what is water scarcity and what are its main causes?

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Water crisis is a general term used to describe a situation where the available water within a region is less than the region's demand. The term has been used to describe the availability of potable water in a variety of regions by the United Nations and other world organizations.^[1][2] Others, for example the Food and Agriculture Organization, said in 2003 that there is no water crisis but steps must be taken to avoid one in the future.^[3] The major aspects of the water crisis are allegedly overall scarcity of usable water^[4] and water pollution.

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 southwest 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 to 9.54 million from 6.48 million between 1990 and 2007.^[5] 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.”^[5] 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 that are very hard to predict because of the large amount of variables.

Lawrence Smith, the president of the population institute, asserts that although an overwhelming majority of the planet is composed of water, 97% of this water is constituted of saltwater; the freshwater used to sustain humans is only 3% of the total amount of water on Earth (Hoevel). Therefore, Smith believes that the competition for water in an overpopulated world would pose a major threat to human stability (Hoevel); indeed, world wars may be fought over the control of thinning ice sheets and nearly desiccated reservoirs.^[6] 2 billion people have gained access to a safe water source since 1990.^[7] The proportion of people in developing countries with access to safe water is calculated to have improved from 30 percent in 1970^[8] to 71 percent in 1990, 79 percent in 2000 and 84 percent in 2004, parallel with rising population. This trend is projected to continue.^[7]

The Earth has a limited supply of fresh water, stored in aquifers, surface waters and the atmosphere. Sometimes oceans are mistaken for available water, but the amount of energy needed to convert saline water to potable water is prohibitive today, explaining why only a very small fraction of the world's water supply derives from desalination.^[9]

There are several prinAquifer 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.cipal manifestations of the water crisis.

In India, from the 19th century onward, the paradigm of managing water has followed two interconnected routes.

One, the state took upon itself the role of sole provider of water. (It was the colonial state that centralized control over water resources. The post-independent state inherited this role, and continued with it.) Among other things, this led to communities and households being no longer the primary agents of water provision and management.

Two, the earlier use of rainwater and floodwater declined. In its place, there came a growing reliance on surface water (primarily rivers) and groundwater.

Today, the effects of this way of managing water are clearly visible:

• There is complete dependence on the state for any kind of water provision. It is a kind of fostered parasitism since the state, via its bureaucratic machinery, does not seem to possess the will to alter such a situation.
• Such has been the level of extraction from rivers that most of India's river basins have degraded and the rivers are polluted.
• Large dams are the major source of water storage, and canals are the major distributory route. The former have caused large-scale community displacement and ecological havoc. The latter, large-scale degradation of land via soil salinisation.
• Groundwater resources have been heavily over-used.

Thus water availability, both in terms of quality and quantity, has declined to such an extent that many parts of India, rural and urban, today face a drought-like situation. And when drought actually sets in, as it did in Gujarat and other parts of the country most recently in the year 2000, scarcity takes on a frightening visage. An already bleak reality seems even more grim...

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Water scarcityinvolveswater stress,water shortageordeficits, andwater crisis. The concept of water stress is relatively new.Water stressis the difficulty of obtaining sources of fresh water for use, because of depleting resources. Awater crisisis a situation where the availablepotable,unpollutedwaterwithin a region is less than that region's demand.

Unsustainable extraction of freshwater and other human interference with the water cycle are the immediate causes of water scarcity within a river basin.

Over-extraction has its most straightforward manifestation inthe level of aquifers, underground reserves charged by the passage of water through soil and rocks. If withdrawals exceed the natural rate of recharge, the level of an aquifer will fall, eventually drying up altogether.In parts of India, the water table is believed to have fallen more than 300 metres, the lack of control exacerbated by a policy of allowing farmers unlimited and free access to water.

Human intervention which degrades the quantity and quality of the natural supply of freshwater occurs in three principal ways.

Firstly, there are 48,000 large dams in place around the world, with many more under construction. Dams alter the natural flow of a river, often improving water and energy security for some, at the expense of others.

Secondly, soil moisture is lost in land degradation caused by poor farming practices and deforestation. And thirdly, surface waters are polluted by run-off of chemicals used in farming and by untreated industrial and household wastewater in cities. This is an acute problem in less developed countries where environmental and sanitation regulations remain inadequate.

In many countries of sub-Saharan Africa, there is an additional category of economic water scarcity which is caused by too little human intervention. This occurs when natural supplies are sufficient to meet demand but fail to reach users due to shortcomings in distribution or storage infrastructure.

Is this a story of water scarcity water scarcity is generally associated with the region having low rainfall or drought or prone areas