رشد اقتصادی و تحول مصرف آب در اسپانیا: یک تحلیل تخریب ساختاری

The aim of this paper is to examine how technology, processes of input substitution, and changes in final demand, all of which underlie economic growth, influence water consumption. This analysis is undertaken for Spain during a significant socio-economic period, from 1980, the beginning of the democratic era, to 2007, the onset of the current economic crisis. To this end, we construct water consumption series linked to a time series of input–output tables generated for the Spanish economy, and we develop a structural decomposition analysis to study mainly changes in water consumption embodied in final demand. We find that the growth in Spanish demand (all other things being constant) would have implied an increase in water consumption almost three times the growth actually observed. However, this demand effect is largely offset by technology and intensity effects, mainly due to changes in agricultural crops. Given the importance of the demand growth, the final demand effect is also analyzed in detail, broken down by categories as well as level and composition. Household demand and the increase of exports appear as key explicative factors.

Economic growth is influenced by changes in technologies, processes of input substitution, and changes in final demands. These technological, structural and demand factors also influence the patterns of resource consumption. The aim of this paper is to examine the impact of these factors on the evolution of water consumption. This analysis is undertaken for a Mediterranean country, Spain,3 and for a period of time, 1980 to 2007, in which the current configuration of the Spanish economic structure has become settled. During these three decades, the Spanish economy experienced an economic, productive, and social transformation without precedent. From the beginning of the democratic period, in the late 1970s, until the recent and severe economic crisis in 2008, Spain was regarded as one of the most dynamic EU countries. Sustained growth rates that were higher than the European average during the 1990s (particularly since the economic crisis of 19924). They allowed the Spanish economy to reduce, in part, the significant gap in per capita income that had long differentiated it from the rest of Europe. Integration into the European Union, in 1985, launched a process of economic openness that enabled a higher level of trade. It also allowed for the progressive adoption of technologies and production methods then common in neighboring advanced countries. This process transformed markets and productive activity, increased the per capita income of Spain, and expanded and changed patterns of consumption. The 1990s attracted significant amounts of foreign investment, and low interest rates facilitated a boom in the real-estate sector, with construction – during the first decade of the 2000s – accounting for more than 15% of GDP and employment growth. Moreover, during this same period, funding from the EU contributed significantly to the economic empowerment of Spain. Agricultural funds from the Common Agricultural Policy of the EU, along with structural and cohesion funds, drastically transformed the rural and urban landscape. This contributed to a rapid and widespread access to irrigation and cultivation technologies, a significant improvement in transport and energy networks, a broad access to the knowledge society (R&D, innovation, information), and notable agricultural and rural development. These profound economic and social transformations have also modified the patterns of consumption and use of resources, particularly of water. Changes in the size and composition of final demand, a greater share for the industrial and service sectors, structural and technological changes, and a significant transformation in agriculture (with a major focus on industrial and high-value-added products, and adoption of new irrigation technologies) drove – or coexisted with – an increase of about 30% in the direct consumption of (essentially green) water, from 1980 to 2007, according to our estimations presented here. The study of water use and its evolution is particularly important in Spain, where a combination of spatial and time irregularity of precipitation, together with an inefficient hydrological planning regime, has caused permanent imbalances between resources and requirements. This situation has been made worse over time by a model of economic growth based on a major extension of water-intensive crops in the agricultural sector, weak water-saving tendencies in industrial activity, and urban and tourism development (in many cases uncontrolled) that was highly intensive in the use of water. In this general context, our objective is to analyze the role played by demand, and by the structural and technological changes underlying Spain's economic growth. More specifically, we want to go further in the study of the determinants of economic growth (mainly demand growth, structural change, and technological change). Offering insights into how much the pressure on natural resources, specifically water, has changed during almost thirty years. Sectoral and temporal perspectives are important in understanding the nature of this evolution. In our view, the relevance of the analysis goes beyond the specific case studied, showing how economic dynamics have an environmental impact, and how these interrelated dynamics and impacts can be studied and interpreted. The analysis might be especially interesting for other arid or semi-arid regions, where water is scarce and there are severe rainfall and climatic irregularities. Input–output models are suitable tools to examine the direct and indirect requirements of inputs, and the impact of economic growth on natural resources. More concretely, the extension of the traditional Leontief's input–output economic model to environmental indicators, explained by Leontief and Ford (1972) and Miller and Blair (1985), opened the field to much greater use of extended input–output models. In the case of water, works in line with the early contributions of Lofting and McGauhey (1968) and Carter and Irei (1970) can be found, with new applications of the input–output methodology to assess the water uses of different economies, e.g. Lenzen and Foran (2001), and Guan and Hubacek, 2007 and Guan and Hubacek, 2008 among others. For Spain, studies such as Duarte et al. (2002), Sánchez-Chóliz and Duarte (2003) and Velázquez (2006) use the input–output model to estimate the water embodied in economic production at the national or regional levels, while Dietzenbacher and Velázquez (2007) focus on the virtual water trade in a regional context. More recently, Cazcarro et al. (2012) calculate the water flows embodied in Spanish international trade, and simulate the water impacts associated with different scenarios of household consumption in Spain. From the temporal perspective, Structural Decomposition Analysis (SDA) will be applied in our study to analyze the evolution of direct and indirect water consumption. SDA has been widely used to study the evolution of economic variables and the role played by demand, technology, and intensity in environmental analysis (see Rose and Casler, 1996 and Hoekstra and Van der Berg, 2002, for a review of these issues; and Wood and Lenzen, 2009, on the methodological approaches to the study of sustainable consumption). Through our interest in linking the pressure on water resources to the structural and technological changes that occurred in Spain, we apply an SDA to a set of Spanish input–output tables estimated for the period 1980–2007, and we obtain different components that explain the evolution of water consumption. To the best of our knowledge, this is the first attempt to analyze the evolution of water consumption over time, looking at the contribution of different sectors and growth components to this evolution. The rest of the paper is structured as follows: Section 2 presents the methodological aspects of the SDA applied; Section 3 is devoted to the construction of the database; Section 4 presents our results, and Section 5 reviews our main conclusions.

