Water scarcity involves water stress, water shortage or deficits, and water crisis. The concept of water stress is relatively new. Water stress is the difficulty of obtaining sources of fresh water for use, because of depleting resources. A water crisis is a situation where the available potable, unpolluted water within a region is less than that region's demand.
Some have presented maps showing the physical existence of water in nature to show nations with lower or higher volumes of water available for use. Others have related water availability to population. A popular approach has been to rank countries according to the amount of annual water resources available per person. For example, according to the Falkenmark Water Stress Indicator, a country or region is said to experience "water stress" when annual water supplies drop below 1,700 cubic metres per person per year. At levels between 1,700 and 1,000 cubic metres per person per year, periodic or limited water shortages can be expected. When water supplies drop below 1,000 cubic metres per person per year, the country faces "water scarcity". The United Nations' FAO states that by 2025, 1.9 billion people will be living in countries or regions with absolute water scarcity, and two-thirds of the world population could be under stress conditions. The World Bank adds that climate change could profoundly alter future patterns of both water availability and use,thereby increasing levels of water stress and insecurity, both at the global scale and in sectors that depend on water.
Another measurement, calculated as part of a wider assessment of water management in 2007, aimed to relate water availability to how the resource was actually used. It therefore divided water scarcity into ‘physical’ and ‘economic’. Physical water scarcity is where there is not enough water to meet all demands, including that needed for ecosystems to function effectively. Arid regions frequently suffer from physical water scarcity. It also occurs where water seems abundant but where resources are over-committed, such as when there is overdevelopment of hydraulic infrastructure for irrigation. Symptoms of physical water scarcity include environmental degradation and declining groundwater. Water stress harms living things because every organism needs water to live.
Economic scarcity 
Economic water scarcity, meanwhile, is caused by a lack of investment in water or insufficient human capacity to satisfy the demand for water. Symptoms of economic water scarcity include a lack of infrastructure, with people often having to fetch water from rivers for domestic and agricultural uses. Large parts of Africa suffer from economic water scarcity; developing water infrastructure in those areas could therefore help to reduce poverty. Critical conditions often arise for economically poor and politically weak communities living in already dry environment.
Water stress 
Fifty years ago, when there were fewer than half the current number of people on the planet, the common perception was that water was an infinite resource. People were not as wealthy then as they are today, consumed fewer calories and ate less meat, so less water was needed to produce their food. They required a third of the volume of water we presently take from rivers. Today, the competition for water resources is much more intense. This is because there are now over seven billion people on the planet, their consumption of water-thirsty meat and vegetables is rising, and there is increasing competition for water from industry, urbanization and biofuel crops.
The total amount of available freshwater supply is also decreasing because of climate change, which has caused receding glaciers, reduced stream and river flow, and shrinking lakes. Many aquifers have been over-pumped and are not recharging quickly. Although the total fresh water supply is not used up, much has become polluted, salted, unsuitable or otherwise unavailable for drinking, industry and agriculture. To avoid a global water crisis, farmers will have to strive to increase productivity to meet growing demands for food, while industry and cities find ways to use water more efficiently.
The New York Times article, "Southeast Drought Study Ties Water Shortage to Population, Not Global Warming", summarizes the findings of Columbia University researcher on the subject of the droughts in the American Southeast between 2005 and 2007. The findings were published in the Journal of Climate. They say the water shortages resulted from population size more than rainfall. Census figures show that Georgia’s population rose from 6.48 to 9.54 million between 1990 and 2007. After studying data from weather instruments, computer models and measurements of tree rings which reflect rainfall, they found that the droughts were not unprecedented and result from normal climate patterns and random weather events. "Similar droughts unfolded over the last thousand years", the researchers wrote, "Regardless of climate change, they added, similar weather patterns can be expected regularly in the future, with similar results." As the temperature increases, rainfall in the Southeast will increase but because of evaporation the area may get even drier. The researchers concluded with a statement saying that any rainfall comes from complicated internal processes in the atmosphere and are very hard to predict because of the large amount of variables.
Water crisis 
When then there is not enough potable water for given necessity, the threat of a water crisis is realized. The United Nations and other world organizations consider a variety of regions to have water crises such that it is a global concern. Other organizations, such as the Food and Agriculture Organization, argue that there is no water crises in such places, but that steps must still be taken to avoid one.
There are several principal manifestations of the water crisis.
