Carmen Camacho CNRS, University of Paris 1   CNRS, Centre d'Economie de la Sorbonne 106 Boulevard de l'Hôpital Paris, 75013 France   carmen.camacho@univ-paris1.fr             JEL Areas: E2 : Macroeconomics: Consumption, Saving, Production, Employment, and Investment: General (includes Measurement and Data) Q5 : Environmental Economics: General