The objective of this paper has been to provide some insights into the evolution of water consumption in the Spanish economy during an interesting period, 1980 to 2007. Our results reveal that water consumption during these years grew by 18,047 hm3, a large enough figure in itself, but one that acquires its true dimensions when compared to the Spanish population. The population of Spain in 2007 was 44.873 million and the figure represents an increase in consumption of around 402 hm3 per million people, or 14,888 l per person in each of the 27 years studied. This synthetic number shows that the Spanish economy has evolved towards a more water-intensive society, without compelling evidence of changes in this trend. Demand growth has been the main factor driving the increase in water consumption growth, and household demand and increased exports are key factors in this. Changes in consumption patterns, a significant growth of per capita income, better opportunities for Spanish products abroad, tourism development, construction and infrastructure development have all played their part. Improvements in production technologies and not only in agriculture, have contributed in the opposite direction, pushing reductions in water consumption, especially in agricultural and livestock goods sold to the final consumer and other sectors (e.g. hotels and restaurants). Without reductions through crop-intensity and other changes in the production structure, water consumption could have increased more than four times the real increase. Imports have also pushed reductions, saving water through the inputs — substitution process, thus avoiding an even greater pressure on domestic water resources. As for the limitations of our analysis, we believe that they serve to point to a natural extension of our work. First, throughout our study, we have side-stepped certain important issues in Spain, such as the role of rain-fed agriculture and irrigation, the modernization of irrigation systems and the recycling of water from agricultural and industrial uses. Although some of these issues lie behind the changes we have discussed, they have not been considered directly in our model. Second, foreign trade and the domestic consumption of agricultural and food products are key to understanding the evolution of the agrarian sector and its consequences for water demand. Consequently, a more detailed analysis of water embodied in current international flows, and a more in-depth study of household consumption by different economic and social groups may help in identifying future trends in water consumption. Finally, Spain is immersed in an economic crisis without precedent that, without doubt, will lead to a different production and consumption schema. To design scenarios of economic and sustainable growth, in which water resources and other pressures on the environment are taken into account, is not only a scientific challenge, but also a responsibility to society.