- Inadequate access to safe drinking water for about 884 million people
- Inadequate access to water for sanitation and waste disposal for 2.5 billion people
- Groundwater overdrafting (excessive use) leading to diminished agricultural yields
- Overuse and pollution of water resources harming biodiversity
- Regional conflicts over scarce water resources sometimes resulting in warfare
Waterborne diseases and the absence of sanitary domestic water are one of the leading causes of death worldwide. For children under age five, waterborne diseases are the leading cause of death. At any given time, half of the world's hospital beds are occupied by patients suffering from waterborne diseases. According to the World Bank, 88 percent of all waterborne diseases are caused by unsafe drinking water, inadequate sanitation and poor hygiene.
Water is the underlying tenuous balance of safe water supply, but controllable factors such as the management and distribution of the water supply itself contribute to further scarcity.
A 2006 United Nations report focuses on issues of governance as the core of the water crisis, saying "There is enough water for everyone" and "Water insufficiency is often due to mismanagement, corruption, lack of appropriate institutions, bureaucratic inertia and a shortage of investment in both human capacity and physical infrastructure". Official data also shows a clear correlation between access to safe water and GDP per capita.
It has also been claimed, primarily by economists, that the water situation has occurred because of a lack of property rights, government regulations and subsidies in the water sector, causing prices to be too low and consumption too high.
Vegetation and wildlife are fundamentally dependent upon adequate freshwater resources. Marshes, bogs and riparian zones are more obviously dependent upon sustainable water supply, but forests and other upland ecosystems are equally at risk of significant productivity changes as water availability is diminished. In the case of wetlands, considerable area has been simply taken from wildlife use to feed and house the expanding human population. But other areas have suffered reduced productivity from gradual diminishing of freshwater inflow, as upstream sources are diverted for human use. In seven states of the U.S. over 80 percent of all historic wetlands were filled by the 1980s, when Congress acted to create a “no net loss” of wetlands.
In Europe extensive loss of wetlands has also occurred with resulting loss of biodiversity. For example many bogs in Scotland have been developed or diminished through human population expansion. One example is the Portlethen Moss in Aberdeenshire.
On Madagascar’s highland plateau, a massive transformation occurred that eliminated virtually all the heavily forested vegetation in the period 1970 to 2000. The slash and burn agriculture eliminated about ten percent of the total country’s native biomass and converted it to a barren wasteland. These effects were from overpopulation and the necessity to feed poor indigenous peoples, but the adverse effects included widespread gully erosion that in turn produced heavily silted rivers that “run red” decades after the deforestation. This eliminated a large amount of usable fresh water and also destroyed much of the riverine ecosystems of several large west-flowing rivers. Several fish species have been driven to the edge of extinction and some, such as the disturbed Tokios coral reef formations in the Indian Ocean, are effectively lost.
In October 2008, Peter Brabeck-Letmathe, chairman and former chief executive of Nestlé, warned that the production of biofuels will further deplete the world's water supply.
Overview of regions suffering crisis impacts 
There are many other countries of the world that are severely impacted with regard to human health and inadequate drinking water. The following is a partial list of some of the countries with significant populations (numerical population of affected population listed) whose only consumption is of contaminated water:
According to the California Department of Resources, if more supplies aren’t found by 2020, the region will face a shortfall nearly as great as the amount consumed today. Los Angeles is a coastal desert able to support at most 1 million people on its own water; the Los Angeles basin now is the core of a megacity that spans 220 miles (350 km) from Santa Barbara to the Mexican border. The region’s population is expected to reach 41 million by 2020, up from 28 million in 2009. The population of California continues to grow by more than two million a year and is expected to reach 75 million in 2030, up from 49 million in 2009. But water shortage is likely to surface well before then.
Water deficits, which are already spurring heavy grain imports in numerous smaller countries, may soon do the same in larger countries, such as China and India. The water tables are falling in scores of countries (including Northern China, the US, and India) due to widespread overpumping using powerful diesel and electric pumps. Other countries affected include Pakistan, Iran, and Mexico. This will eventually lead to water scarcity and cutbacks in grain harvest. Even with the overpumping of its aquifers, China is developing a grain deficit. When this happens, it will almost certainly drive grain prices upward. Most of the 3 billion people projected to be added worldwide by mid-century will be born in countries already experiencing water shortages. Unless population growth can be slowed quickly it is feared that there may not be a practical non-violent or humane solution to the emerging world water shortage.
After China and India, there is a second tier of smaller countries with large water deficits — Algeria, Egypt, Iran, Mexico, and Pakistan. Four of these already import a large share of their grain. But with a population expanding by 4 million a year, it will also likely soon turn to the world market for grain.
