Quand « l’irrigation verte » augmente la demande d’eau

Improving the efficiency of water use is usually presented as an opportunity for water conservation in the agricultural sector. Using more efficient irrigation systems should lead to similar levels of agricultural yields, by using a smaller volume of water (green irrigation). However, a more efficient irrigation system can paradoxically encourage agricultural producers to use more water. This effect, known as the rebound effect, is linked to the increase in the productivity of the production factor. The aim of this article is to identify the factors that ensure the efficiency of green irrigation. Our contribution is to develop a model that takes into account the evolution of energy costs. Our results suggest that more efficient irrigation technologies result in an increase in water demand (rebound effect) and in energy demand. The rebound effect is partially offset by an increase in energy costs, but energy consumption can contribute to the emission of greenhouse gases. Decision makers must therefore coordinate the objectives of environmental policies in water and energy, so that they can be achieved and not neutralized.