Jeudi 12 Mai à 10h30
Matthieu Glachant (CERNA) : "Invention and Transfer of Climate Change Mitigation Technologies on a Global Scale : A Study Drawing on Patent Data"
Jeudi 7 Mai, 10 h 30
Patrice Dumas, Stephane Hallegatte (CIRED) :
Think again : a higher elasticity of substitution increases economic
resilience to price shocks.
This paper shows that, counter-intuitively, a higher elasticity of substitution in model production function with an unchanged initial state can lead to reduced resilience and larger vulnerability to shocks in production factor prices. This result is due to the fact that assuming a higher elasticity of substitution requires a recalibration of the production function parameters to keep the model initial state unchanged. This result has consequences for economic analysis, e.g., on the economic vulnerability to oil shocks.
Climate Change Economic Damages : Influence of Inertia Heterogeneity and Ripple Effects in a Two-Sector Model
This paper shows that assessing the economic costs of climate change requires to take into account (i) the specificities of infrastructures, namely a large exposure to climate and a long lifetime that makes it difficult to adapt them to a climate which is changing and uncertain, and (ii) the large reliance of the whole economy on key infrastructures. To do so, this paper proposes a two-sector model in which the first sector represents the production of infrastructure and housing services, and analyses its response to climate change. Then, it proposes a methodology to remove ripple effects in economic models and uses it to assess which fraction of the economic cost of climate change would arise from indirect impacts. Finally, the paper emphasizes (i) that changes in the investment structure can very efficiently reduce the impacts of cross-sectoral ripple effects ; (ii) that, surprisingly, damages are lower when considering infrastructure and housing inertia explicitly, provided optimal changes in the investment structure. Considering the fact that infrastructure and housing are strongly regulated sectors, and most of time heavily supported by governments, these results stress the need for and the efficiency of an adequate public response to reduce climate change impacts.
Jeudi 23 avril 10h30
Séminaire à plusieurs voix sur le paquet climat énergie européen, animé par Sandrine Mathy, Alain Nadaï et Philippe Quirion.
Lundi 23 mars, 10 h 30
“The geography of sustainability : Agglomeration, global economy and environment” Fabio GRAZI , Henri WAISMAN and Jeroen C.J.M. van den BERGH
Abstract :
In spite of repeated and widely supported claims for international action to enhance sustainable development, the actual implementation of it has been slow and far from complete. An important reason is the difficulty to translate the general and arguably vague notion of sustainable development into concrete principles and actions at local, regional and national levels, where governance is most concrete and effective (OECD, 2007). This is partly due to analyses of sustainable development lacking systematic attention for spatial dimensions, such as land use, transport, regional and urban development, international trade and various spatial and trade policies. In this study, we make use of the concept of ‘spatial sustainability’, reflecting a spatial configuration and spatial dynamics of local production and consumption activities that is consistent with environmental sustainability. An adequate treatment of spatial sustainability involves a combination of dynamic, spatial and economic model components, which can be operationalized through the adoption of a system of regions and trade relations. The lack of such a framework has already been recognized in the literature on sustainable development, and some conceptual starting points are available (van den Bergh and Verbruggen, 1999 ; Verhoef and Nijkamp, 2002). This paper presents a theoretical two-region framework and analyzes the impact of the spatial configuration of economic activities (agriculture and industry), employees and consumers on the (un)sustainability of the economy in the long run. The model presented is an extension of Grazi et al. (2007), who focused on a (relatively) short-run equilibrium of the spatial economy. Their model extended the well-known Core-Periphery model by Krugman (1991), which describes agglomeration and trade in a two-region system, with regional and transboundary (global) environmental degradation and with various types of land uses. This model assumes a given homogenous population distribution across regions for each spatial configuration. Regions are thus identical in terms of the endowment of the two primary input factors, namely human capital and unskilled labor. By following Forslid and Ottaviano’s (2003) assumption on labor skill heterogeneity, the model was solved analytically and subsequently used to derive a performance ranking of spatial configurations on the basis of social welfare and an influential (though debated) environmental indicator, namely the ecological footprint. We extend the model by Grazi et al. (2007) with dynamic features, which will allow us to generate information about long-term aspects of sustainable development. This requires attention for dynamic aspects of land use, environmental damage, location decisions, and trade. These aspects enter the model through dynamics mechanisms that account for factor mobility, long-run trade patterns, and constraints on future pollution flows and stock. As a result, the economy can include an uneven spatial distribution of the population and safe levels of pollution in the long term. The model allows us to examine spatial sustainability of the economy in a thorough manner. Spatial sustainability depends on both the form (agglomeration or spread-out pattern) and the regional concentration (size) of the population and economy, as these will affect the level of negative, environmental externalities. Three spatial configurations are considered : configuration A (B) in which both regions are spread-out (agglomerated), and configuration C in which one region is agglomerated and the other is spread-out. The model is numerically analyzed to examine long-run spatial-economic equilibria under different settings for the three determinants of spatial sustainability. First, the sustainability characteristics of the long-run equilibrium are studied by varying the pollution assimilation capacity and the trade parameter, which is a core driver of spatial structure. In addition, a ranking of sustainable spatial configurations is derived according to their performance in terms of global welfare. For a sufficiently low assimilation capacity, only spatial configuration A (no agglomeration, i.e. a spread-out spatial structure in both regions) can satisfy the sustainability condition and thus performs best in terms of sustainable welfare. For slightly higher values of the assimilation capacity, both configurations A and C meet the sustainability requirement in the long run. Spatial configuration C (one region agglomerated) is sustainable as long as trade costs are high enough and performs better on spatial welfare than configuration A. Sufficiently high values of trade cost mean a soft constraint on the economy in terms of barriers on the intensity of trade activity, and thus a small impact on global welfare. For an even higher assimilation capacity and sufficiently high trade costs, all three spatial configurations can satisfy the sustainability condition, while configuration B (two regions agglomerated) reaches the highest level of welfare. Finally, for the highest values assimilation capacity and trade costs all three spatial configurations include sustainable long-run equilibria, while configuration C scores best in terms of welfare. Next, we studied whether results altered much if parameters capturing the intensity of the impact of environmental and agglomeration externalities change. In particular, we tested how the welfare ranking of the alternative spatial configurations responds to changes in the values of these parameters. Our approach and results provide a novel contribution to the current debate on sustainable development of spatial economies, by giving attention to local or regional and urban (agglomeration) aspects. This is relevant to sustainability policy, including those strategies associated with climate change. Here the international global perspective and technical solutions so far has been unable to provide a satisfactory solution. Spatial re-organization of economic activities needs attention here as well, and the current framework can help to study relevant questions. By means of a general equilibrium modeling framework in the spirit of the new economic geography, the current study has aimed at widening the spectrum of possible effective approaches to study sustainability. In particular, our approach provides a specific and policy-relevant tool to examine the notion of spatial sustainability.