According to a UN climate report, the Himalayan glaciers that are the sources of Asia's biggest rivers - Ganges, Indus, Brahmaputra, Yangtze, Mekong, Salween and Yellow - could disappear by 2035 as temperatures rise. It was later revealed that the source used by the UN climate report actually stated 2350, not 2035. Approximately 2.4 billion people live in the drainage basin of the Himalayan rivers. India, China, Pakistan, Bangladesh, Nepal and Myanmar could experience floods followed by droughts in coming decades. In India alone, the Ganges provides water for drinking and farming for more than 500 million people. The west coast of North America, which gets much of its water from glaciers in mountain ranges such as the Rocky Mountains and Sierra Nevada, also would be affected.
By far the largest part of Australia is desert or semi-arid lands commonly known as the outback. In June 2008 it became known that an expert panel had warned of long term, possibly irreversible, severe ecological damage for the whole Murray-Darling basin if it does not receive sufficient water by October. Water restrictions are currently in place in many regions and cities of Australia in response to chronic shortages resulting from drought. The Australian of the year 2007, environmentalist Tim Flannery, predicted that unless it made drastic changes, Perth in Western Australia could become the world’s first ghost metropolis, an abandoned city with no more water to sustain its population. However, Western Australia's dams reached 50% capacity for the first time since 2000 as of September 2009. As a result, heavy rains have brought forth positive results for the region. Nonetheless, the following year, 2010, Perth suffered its second-driest winter on record and the water corporation tightened water restrictions for spring.
Effects on climate 
Aquifer drawdown or overdrafting and the pumping of fossil water increases the total amount of water within the hydrosphere subject to transpiration and evaporation processes, thereby causing accretion in water vapour and cloud cover, the primary absorbers of infrared radiation in the earth's atmosphere. Adding water to the system has a forcing effect on the whole earth system, an accurate estimate of which hydrogeological fact is yet to be quantified.
Construction of wastewater treatment plants and reduction of groundwater overdrafting appear to be obvious solutions to the worldwide problem; however, a deeper look reveals more fundamental issues in play. Wastewater treatment is highly capital intensive, restricting access to this technology in some regions; furthermore the rapid increase in population of many countries makes this a race that is difficult to win. As if those factors are not daunting enough, one must consider the enormous costs and skill sets involved to maintain wastewater treatment plants even if they are successfully developed.
Reduction in groundwater overdrafting is usually politically very unpopular and has major economic impacts to farmers; moreover, this strategy will necessarily reduce crop output, which is something the world can ill-afford, given the population level at present.
At more realistic levels, developing countries can strive to achieve primary wastewater treatment or secure septic systems, and carefully analyse wastewater outfall design to minimise impacts to drinking water and to ecosystems. Developed countries can not only share technology better, including cost-effective wastewater and water treatment systems but also in hydrological transport modeling. At the individual level, people in developed countries can look inward and reduce overconsumption, which further strains worldwide water consumption. Both developed and developing countries can increase protection of ecosystems, especially wetlands and riparian zones. These measures will not only conserve biota, but also render more effective the natural water cycle flushing and transport that make water systems more healthy for humans.
A range of local, low-tech solutions are being pursued by a number of companies. These efforts center around the use of solar power to distill water at temperatures slightly beneath that at which water boils. By developing the capability to purify any available water source, local business models could be built around the new technologies, accelerating their uptake.
Global experiences in managing water crisis 
||This section is written like a personal reflection or opinion essay rather than an encyclopedic description of the subject. (September 2009)|
It is alleged that the likelihood of conflict rises if the rate of change within the basin exceeds the capacity of institution to absorb that change. Although water crisis is closely related to regional tensions, history showed that acute conflicts over water are far less than the record of cooperation.
The key lies in strong institutions and cooperation. The Indus River Commission and the Indus Water Treaty survived two wars between India and Pakistan despite their hostility, proving to be a successful mechanism in resolving conflicts by providing a framework for consultation inspection and exchange of data. The Mekong Committee has also functioned since 1957 and survived the Vietnam War. In contrast, regional instability results when there is an absence of institutions to co-operate in regional collaboration, like Egypt’s plan for a high dam on the Nile. However, there is currently no global institution in place for the management and management of trans-boundary water sources, and international co-operation has happened through ad hoc collaborations between agencies, like the Mekong Committee which was formed due to an alliance between UNICEF and the US Bureau of Reclamation. Formation of strong international institutions seems to be a way forward - they fuel early intervention and management, preventing the costly dispute resolution process.
