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.

Entering an era of water scarcity: the challenges ahead.

Abstract: Fresh water is a renewable resource, but it is also finite. Around the world, there are now numerous signs that human water use exceeds sustainable levels. Groundwater depletion, low or nonexistent river flows, and worsening pollution levels are among the more obvious indicators of water stress. In many areas, extracting more water for human uses jeopardizes the health of vital aquatic ecosystems. Satisfying the increased demands for food, water, and material goods of a growing global population while at the same time protecting the ecological services provided by natural water ecosystems requires new ap- proaches to using and managing fresh water. In this article, I propose a global effort (1) to ensure that freshwater ecosystems receive the quantity, quality, and timing of flows needed for them to perform their ecological functions and (2) to work toward a goal of doubling water productivity. Meeting these challenges will require policies that promote rather than discourage water efficiency, as well as new partnerships that cross disciplinary and professional boundaries.

Rice production in water-scarce environments

Abstract: Rice production in Asia needs to increase to feed a growing population. Though a complete assessment of the level of water scarcity in Asian rice production is still lacking, there are signs that declining quality of water and declining availability of water resources are threatening the sustainability of the irrigated rice-based production system. Drought is one of the main constraints for high yield in rain-fed rice. Exploring ways to produce more rice with less water is essential for food security and sustaining environmental health in Asia. This chapter reviews the International Rice Research Institute (IRRI)’s integrated approach, using genetics, breeding and integrated resource management to increase rice yield and to reduce water demand for rice production. Water-saving irrigation, such as saturated-soil culture and alternate wetting and drying, can drastically cut down the unproductive water outflows and increase water productivity. However, these technologies mostly lead to some yield decline in the current lowland rice varieties. Other new approaches are being researched to increase water productivity without sacrifice in yield. These include the incorporation of the C4 photosynthetic pathway into rice to increase rice yield per unit water transpired, the use of molecular biotechnology to enhance drought-stress tolerance and the development of ‘aerobic rice’, to achieve high and sustainable yields in non-flooded soil. Through the adoption of water-saving irrigation technologies, rice land will shift away from being continuously anaerobic to being partly or even completely aerobic. These shifts will have profound changes in water conservation, soil organic-matter turnover, nutrient dynamics, carbon sequestration, soil productivity, weed ecology and greenhouse-gas emissions. Whereas some of these changes can be perceived as positive, e.g. water conservation and decreased methane emission, some are perceived as negative, e.g. release of nitrous oxide from the soil and decline in soil organic matter. The challenge will be to develop effective integrated natural-resource-management interventions, which allow profitable rice cultivation with increased soil aeration, while maintaining the productivity, environmental services and sustainability of rice-based ecosystems.

World Water Vision: Making Water Everybody's Business

Abstract: Word from the President of the World Water Council * Word from the Chairman of the World Water Commission * Preface * Acknowledgements * Executive Summary * Vision Statement and Key Messages * The Use of Water Today * Water Futures * Our Vision of Water and Life in 2025 * Investing for the Water Future * Appendix * Glossary * Bibliography * Index * World Water Council

Balancing Water for Humans and Nature: The New Approach in Ecohydrology

Abstract: Balancing Water for Humans and Nature, authored by two of the world's leading experts on water management, examines water flows - the 'blood stream' of both nature and society - in terms of the crucial links, balances, conflicts and trade-offs between human and environmental needs. The authors argue that a sustainable future depends fundamentally on our ability to manage these trade-offs and encourage long-term resilience. They advocate an ecohydrological approach to land/water/environmental problems and advance a strong, reasoned argument for viewing precipitation as the gross fresh water resource, ultimately responsible for sustaining all terrestrial and aquatic ecosystem services. This book makes the most coherent and holistic argument to date for a new ecological approach to understanding and managing water resources for the benefit of all. Basing their analysis on per capita needs for an acceptable nutritional diet, the authors analyse predictions of the amounts of water needed for global food production by 2050 and identify potential sources. Drawing on small-scale experiences in Africa and Asia, they also cover the vulnerability of the semi-arid tropics through a simplified model of green and blue water scarcity components.

Macro-scale water scarcity requires micro-scale approaches: aspects of vulnerability in semi-arid development

Abstract: 4 types of water scarcity exist. Aridity and intermittent droughts consist of the natural types while land desiccation and water stress are man-made types. Climatic aridity intermittent droughts land degradation and population growth link to create growing critical water scarcity conditions. Specifically in arid lands where only a limited growing season exists anyhow increased and nonsustaining activities spurred on by population growth degrade soils resulting in interference with water recharge of the root zone. This combination precipitates intermittent droughts upsetting the water supply for plants and people. This occurs now in Africa to the degree that by 2025 66% of people will experience severe water shortages. Policymakers in developing countries and bilateral and multilateral development agencies providing technical assistance need to understand these relationships. They must develop a new strategy which includes water resource assessments followed by upgraded water plans for optimal use of available water resources and by the creation of best land use criteria. Their challenge is to balance the acute needs of people with conserving the productivity of the resource base. Experience shows that maximizing agricultural production per unit of water instead of per unit of land can increase income and employment. For example in India a semiarid area produced with a given amount of water as much as 30 times the amount of crops if the crops had a low water demand (e.g. grapes and potatoes) rather than those with a high water demand (e.g. sugarcane). This microscale approach and other such approaches could help semiarid Africa. Yet decision makers must seriously consider the transferability of these approaches to the African cultural and geographical environment. More essential than that however is the very high levels of water stress caused by the rapid population growth in famine-prone African countries.