Katheline Schubert (Paris School of Economics) Titre : Preference Shifts and the Green Transition in General Equilibrium Résumé :  This paper studies demand side climate transitions in a taste-heterogeneous brown--green economy. We compare two shocks that can be calibrated to generate the same fall in brown consumption in partial equilibrium: a green-preference shock, interpreted as sufficiency, and a carbon tax. We show that the two shocks are not equivalent in general equilibrium. A carbon tax creates a wedge between the consumer and producer prices of the brown good, while a preference shock shifts demand directly and operates through the endogenous brown producer price. Sufficiency is therefore not a voluntary carbon tax. With heterogeneous households, the distributional incidence of both shocks is governed by the mismatch between exposure to brown consumption and exposure to brown labor income. A fall in the brown producer price benefits net brown consumers and hurts net brown workers. Sufficiency is therefore not distributionally neutral: even when preference changes are voluntary for the agents who undertake them, they affect others through equilibrium prices. A carbon tax has a different incidence structure because it combines this producer price channel with a direct consumer price wedge and a fiscal recycling channel. We characterize rebound, real income effects, and fixed-preference welfare effects. Preference shocks can generate substantial rebound because the induced fall in the brown producer price makes brown goods cheaper. The strength of this rebound depends on goods substitutability, labor reallocation, and the joint distribution of brown consumption and brown labor income exposures. We also show that real income and welfare must be distinguished when preferences change: measured real income includes a preference-index revaluation term, whereas fixed-preference welfare isolates the material effects operating through prices and incomes. Numerical illustrations for France and for the international economy show that equalizing partial equilibrium brown consumption reductions does not equalize general equilibrium reductions, and highlight which group of households/countries are the winners and the losers of a demand side driven transition. A joint work with Youssef Salib. Download slides