conservation of the resource and modify the position of the sacrificed generations. Finally, our model suggests to apply the lowest possible discount rate immediately for long term environmental projects.Nous proposons une approche basée sur la possibilité de la réalisation du pire scénario pour réduire les risques encourus par les générations futures en termes de taux d'actualisation dès maintenant. Appliquée à la question de la préservation d'une ressource renouvelable, nous montrons qu'une économie dans laquelle le planificateur social prend en compte la possibilité d'un changement du taux d'actualisation à sa valeur minimale à une date future incertaine peut conduire à une meilleure préservation de la ressource et modifier la position des générations sacrifiées. Finalement, notre modèle suggère d'appliquer le taux le plus faible possible dès aujourd'hui pour des projets environnementaux de long terme

Potential damage costs of Diabrotica virgifera virgifera infestation in Europe – the “no control” Scenario

The Western Corn Rootworm (WCR or Dvv., Diabrotica virgifera virgifera Le Conte) was first detected in Europe in the early nineties in Serbia. Since then the beetle spread to more than 15 European countries. We assess the potential damage costs of the invasive species Diabrotica virgifera virgifera LeConte (Dvv.) in Europe under a “no control” scenario. While previous studies considered benefits and costs at country level this study explicitly investigates the external benefits of control in one country for other countries. The assessment considers the spatial and temporal aspects of invasion considering a number of scenarios developed together with experts. The results indicate enormous economic benefits can be gained by controlling further spread of Dvv. They economic benefits of control range between 143 million Euro in the best case and 1739 million Euro in the worst case scenario. The most likely scenario results in average annual economic benefits of 472 million Euro. Even in countries that not face high damage costs control can be justified as this will reduce the speed of spread of the WCR and generates a positive externality for other regions with higher damage costs.damage control, invasive species, spatial model

Dynamique des ressources renouvelables et actualisation endogène

URL des Cahiers : https://halshs.archives-ouvertes.fr/CAHIERS-MSECahiers de la Maison des Sciences Economiques 2005.84 - ISSN : 1624-0340This paper develops a simple model of optimal growth with renewable resource and endogenous discounting. Relaxing the time-additivity preference hypothesis allows to make endogenous the rate of time preference and to reconsider the dynamics of models with concave resource. The possibility of multiples equilibria with thresholds is examinated in this setup. It is also underlined the importance of initial conditions, particularly in terms of environmental resource, on the long run dynamic of economies.Cet article développe un modèle de croissance optimale avec ressource renouvelable et actualisation endogène. Le relâchement de l'hypothèse de préférence additivement séparable permet de rendre endogène le taux de préférence pour le présent et de reconsidérer la dynamique des modèles avec ressource concave. La possibilité d'équilibres multiples avec seuil est examinée dans ce cadre. Il est ainsi souligné l'importance des conditions initiales, notamment en termes de ressource environnementale, dans la dynamique de long terme des économies

Dynamique des ressources renouvelables et actualisation endogène

Cet article développe un modèle de croissance optimale avec ressource renouvelable et actualisation endogène. Le relâchement de l'hypothèse de préférence additivement séparable permet de rendre endogène le taux de préférence pour le présent et de reconsidérer la dynamique des modèles avec ressource concave. La possibilité d'équilibres multiples avec seuil est examinée dans ce cadre. Il est ainsi souligné l'importance des conditions initiales, notamment en termes de ressource environnementale, dans la dynamique de long terme des économies.Ressource renouvelable, croissance, escompte endogène, équilibres multiples.

Bilan et défis des reformes harmonisées de programmation budgétaire en Afrique : cas du CDMT, Quid de l’expérience du Sénégal ?

Several reforms marked the fiscal management in Africa in the past decades. The Public Financial Management Systems in many African countries are greatly affected by problems regarding the budget preparation process, its execution and its control. The Medium Term expenditure Framework (MTEF) has emerged in this context of research of performance improvement. In the countries of the West African Economic and Monetary Union (WAEMU), the implementation of the 2009 directives pertaining to the harmonized framework for the public finances is a major focus of political integration through the application of the convergence criteria via the generalization of best practices in budget management. The rapid spread of the MTEFs as a tool for multi-year budgeting raises many questions about their impacts. This article revisits the recent and uneven development of the MTEFs in Africa and initiates an initial assessment of MTEF as applied in Senegal, in the light of its generic goals and by using the non-parametric statistics. Like the few existing evaluations on MTEF in Africa, this study analyzes the effectiveness of the MTEF in the process of budget allocation to priority sectors of development. The results show that the MTEF has not allowed a tangible improvement in fiscal discipline and has not lead to a redeployment towards these sectors. However, an acceptable budget programming is noted in the case of Senegal with realistic the multi-year projections. Ultimately, the study shows that the MTEF approach has significant potential remains unexploited as reforms remain incomplete in Africa