Water scarcity refers to a lack of water resources needed to meet demand for water usage in an area or region.
Most of the water covering Earth is salt water. Freshwater scarcity is a critical and growing environmental health concern in areas around the world. Although not all regions have too little water, the worldwide population quadrupled in 100 years (from about 1915 to 2015). Consumption of water also has increased since 2000. In the twentieth century, consumption increased in many regions, often in line with population increases. In many regions of the world, there are only basic water services within a 30-minute roundtrip, and even more people have to travel further. In other areas, unprotected wells and springs deliver water that is not treated.
Decreasing river flows and falling water tables are among global water scarcity issues. In the best situation, water naturally replaces itself through rain and snow and long-term deposits underground. Human altering of the natural cycle has led to less availability of water. Water that is available is not distributed equally around the world. Finally, water is critical to balancing climates and geography. These combined effects of too little water have led to global and national security and economic and global health issues.
People can survive several weeks without food, but only days without water. In addition, water helps grow and supply food and keep people and the environment sanitary. In many developing or poor countries, girls and women are the primary collectors of water for their households, often walking miles per day for up to six hours round trip to haul water from a source back home. Water scarcity affects health in many ways, including not having access to drinking water to maintain health and diseases caused by drinking water of poor quality. Water scarcity also can affect availability or safety of food when safe water is not available for growing crops.
Worldwide, about 2 billion people live in areas of water scarcity, and 700 million people in 43 countries are directly affected by water scarcity. Another 1.6 billion people live in areas too poor to distribute available water to where the people live. The United Nations (UN) also states that two-thirds of the global population experiences water scarcity at least one month each year. More than 1.2 billion people lack access to clean drinking water. UNICEF predicts that by 2040, water scarcity will affect 600 million children. Although water scarcity can occur anywhere, including the western part of the United States, the most affected regions are in parts of Africa and the Middle East.
On a broad level, water scarcity is caused by overuse of freshwater resources. Overuse is caused by population increases and changes in behavior or practices in use of water compared with availability. Climate change also is a cause of water scarcity as precipitation patterns change. Because of climate change, some regions will experience increasing water shortages, while others will experience more flooding—both have negative health consequences. Economics also can contribute to water scarcity, when regions are too poor to provide the infrastructure needed to sanitize and deliver fresh water to residents. In turn, this can harm local economies.
Human bodies need water to stay in balance. Important electrolytes help the body maintain functions needed to live and can be affected by taking in too little water. Dehydration is a major risk of water scarcity. Constipation is one sign or dehydration, as is lack of energy. Prolonged dehydration can lead to urinary infection and kidney failure, as well as life-threatening shock.
In addition to dehydration from lack of water, people in areas of water scarcity can get diseases from having to drink contaminated water. Diarrhea is a common problem caused by diseases in areas of water scarcity, and the illness can further deplete fluids from a person who already is dehydrated. Diarrhea is the third leading cause of death for children around the world. Other diseases that often occur in areas of poor water and sanitation are:
Dehydration is treated by gradually increasing fluids and managing symptoms and side effects. Some diseases, such as Guinea worm disease, have no preventative treatment or vaccine. People who live in areas of water scarcity also typically lack access to health care to treat diseases associated with poor water access or quality. Prevention of water scarcity and disease is more effective and economical in most cases.
The World Health Organization (WHO) leads global efforts to prevent disease transmission through water. WHO publishes water quality guidelines on drinking water and sanitation and helps test water treatment agents. The UN has included the issue of water scarcity in its Sustainable Development which seek to make clean, accessible water universally accessible and affordable for all by 2030. Several UN entities have produced frameworks for coping with water scarcity in agriculture and food security.
Problems with water quality or scarcity in the United States typically occur and are addressed at local levels. For example, in 2014, the city of Flint, Michigan, changed its supply source for city water from Lake Huron to the Flint River. This change led to corrosion in water pipes and leaching of lead and other contaminants into the city drinking water. State and local agencies developed emergency responses to address health consequences of water contamination and water scarcity at local levels. The CDC and other federal agencies produced a document for public health officials to use in dealing with drought and the associated health issues of water scarcity. The document includes information on assessing potential public health problems early and implementing and communicating strategies to prevent major health issues.
People who live in areas of water scarcity can die from the illnesses caused by poor or unavailable water. It is estimated that 1 million people are killed by water, sanitation, and hygiene-related diseases each year. The problem is of particular concern for infants and children in many dry and poor areas of the world. It is estimated that one child dies every 90 seconds from a water-related disease. Unless efforts are made to improve access to water in areas of scarcity, the problem will continue to grow. Efforts also must address conservation of water as a natural resource.
Climate change must also be addressed. Currently, monsoon patterns are becoming more variable and less dependable; both could have consequences for food production and exacerbate food insecurity. About 40% of people on Earth live near a coast. The ecoservices provided by those coasts sustain human health: filtering freshwater, providing habitat for fish food sources to grow, fishing livelihoods, and tourist investment. Rising averagesurface temperatures and climate change are altering coastal ecosystems in many regions of the world and the result is severe as seen in Cape Town, South Africa's “Day zero” water crisis.
Improving access to safe drinking water can prevent dehydration and diseases caused by poor water quality. Improving sanitation and personal hygiene also can prevent water-related diseases such as cholera. Treating water appropriately can help eliminate fluorides and contamination with bacteria or larvae. Educating people in areas of water scarcity can help prevent some infections, but the best prevention is increased access to water and improved water quality.
Water should be treated as a scarce resource, no matter the country or region. Preventing water scarcity and associated health effects requires using less water, making access to water more equitable, improving sanitation and hygiene, and improving systems of water resource management and technology for cleaning and distributing water around the world.
See also Drinking-water supply ; Dysentery ; Escherichia coli ; Flint water crisis ; Guinea worm disease ; Noroviruses ; Schistosomiasis .
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Teresa G. Odle, BA, ELS