A world of urban deserts
Between 1964 and 2019, global population more than doubled from 3.26 billion to 7.7 billion. Worldwide water consumption also more than doubled during this time frame.
According to the World Resources Institute, 17 countries are designated “extremely high” water risk — that is, they are using almost all of their available water. Among these are Qatar, Israel, Lebanon, the Palestinian territories, Iran and India. Another 27 are designated “high” water risk. Collectively these 44 countries account for 25% of global population — 1.93 billion people.
India is facing the worst water shortage in its history. With 4% of global fresh water and 15% of the world’s population (1.4 billion and increasing) this shortage will only get worse. Farmers across India and neighboring Pakistan are draining aquifers to grow water-intensive crops, such as cotton and rice, faster than the water can be replenished.
The water-shortage crisis is especially acute in cities, most notably the planet’s giant metropolitan areas. This is the first “urban century” in human history as more than half of the world’s population now resides in cities. With global population projected to add 2.2 billion people and reach 9.9 billion by 2050, three-quarters of the world population could live in cities. At the same time, one population projection states that in mid-century more than one in three cities worldwide will face a water crisis.
Fourteen of the world’s largest cities are currently experiencing water scarcity or drought conditions. A comprehensive study by the Indian government concluded that 21 cities in India could run out of water next year.
The two-year drought-stricken South African city of Cape Town barely escaped “Day Zero” (when it would run out of water) in 2018 by severe water rationing as daily water consumption was reduced from 100 gallons to 13 gallons per person. (One toilet flush uses between 1.3 and 3.5 gallons of water). The rains finally arrived, and Cape Town dodged a bullet — for now.
Mexico City is located in a valley largely devoid of above-ground water sources, and the local government is digging ever-deeper wells to meet the demands of the 21 million metropolitan inhabitants who consume 287 billion gallons of water annually. The digging is weakening ancient clay beds the city was constructed on, resulting in the ground sinking as much as 3 feet a year in some neighborhoods. As a consequence of extreme heat, in 2018 more than 900,000 Mexico City residents had no running water. Almost 400 tanker trucks were making three trips a day to supply people with this life-sustaining liquid.
There are four major contributing factors to the global urban water crisis.
¯ Population growth — While global population increase is slowing, in the poorest regions of the world — especially Africa — birth rates remain high, fueling population growth. Africa’s population is projected to double from 1.3 billion in 2018 to 2.6 billion in 2050, and most of this increase will be in cites. (To put the 2.6 billion number in perspective, global population in 1960 was 3 billion).
¯ Rural-to-urban migration — Cities are attracting migrants today in unprecedented numbers, and combined with natural population increase (more births than deaths) in urban areas, this migration significantly contributes to both the making and growth of giant cities. Lagos, Nigeria, had a population of 1.4 million in 1970 and 21 million in 2018. At this rate of increase, Lagos is projected to have 42 million residents by 2050 and become the world’s third largest city. Where will the water come from for a metropolis with a population greater than that of present-day California (40 million people)? With high birth rates and ever-increasing rural-to-urban migration, it’s hardly surprising that of the world’s 100 fastest-growing cities, 86 are in Africa.
¯ Climate change — As a consequence of climate change, the earth’s “hydrological cycle,” or water cycle, is altering when, where and how much precipitation falls. When rainfall become more erratic the water supply is less reliable, and as the days grow hotter more water evaporates from urban reservoirs just as the demand for water increases. NASA climate scientist Benjamin Cook notes that “climate change is already making many parts of the world drier and droughts are likely to pack more punch as the climate warms further.”
¯ Food production — Globally, agriculture accounts for 70 to 80% of all fresh water use. Global population is expected to increase by more than 2 billion over the next 30 years, requiring agriculture water use to rise sharply. As farmers draw more water from aquifers, river, lakes and streams, there will be less water for city dwellers.
Although the urban water crisis has not significantly affected North America to date, a number of U.S. cities are particularly vulnerable to water shortages, including Los Angeles, Phoenix, Atlanta, Miami and El Paso. Most of the water required for sprawling Los Angeles County (10 million residents) comes from Northern California and the Colorado River, both susceptible to drought. Likewise, metropolitan Atlanta (population 6 million) gets most if its water from the Chattahooche River basin and smaller rivers, all of which have been affected by prolonged dry weather.
Located in the Chihuahuan Desert, El Paso, with almost 700,000 residents, receives only 9 inches of rainfall a year. The city obtains its drinking water from the Rio Grande River, now called the “Rio Sand” in some places. The precarious water situation in Phoenix (1.6 million residents) is best summarized by the city’s water resource manager: “We’re sitting in the middle of the desert trying to grow a city.”
With rising sea levels, salt water is leaking into and contaminating Miami’s fresh water supply. There is also concern that, as a result of climate-change-induced flooding, toxic chemicals from Miami-Dade County’s Superfund sites could spill into aquifers.
Desalinized sea water may be viable for drinking and household use in the world’s wealthier countries, but not for agriculture. Desalinization is fraught with problems. First, it is incredibly expensive. As of 2017, desalinized water in California’s Central Valley was 275 times more expensive than available groundwater — far beyond the means of developing countries where the fresh water crisis is most acute.
A Scientific American report states that large-scale desalinization would have a significant negative impact on ocean biodiversity. Intake pipes vacuum up and inadvertently kill millions of plankton, fish eggs, fish and other microbial organisms that comprise the bottom layer of the marine food chain. For every gallon of salt-free water produced, there is another gallon of “doubly concentrated salt water” that can alter fragile marine ecosystems if not disposed of correctly.
Finally, powered by fossil fuels, desalinization plants contribute to global warming and the shortage of fresh water that warming produces.
Currently, our best response to the growing global water gap is a planet with oceans of water too costly for all but the wealthy to drink.
George J. Bryjak lives in Bloomingdale and is retired after 24 years of teaching sociology at the University of San Diego.
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