REFERENCES Bergh J.C.J.M. van den, and H. Verbruggen. 1999. ‘Spatial Sustainability, Trade and Indicators : An Evaluation of the Ecological Footprint.’ Ecological Economics 29, 61-72. Forslid, R., and G.I.P. Ottaviano. 2003. ‘An Analytically Solvable Core-Periphery Model.’ Journal of Economic Geography 3, 229-240. Grazi, F., J.C.J.M. van den Bergh, and P. Rietveld. 2007. ‘Spatial Welfare Economics versus Ecological Footprint : Modeling Agglomeration, Externalities, and Trade.’ Environmental and Resource Economics 38, 135-153. Krugman. P. 1991. ‘Increasing Returns and Economic Geography.’ Journal of Political Economy 99, 483-499 OECD. 2007. 2007-2008 Programme of Work of the OECD Territorial Development Policy Committee. Organization for Economic Co-operation and Development, OECD, Paris. Verhoef, E.T., and P. Nijkamp. 2002. ‘Externalities in Urban Sustainability : Environmental versus Localization-Type Agglomeration Externalities in a General Spatial Equilibrium Model of a Single-Sector Monocentric Industrial City.’ Ecological Economics 40, 157-179.
Jeudi 12 mars à 10h30
Michel de Lara (Cermic) : "Décision séquentielle, contraintes, incertitudes : méthodes de viabilité en temps discret pour la gestion durable des ressources naturelles"
Michel de Lara Présentera les concepts et méthodes de contrôle de systèmes dynamiques en temps discret, en insistant sur la prise en compte des contraintes (viabilité). Il illustrera ceci en parallèle sur plusieurs exemples de gestion de ressources naturelles. Il abordera le cas de la décision séquentielle sous contraintes et incertitudes (viabilité stochastique), qui peut être intéressante pour formaliser la gestion du dossier climatique.
Jeudi 8 janvier à 10h30
Guy Meunier (Gis Larsen) : Capacity decisions with demand fluctuations and carbon leakage.
Jeudi 30 octobre
Jean Cavailhès et Daniel Joly (INRA) : "the price of climate : revealed preferences of French consumers".
This paper investigates the optimal mix between home capacity and imports to face an uncertain demand. It is proved that, if the difference between the home variable cost and the import price is large, the optimal home capacity increases as uncertainty increases, while it decreases if it is small. The model is calibrated using data from the cement sector to study the impact of a unilateral high CO2 price in Europe. The results suggest a higher carbon leakage rate and more relocation of the industry than deterministic models would.
Jeudi 16 octobre 2008
Thierry Brunelle (CIRED) présentera le travail en cours sur Nexus Land-Use, le modèle d’allocation des terres en cours d’intégration à Imaclim.
Nicolas Vuichard (LSCE) : Opportunité environnementale sur les terres agricoles d’ex-URSS à l’abandon : produire des agrocarburants ou stocker du carbone dans les sols ?
Les énergies fossiles responsables de rejets atmosphériques de CO2 à l’origine du changement climatique, voient leurs ressources diminuer. Dans ce contexte, les agrocarburants, dont l’énergie provient des produits de la photosynthèse des plantes, ont un rôle potentiel à jouer dans l’objectif mondial de développer de nouvelles voies énergétiques non émettrices de CO2 qui se substitueraient aux énergies fossiles. Cependant, de nombreuses études ont récemment montré que la production à grande échelle d’agrocarburants pouvaient s’accompagner d’impacts négatifs tant sur l’environnement (Fargione et al. 2008 ; Crutzen et al. 2007) que sur la sécurité alimentaire (Johansson et al. 2007 ; Naylor et al. 2007). Aussi, les terres agricoles à l’abandon apparaissent-elles comme les surfaces les plus adéquates pour produire des agrocarburants qui reduiraient les émissions de CO2, sans rentrer en compétition avec la production alimentaire (Field et al. 2007 ; Campbell et al. 2008). Il présentera un travail de modélisation qui a permis de quantifier le bénéfice environnemental (réduction des émissions de CO2) associé à la production d’agrocarburants sur les terres agricoles d’ex-URSS à l’abandon. Il confrontera ce bénéfice environnemental au stockage de carbone induit par la recolonisation d’espèces naturelles suite à l’abandon de ces terres agricoles. Enfin, il discutera de la sensibilité de ces résultats au "timing" de mise en production des agrocarburants.