One common feature of almost all resolved disputes is that the negotiations had a “need-based” instead of a “right–based” paradigm. Irrigable lands, population, technicalities of projects define "needs". The success of a need-based paradigm is reflected in the only water agreement ever negotiated in the Jordan River Basin, which focuses in needs not on rights of riparians. In the Indian subcontinent, irrigation requirements of Bangladesh determine water allocations of The Ganges River. A need based, regional approach focuses on satisfying individuals with their need of water, ensuring that minimum quantitative needs are being met. It removes the conflict that arises when countries view the treaty from a national interest point of view, move away from the zero-sum approach to a positive sum, integrative approach that equitably allocated the water and its benefits.
See also 
- Peak water
- Irrigation in viticulture
- Water contamination
- Water resources
- Water scarcity in Africa
- Drought rhizogenesis
- 1998 Klang Valley water crisis
- Arable land
- California Water Wars
- Chinese water crisis
- Consumptive water use
- Deficit irrigation
- Green Revolution
- Life Saver bottle
- Living Water International
- Ogallala Aquifer
- Water resource policy
- Spragg Bag
- Sustainable development in an urban water supply network
- Seawater Greenhouse
- Water conflict
- Water footprint
- Water resource policy
- WaterPartners International
- Freshwater: lifeblood of the planet
- Falkenmark and Lindh 1976, quoted in UNEP/WMO. "Climate Change 2001: Working Group II: Impacts, Adaptation and Vulnerability". UNEP. Retrieved 2009-02-03.
- Samuel T. L. Larsen. "Lack of Freshwater Throughout the World". Evergreen State College. Retrieved 2009-02-01.
- FAO Hot issues: Water scarcity
- The World Bank, 2009 "Water and Climate Change: Understanding the Risks and Making Climate-Smart Investment Decisions". pp. 21–24. Retrieved 2011-10-24.
- Molden, D. (Ed). Water for food, Water for life: A Comprehensive Assessment of Water Management in Agriculture. Earthscan/IWMI, 2007.
- Chartres, C. and Varma, S. Out of water. From Abundance to Scarcity and How to Solve the World’s Water Problems FT Press (USA), 2010
- http://www.nytimes.com/2009/10/02/science/earth/02drought.html NYTimes 2009 - Columbia University
- "United Nations statement on water crisis". Un.org. 2006-02-20. Retrieved 2011-03-10.
- UN World Summit on Sustainable Development addresses the water crisis[dead link]
- "No global water crisis - but may developing countries will face water scarcity", FAO.org 12 March 2003
- "Progress in Drinking-water and Sanitation: special focus on sanitation". MDG Assessment Report 2008 (WHO/UNICEF Joint Monitoring Programme for Water Supply and Sanitation). July 17, 2008. p. 25.
- "Updated Numbers: WHO-UNICEF JMP Report 2008". Unicef.org. Retrieved 2011-03-10.
- "Water is Life - Groundwater drawdown". Academic.evergreen.edu. Retrieved 2011-03-10.
- WaterPartners International: Learn about the Water Crisis
- "All About: Water and Health". CNN. December 18, 2007.
- Water, a shared responsibility. The United Nations World Water Development Report 2, 2006
- "Public Services"]". Gapminder video.
- Fredrik Segerfeldt (2005), "Private Water Saves Lives", Financial Times 25 August
- David Zetland, "Running Out of Water"
- David Zetland, "Water Crisis"
- "Looming water crisis simply a management problem" by Jonathan Chenoweth, New Scientist 28 Aug., 2008, pp. 28-32.
- "U.S. Water Supply". Fairus.org. Retrieved 2011-03-10.
- Jul 21, 2006 (2006-07-21). "India grows a grain crisis". Atimes.com. Retrieved 2011-03-10.
- "Water Scarcity Crossing National Borders". Earth-policy.org. 2006-09-27. Retrieved 2011-03-10.
- Water Shortages May Cause Food Shortages
- Yemen's Capital Facing Water Shortage Due to Rapid Increase in Population[dead link]
- "The Food Bubble Economy". I-sis.org.uk. 2002-04-12. Retrieved 2011-03-10.
- "Vanishing Himalayan Glaciers Threaten a Billion". Planetark.com. 2007-06-05. Retrieved 2011-03-10.
- Bagla, Pallava (December 5, 2009). "Himalayan glaciers melting deadline 'a mistake'". BBC. Retrieved 2009-12-12.
