While water is a renewable resource, it is also a finite resource at the same time, meaning that water does not renew itself at a sufficient rate for sustainable extraction. Although there is plenty of water on the planet, more than 99 percent of the earth’s water is unusable for humans, because it is found in icecaps, glaciers, oceans, soils, and floating in the atmosphere. Resulting in only .03 percent of water to be used by humans, located in the surface water of lakes, swamps, and rivers. Because of the scarcity of water, 1.1 billion people worldwide lack access to water, and 2.4 billion people have poor sanitation; diseases like cholera, typhoid fever, and other water-borne illnesses are an outcome. Over the years increasing population, growing agriculture, expanding industrialization and rising standards of living have increased the demand for fresh water (Hoekstra, Mekonnen, Chapagain, Richter, and Mathews 2012). Water scarcity is growing at a rapid pace around the world due to the overdraft of water by humans, climate change, and the growing demand for food.
Overdraft of Water
The central reason water is depleting at such a rapid pace is because it is withdrawn at a faster pace than replenished. Aquifers are underground bodies of rock through which water can quickly move. Aquifers are natural filters that trap particles and provide physical purification of the groundwater flowing through them, which makes for very clean, usable water (Varghese, Veettil, Speelman, Buysse, Van Huylenbroeck 2013, 64). Groundwater is the most significant source of usable, fresh water in the world and it is a valuable resource throughout the world, mostly in areas where lakes and river are scare or inaccessible. In the United States, groundwater is the drinking water for about half of the total residents. For agricultural needs in the United States, over 50 billion gallons of groundwater are used daily (United States Geological Survey 2003, 1). of the United States has been suffering from groundwater depletion for multiple years, but the increased demands on groundwater resources have overstressed aquifers in many areas (2). The reduction of groundwater aquifers is different around the world; in some parts of Europe, like Germany and the Netherlands, there is much more precipitation than evaporation, so there are high rates of groundwater recharge. Different parts of the world like Pakistan and Yemen produce little to no rainfall, so the groundwater aquifers are being used for drinking water and crop irrigation faster than it can be refilled (Gleeson, Wada, Bierkens, and van Beek 2012, 200). A lack of groundwater creates dangerous sinkholes as a result of depleted aquifers. For example, the resident near the Gulf of Mexico and Mexico City solely rely on aquifers. Parts of Mexico City are falling as the water table lowers and creates sinkholes that are destroying buildings and homes (Kaufmnn 2007). The weakening of the Colorado River and the Ogallala aquifer are examples of vast groundwater reserves that are being depleted. Water from the Ogallala aquifer is used for irrigation throughout the Great Plains in the United States, and so much water is being taken from this aquifer that there is no time for it to refill (Tillman, Gangopadhyay, and Pruitt 2017, 506). The Colorado River channels water south nearly 1500 miles into the Gulf of California. Starting in the 1920s, Western states began dividing up the water of the river, diverting the flow hundreds of miles to Los Angeles, San Diego, Phoenix, and other cities. The Colorado River now is the source of water from thirty million people in seven U.S. states and Mexico, with 70 percent of its water used to irrigate cropland, but it no longer reaches the sea (506). This river has become a perfect representation of what happens when humans use too much of a limited resource, it disappears.
Climate Change
Human development has an impact on water scarcity for two main reasons, climate change and changes in the environment. Earth’s climate changes periodically, however during the last century there has been a noticeable warming period that may not be entirely due to the natural cycle. Researchers believe that human activities may be playing a significant role in exacerbating the natural heating cycle. A continuing increase in the earth's average temperature could have a dramatic effect on the world as a whole. It is predicted that as the earth’s temperature rises, glaciers, ice sheets, and ice caps around the world will melt. Sea levels would increase by 7.4 meters if just the Greenland Ice Cap melted, which would then damaging low-lying coastlands (Kahil, Dinar, and Albiac 2015, 109).
The cars humans drive, the power plants humans operate, and the forest humans destroy are all reasons why climate change is due to human development. Over the last century, the burning of fossil fuels, like coal and oil, has increased the concentration of atmospheric carbon dioxide. The systems used to treat and move public water require large amounts of energy, produced mainly by burning fossil fuels. Also, bottled water is a significant contributor to gas emissions, since it takes fuel to make the plastic bottles and ship them around the world. Some changes in the environment from humans are creations of hardscapes, like concrete or asphalt. Concrete and asphalt cannot absorb water, so if an abundance of rainfall were to hit a place with concrete or asphalt, that area would be expected to flood. An example of that would be the flooding in Houston after Hurricane Harvey. Although Houston is far above sea level, the city is extremely flat and is filled with roads made of asphalt. When the city experienced all of the rainfall that came with the recent hurricane, the water could not be absorbed and had nowhere to drain, which is why there was such devastating flooding.
