Decomposing the Changes in Water Intensity in a Mediterranean Region.

This paper proposes a new method for decomposing temporal changes in water use intensity (i.e. quantity of water consumption divided by GDP) into various explanatory factors. Specifically, the changes are decomposed into three elements that clarify some of the hidden reasons behind changes in water use over time. The first one captures changes in water intensity due to sectoral uses, showing the effects of modifying water intensity in the various production sectors. The second shows the changes in sectoral output intensity, showing how altering the production structure affects water consumption. Finally, the third quantifies the effects of changes in residential water intensity, showing how changing the final water uses affects water intensity. The empirical application corresponds to the Spanish region of Catalonia. The results show a reduction in regional water intensity due to a negative contribution from the production structure and residential uses of water, which were greater than the increase in sectoral water intensity. This decomposition shows that the reduced importance of agricultural production had the greatest influence on the reduction in water intensity in this region. The directions and magnitudes of the components identified in this paper highlight the importance of using precise and detailed methods to study water issues. [ABSTRACT FROM AUTHOR]