- Big melt threatens millions, says UN[dead link]
- "Ganges, Indus may not survive: climatologists". Rediff.com. 2004-12-31. Retrieved 2011-03-10.
- email@example.com (2007-07-24). "Glaciers melting at alarming speed". English.peopledaily.com.cn. Retrieved 2011-03-10.
- Singh, Navin (2004-11-10). "Himalaya glaciers melt unnoticed". BBC News. Retrieved 2011-03-10.
- "Glaciers Are Melting Faster Than Expected, UN Reports". Sciencedaily.com. 2008-03-18. Retrieved 2011-03-10.
- Water shortage worst in decades, official says, Los Angeles Times
- Bryant, Nick (June 18, 2008). "Australian rivers 'face disaster'". BBC News. Retrieved December 2, 2011.
- Ayre, Maggie (May 3, 2007). "Metropolis strives to meet its thirst". BBC News. Retrieved December 2, 2011.
- "Dams at record levels". ABC News. 2009-09-15. Retrieved 2009-09-25.
- "More winter blues as rainfall dries up". ABC News. 2010-08-31. Retrieved 2011-01-13.
- "Saving water in spring". Water corporation (Western Australia). 2010-09-23. Retrieved 2011-01-13.
- Tapping A Market CNBC European Business, October 2008
Further reading 
- An International Food Policy Research Institute book about the intersection of water policy, globalization and food security: Ringler, C., Biswas, A., and Cline, S., eds. 2010. Global Change: Impacts on Water and Food Security. Heidelberg: Springer.
- Steven Solomon (c2010). Water: The Epic Struggle for Wealth, Power, and Civilization. Harper. p. 608. ISBN 978-0-06-054830-8.
- Alexander Bell (c2009). Peak Water : Civilisation and the world's water crisis. Edinburgh: Luath. p. 208. ISBN 1-906817-19-7.
- Peter H. Gleick, ed. (c2009). The World's Water 2008-2009: The Biennial Report on Freshwater Resources. Washington D.C. : Island Press. p. 402. ISBN 10: 1-59726-505-5 Check
- Maude Barlow (c2007). Blue covenant : the global water crisis and the coming battle for the right to water. New York : New Press : Distributed by W.W. Norton. p. 196. ISBN 978-1-59558-186-0.
- Richard Heinberg (c2007). Peak Everything: Waking Up to the Century of Declines. Gabriola, BC : New Society Publishers. p. 213. ISBN 978-0-86571-598-1.
- Engelbert, Ernest A., and Ann Foley Scheuring, ed. (c1984). Water Scarcity: Impacts on Western Agriculture. Berkeley: University of California Press.
- Jameel M. Zayed. "No Peace Without Water – The Role of Hydropolitics in the Israel-Palestine Conflict". London.
- The World Bank, (2010) Water and Climate Change: Understanding the Risks and Making Climate-Smart Investment Decisions.
|Wikibooks has a book on the topic of: Drinking water|
- "Beyond scarcity: Power, poverty and the global water crisis". United Nations Development Programme (UNDP). 2006.
- Water Availability and Use in the Arab World an infographic by Carboun
- Food exports can drain arid regions: Dry regions ‘export’ water as agricultural products 24.March.2012 Science News
- The World Bank's work and publications on water resources
- The Global Water Crisis - myHydros.org | Everything About Water
- BBC News World Water Crisis Maps
- International Action: Fighting the Water Crisis in Haiti
- World Water Council: Water Crisis[dead link]
- Food and Water Security under Global Change and Water Policy at the [http://www.ifpri.org/ International Food Policy Research Institute (IFPRI).
- China water crisis - Greenpeace China
- Water Wars: Multimedia coverage of East Africa's water crisis from CLPMag.org
- Water Crisis Information Guide - From Middletown Thrall Library. Subjects include: Drinking Water, Government Information, International Challenges and Efforts, Global Water Issues, Oceanography, Sea Levels, Desalination, Water Scarcity, Pollution and Contaminants, Conservation and Recycling, News and Special Reports, and library catalog subject headings for further research.
- Water and Conflict: Incorporating Peacebuilding into Water Development
- Raipur Water Crisis Website For World
- Water Wars: A Global Crisis - interview with Dr. Richard Schuhmann
- Water crisis explained in two mins.
- Without water, revolution "The Syrian regime ignored a devasting drought, radicalizing its citizens." Thomas Friedman opinion the Syrian civil war factors