Martina Flörke (Kassel University)
Freshwater withdrawals have doubled between 1960 and 2010 and increased from 1,968 km³/year to 3,853 km³/year (Shiklomanov & Rodda, 2003; FAO AQUASTAT, 2016). The amount of water used varies between sectors and thus essentially determines the water use profile of a country or region, i.e. indicating the key water users within a certain area or region. In 2010, 12% were withdrawn for domestic purposes (households and small businesses), 19% by the industry sector, and 69% by the agricultural sector, mainly for irrigation requirements. The share of water abstractions per sector differs by countries and regions, for example, 82% of the water withdrawn in Asia is used by agriculture, while only 9% belongs to the industry and domestic sectors. Contrary, in Europe most of the water is used for industrial activities (55%) followed by agriculture (29%) and the domestic sectors (16%). Accordingly, the amount of water withdrawn varies enormously between regions and countries; e.g. regional estimates of total water withdrawals amount to 2,451 km³ or 642 m³ per capita in Asia but only to 374 km³ or 82 m³ per capita in Europe (FAO AQUASTAT, 2010).
Water demand continues to increase globally, as the world population grows and nations become wealthier and consume more. As water demands get closer and closer to the renewable freshwater resource availability, each drop of freshwater becomes increasingly valuable and water must be managed more efficiently and intensively. Planning for future development and investments requires that we prepare water projections for the future. However, estimations are complicated because the future of World’s waters will be influenced by a combination of important environmental, social, economic and political factors, such as global climate change, population growth, land use change, globalization and economic development, technological innovations, political stability and international cooperation.
The global Water Use model of WaterGAP3 (Water – Global Assessment and Prognosis) was designed to estimate current and future water withdrawals and consumption of the domestic, industrial and agricultural sectors (aus der Beek et al., 2010; Flörke et al., 2013). In its current version, the Water Use model consists of five different sub-models covering the domestic, manufacturing, thermal electricity production, irrigation, and livestock sectors.
Aus der Beek, T., Flörke, M., Lapola, D. M., Schaldach, R., Voß, F., Teichert, E. (2010). Modelling historical and current irrigation water demand on the continental scale: Europe. Advances in Geosciences 27, 79–85. DOI: 10.5194/adgeo-27-79-2010.
FAO (Food and Agriculture Organization of the United Nations), 2016. AQUASTAT. Available at: www.fao.org/nr/aquastat (Accessed 11 April 2017)
FAO (Food and Agriculture Organization of the United Nations), 2010. AQUASTAT. Available at: www.fao.org/nr/aquastat (Accessed 15 November 2010)
Flörke, M., Kynast, E., Bärlund, I., Eisner, S., Wimmer, F., Alcamo, J. (2013). Domestic and industrial water uses of the past 60 years as a mirror of socio-economic development: A global simulation study. Global Environmental Change 23 (1), 144–156. DOI: 10.1016/j.gloenvcha.2012.10.018.
Shiklomanov, I. A. and Rodda, J. C. 2003. World Water Resources at the Beginning of the 21st Century. International Hydrology Series, Cambridge University Press, Cambridge, UK.