Water covers 71% of the Earth's area, making it one of the most abundant natural resources by volume. However, over 97% of the Earth's water can be found in the oceans. Ocean water is brackish, meaning it contains many minerals such as salt and is hence known as saltwater. A mere 2.78% of the world's water exists as freshwater, which can be used by humans, animals, and for agriculture. The abundance of saltwater versus the scarcity of freshwater is a global water resource problem that humans are working to solve.
Freshwater is often in high demand as a water resource for human and animal consumption, industrial operations and as irrigation for agriculture. Three-quarters of freshwater can be found in ice and glaciers, rivers, freshwater lakes such as North America's Great Lakes and in Earth's atmosphere as water vapor. The rest of Earth's freshwater can be found deep inside the ground in aquifers. All of Earth's water circulates in various forms depending on its place within the hydrologic cycle.
Freshwater Uses and ConsumptionNearly three-quarters of freshwater consumed in a single given year is used for agriculture. Farmers who wish to grow water-loving crops in semi-arid area divert water in from another area, a process known as irrigation. Common irrigation techniques range from dumping buckets of water onto crop fields, diverting water from a nearby river or stream by digging channels to farm fields or pumping a supply of groundwater to the surface and bringing it to the fields though a pipe system. Industry also relies much upon freshwater supply. Water is used in everything from wood harvesting for making paper to processing petroleum into gasoline for automobiles. Domestic consumption of water makes up the smallest portion of freshwater use. Water is used in landscaping to keep lawns green and is used for cooking, drinking and bathing.
Water Overconsumption and Water AccessAlthough freshwater as a water resource might be plentiful and fully accessible to some populations, for others this is not the case. Natural disasters and atmospheric and climate conditions can cause drought, which can be problematic for many who rely on a steady supply of water. Arid areas around the world are most vulnerable to drought due to high annual variations in rainfall. In other cases water overconsumption can lead to problems that affect entire regions both environmentally and economically.
Efforts to promote agriculture in semi-arid Central Asia during the mid- and late-20th century depleted the the Aral Sea's water significantly. The Soviet Union wanted to grow cotton in relatively dry parts of Kazakhstan and Uzbekistan so they constructed channels to divert water away from rivers to irrigate crop fields. As a result, water from the Syr Darya and Amu Darya reached the Aral Sea with significantly less volume than before. Exposed sediments from the formerly submerged sea bed scattered in the wind, causing damage to crops, nearly eliminating the local fishing industry, and negatively affected the health of the local residents, all putting excessive strain on the region economically.
Accessing water resources in under-served areas can also cause problems. In Jakarta, Indonesia residents who receive water from the city's pipe system pay a small fraction of what other residents pay for lesser quality water from private vendors. Consumers of the city's pipe system pay less than the price of supply and storage, which is subsidized. This similarly occurs worldwide in areas where water access greatly varies in a single city.
Water Management SolutionsConcerns about long-term water shortages in the American West have brought about several approaches for a solution. Drought conditions occurred in California for several years during the middle part of the first decade of the 21st century. This left many farmers statewide concerned about irrigating their crops. Efforts by private agencies to deposit and store excess groundwater during wetter times allowed for distribution to farmers during the drought years. This type of water lending program, known as a drought bank, brought much needed relief to concerned farmers.
Another solution for water resource shortages is desalination, which turns saltwater into freshwater. This process, as described by Diane Raines Ward in her book Water Wars has been used since the time of Aristotle. Seawater is often boiled, the steam produced is captured and separated from the remaining salt and other minerals in the water, a process known as distillation.
Additionally, reverse osmosis can be used to create freshwater. The seawater is filtered through a semipermeable membrane, which sieves out salt ions, leaving behind freshwater. While both methods are highly effective in creating freshwater, the desalination process can be quite expensive and require a great deal of energy. The desalination process is mainly used for creating drinking water rather than for other processes such as agricultural irrigation and industry. A few countries such as Saudi Arabia, Bahrain and the United Arab Emirates rely heavily on desalination for creating drinking water and utilize the majority of the current desalination processing plants.
One of the most effective methods to manage existing water supplies is conservation. Technological developments have helped farmers build more effective irrigation systems for their fields where runoff can be recovered and used again. Regular audits of commercial and municipal water systems can help identify any problems and potential for reduced efficiency in processing and delivery. Educating consumers about household water conservation can help decrease household consumption and even help keep prices down. Thinking of water as a commodity, a resource meant for proper management and wise consumption will help ensure a constantly available supply worldwide.