Demand for Food
The growth of population, along with the rising incomes in developing countries, is driving up the global food demand. From the last century, the amount of people in the world has quadrupled (United Nations 2017, 1). By 2050, the food demand is predicted to rise by upward amounts of 98% Meat production must increase by 196 million tons, oil crops will need to increase by 133 million tons, and cereal production will need to increase by 940 tons to meet global food demand. This means that farmers worldwide will need to improve crop production to feed the world’s growing population, which will also increase the amount of water used to develop and produce food. The agriculture industry is the primary user of groundwater and employs approximately 70 percent of the world’s freshwater supply (Zonderland-Thomassen, Lieffering, and Ledgard 2014, 262). Water is essential for many things regarding agriculture, like crop production, livestock, and food manufacturing, however, a majority of the water used by the agriculture industry is for irrigation to crops. Excessive watering can also increase soil salinity. Livestock farmers use water for drinking, washing animals, cleaning yards, and more. The water used for livestock is required all year round, unlike the water needed for irrigation. On average, for a single pound of beef, it takes 1800 gallons of water. That enormous water footprint is primarily due to the amount of water needed to grow the grass, feed the animals that the beef is coming from, and also drinking, cleaning, and processing. On average, an American eats 167 pounds meat a year, which adds up the amount of water needed to provide for the growing demand (Beghin, Meade, and Rosen 2017). Dairy farms also use significant amounts of water for cooling. In total, it takes about eight liters of water to produce one liter of milk. The leading causes of wasteful and unsustainable water use are broken irrigation systems, wasteful field application methods, and cultivation of thirsty crops not suited to the environment. Unsustainable water use harms the environment by altering the water table and depleting groundwater supplies.
The pollution created by agriculture is the leading source of water pollution to rivers and lakes surrounding farms. Increased nutrient loading from animal waste can lead to bodies of water, which may eventually damage aquatic ecosystems (Ahmed, Scholz, Al-Faraj, and Niaz 2016). Pesticides and fertilizers are the earliest sources of pollution. Once the crop has been sprayed, some of the pesticides mix with the water and seep into the ground, and the rest of it is absorbed by the plant. As a result, the groundwater has been contaminated, as well as the animals that eat these plants. Many of the most affected countries of water scarcity, such as the United States, China, India, Pakistan, Australia, and Spain, are big food producing countries. In China, some of the cities that are water stressed are Harbin, Ningbo, Xuzhou, and Qingdao. At least one-third of China’s lakes and rivers are unfit for human use, and 73 percent of China's watersheds face medium to high pollution levels (Liu and Kang 2006, 3-19). India has a population that is three time the size of the United States, but one-third the physical dimension. Not a single Indian city can provide clean water from the tap on a twenty-four-seven basis, as most Indian water bodies are now polluted with both bio and chemical pollutants, and not a single Indian city can provide clean water from the tap on a twenty-four-seven basis. The groundwater extraction keeps growing at an increasing rate since Indian law extends exclusive rights to landowners over groundwater, meaning many farmers are putting private tube-wells in their farms to irrigate their crops because of lack of reliable surface irrigation. The country is a major grain producer with a need for water to support agriculture (Varghese, Veettil, Speelman, Buysse, and Huylenbroeck 2013, 55-64). The result of water pollution will have an overall detrimental effect on the water quality and amount of clean water for years to come.
Conclusion
The population of the world is expected to be over 9 billion people by 2050 (United Nations 2017, 1). Drinking, hygiene, agriculture, energy, and industry are just some of the sectors that require the need for fresh water. Eighty countries are already suffering from water shortages, and 40 percent of the world does not have access to clean water (United States Geological Survey 2003). In many countries, like Jordan, Yemen, Pakistan, and parts of the United States, surface and groundwater are being used quicker than it can be replenished. Some bodies of water, such as the Colorado River, are drying out and lowering because too much water is being extracted from it. Climate change and changes in the environment is affecting the amount of usable water. Higher temperatures and shifting climate patterns may change the areas where crops grow best and also modify the natural plant communities, and the ocean water will expand if it warms, contributing to sea level rise. Finally, the increasing population is creating a growing demand for food. For countries to be able to feed the ever-increasing population, water needs to be better conserved, and new agricultural technologies need to be developed.