Water scarcity

About: Water scarcity is a research topic. Over the lifetime, 11579 publications have been published within this topic receiving 228756 citations. The topic is also known as: water shortage.

Critical regions: A model-based estimation of world water resources sensitive to global changes

Abstract: This paper presents a top-down approach for identifying regions whose water resources have higher sensitivity to global change than other regions. The aim of this approach is to provide an overview of regions that may justify special attention from the research and development assistance community, under particular global change scenarios. As a 'top-down' method it is best seen as a type of sensitivity analysis that can complement rather than replace other 'bottom-up' studies of the vulnerability of particular watersheds. An increase in 'water stress' is used as a measure of increasing sensitivity of watersheds to global change, and this stress is computed with the global water model, WaterGAP. Stress increases when either water withdrawals increase or water availability decreases. Since the criteria for determining critical regions is uncertain, they are calculated and compared for four different sets of criteria. To examine the difference in critical regions under different socio-economic and climate scenarios, they were also calculated for four distinctive scenarios. Under the scenario showing the largest increase in water stresses, the estimated area of critical regions (in 2032) ranges from 7.4 to 13.0 percent of total land area, depending on the criteria for identifying critical regions. As expected, the estimate of critical regions is very scenario-dependent, showing smaller areas under scenarios having smaller increases in water stress. However, some regions always appear as critical regions regardless of the scenario. These include parts of central Mexico, the Middle East, large parts of the Indian sub-continent, and stretches of the North African coast.

Urban water security: A review

Abstract: We review the increasing body of research on urban water security. First, we reflect on the four different focusses in water security literature: welfare, equity, sustainability and water-related risks. Second, we make an inventory of the multiple perspectives on urban water security: disciplinary perspectives (e.g. engineering, environmental, public policy, public health), problem-oriented perspectives (e.g. water shortage, flooding, water pollution), goal-oriented perspectives (e.g. better water supply and sanitation, better sewerage and wastewater treatment, safety from flooding, proper urban drainage), integrated-water versus water-integrated perspectives, and policy analytical versus governance perspectives. Third, we take a systems perspective on urban water security, taking the pressure-state-impact-response structure as an analytical framework and link that to the ‘urban water transitions framework’ as proposed by Brown et al (Water. Sci. Technol. 59 2009). A systems approach can be helpful to comprehend the complexity of the urban system, including its relation with its (global) environment, and better understand the dynamics of urban water security. Finally, we reflect on work done in the area of urban water security indices.

Water conflicts and social resource scarcity

Abstract: Countering the widely held opinion that water scarcity entails prime risks of international conflicts over shared water resources, it is argued that the risk of conflicts within countries in fact is larger, and that the risk of international conflict is derived from the necessity to avoid what is defined as second-order conflicts within countries, caused not by water scarcity itself, but by the institutional change required to adapt to water scarcity. To illustrate this, the most pernicious effect of social resource scarcity, a new Social Resource Water Stress/Scarcity Index (SWSI) is developed, built on a combination of traditional hydrological indices and the UNDP Human Development Index as the most readily available proxy for social adaptive capacity. Calculations are made for 159 countries, 1995 and with projections to 2025. The study demonstrates that the index captures the social impacts of water scarcity more accurately than earlier indices.

Water resources transfers through Chinese interprovincial and foreign food trade

Abstract: China’s water resources are under increasing pressure from socioeconomic development, diet shifts, and climate change. Agriculture still concentrates most of the national water withdrawal. Moreover, a spatial mismatch in water and arable land availability—with abundant agricultural land and little water resources in the north—increases water scarcity and results in virtual water transfers from drier to wetter regions through agricultural trade. We use a general equilibrium welfare model and linear programming optimization to model interprovincial food trade in China. We combine these trade flows with province-level estimates of commodities’ virtual water content to build China’s domestic and foreign virtual water trade network. We observe large variations in agricultural water-use efficiency among provinces. In addition, some provinces particularly rely on irrigation vs. rainwater. We analyze the virtual water flow patterns and the corresponding water savings. We find that this interprovincial network is highly connected and the flow distribution is relatively homogeneous. A significant share of water flows is from international imports (20%), which are dominated by soy (93%). We find that China’s domestic food trade is efficient in terms of rainwater but inefficient regarding irrigation, meaning that dry, irrigation-intensive provinces tend to export to wetter, less irrigation-intensive ones. Importantly, when incorporating foreign imports, China’s soy trade switches from an inefficient system to a particularly efficient one for saving water resources (20 km3/y irrigation water savings, 41 km3/y total). Finally, we identify specific provinces (e.g., Inner Mongolia) and products (e.g., corn) that show high potential for irrigation productivity improvements.