Water scarcity is the lack of fresh water resources to meet water demand. It affects every continent and was listed in 2015 by the World Economic Forum as the largest global risk in terms of potential impact over the next decade.
It is manifested by partial or no satisfaction of expressed demand, economic competition for water quantity or quality, disputes between users, irreversible depletion of groundwater, and negative impacts on the environment. One-thirds of the global population (2 billion people) live under conditions of severe water scarcity at least 1 month of the year.
Half a billion people in the world face severe water scarcity all year round.Half of the world’s largest cities experience water scarcity
Water covers 70% of our planet, and it is easy to think that it will always be plentiful. However, freshwater—the stuff we drink, bathe in, irrigate our farm fields with—is incredibly rare. Only 3% of the world’s water is fresh water, and two-thirds of that is tucked away in frozen glaciers or otherwise unavailable for our use.
As a result, some 1.1 billion people worldwide lack access to water, and a total of 2.7 billion find water scarce for at least one month of the year. Inadequate sanitation is also a problem for 2.4 billion people—they are exposed to diseases, such as cholera and typhoid fever, and other water-borne illnesses. Two million people, mostly children, die each year from diarrheal diseases alone.
Many of the water systems that keep ecosystems thriving and feed a growing human population have become stressed. Rivers, lakes and aquifers are drying up or becoming too polluted to use. More than half the world’s wetlands have disappeared. Agriculture consumes more water than any other source and wastes much of that through inefficiencies. Climate change is altering patterns of weather and water around the world, causing shortages and droughts in some areas and floods in others.
At the current consumption rate, this situation will only get worse. By 2025, two-thirds of the world’s population may face water shortages. And ecosystems around the world will suffer even more.
The human population has successfully harnessed many of the world’s natural waterways—building dams, water wells, vast irrigation systems and other structures that have allowed civilizations to grow and thrive. But water systems are increasingly stressed, and some rivers, lakes and aquifers are drying up.
As humans continue to pump more carbon dioxide and other greenhouse gases into the atmosphere, patterns of weather and water will change around the world. Droughts will become more common in some places, floods in others. Glaciers and snow packs will disappear in some areas, affecting the freshwater supplies to those downstream communities. These changes will combine to make less water available for agriculture, energy generation, cities and ecosystems around the world.
Water pollution comes from many sources including pesticides and fertilizers that wash away from farms, untreated human wastewater, and industrial waste. Even groundwater is not safe from pollution, as many pollutants can leach into underground aquifers. Some effects are immediate, as when harmful bacteria from human waste contaminate water and make it unfit to drink or swim in. In other instances—such as toxic substances from industrial processes—it may take years to build up in the environment and food chain before their effects are fully recognized.
Agriculture uses 70% of the world’s accessible freshwater, but some 60% of this is wasted due to leaky irrigation systems, inefficient application methods as well as the cultivation of crops that are too thirsty for the environment in which they are grown. This wasteful use of water is drying out rivers, lakes and underground aquifers. Many countries that produce large amounts of food—including India, China, Australia, Spain and the United States—have reached or are close to reaching their water resource limits. Added to these thirsty crops are the fact that agriculture also generates considerable freshwater pollution – both through fertilizers as well as pesticides – all of which affect both humans and other species.
In the last 50 years, the human population has more than doubled. This rapid growth— with its accompanying economic development and industrialization—has transformed water ecosystems around the world and resulted in a massive loss of biodiversity. Today, 41% of the world’s population lives in river basins that are under water stress. Concern about water availability grows as freshwater use continues at unsustainable levels. Furthermore, these new faces also need food, shelter, and clothing, thus resulting in additional pressure on freshwater through the production of commodities and energy.
Some Important facts:
1. By 2020 about 30-40% of the world will have water scarcity, and according to the researchers, climate change can make this even worse. With only 7% of the world’s freshwater, China plans to produce 807 million gallons a day from desalination by 2020, roughly quadruple the country’s current capacity.
2. By 2025, an estimated 1.8 billion people will live in areas plagued by water scarcity, with two-thirds of the world’s population living in water-stressed regions.
3. According to the U.S. Intelligence Community Assessment of Global Water Security, by 2030 humanity’s “annual global water requirements” will exceed “current sustainable water supplies” by 40%.
4. The global middle class will surge from 1.8 to 4.9 billion by 2030, which will result in a significant increase in freshwater consumption.
5. Water demand in India will reach 1.5 trillion cubic meters in 2030 while India’s current water supply is only 740 billion cubic meters.
6. By 2035, the world’s energy consumption will increase by 35 percent, which in turn will increase water use by 15 percent according to the International Energy Agency.
7. By the year 2040 there will not be enough water in the world to quench the thirst of the world population and keep the current energy and power solutions going if we continue doing what we are doing today.
8. The number of people living in river basins under severe water stress is projected to reach 3.9 billion by 2050, totaling over 40% of the world’s population.
9. The next time you open a can of soft drink, consider where the water inside it came from. The H20 in an Indian can of Coca-Cola includes treated rainwater, while the contents in the Maldives may once have been seawater. The water needs to come from such different sources for a reason – it’s because there is a global freshwater crisis.
10. By 2025, 1.8 Billion people will be living in countries or regions with absolute water scarcity, and two-thirds of the world population could be under stress conditions.
Given that 70% of the Earth’s surface is water, and that volume remains constant (at 1,386,000,000 cubic kilometres), how is a water shortage even possible? Well, 97.5% is seawater unfit for human consumption. And both populations and temperatures are ever-rising, meaning that the freshwater we do have is under severe pressure.
Things are changing globally. On the one hand, there is good news. As the discusion below on the 7th Millenium Goal indicates, fewer people globally lack access to potable water than they did 30 years ago. Indeed, the percentage was cut in half. On the other hand, long term trends are not encouraging.
Among the important facts emphasized by the Food and Agriculture Organization (FAO) are these two:
Water use has been growing at more than the rate twice of population increase in the last century.
The map on your right and its included commentary tells a more complex story. For more information from the FAO’s collected research on the global status and usage patterns of water.
Some key facts and projections are available from the UNWater webpage where important statistics and maps from various sources are collected:
Water withdrawals are predicted to increase by 50 percent by 2025 in developing countries, and 18 per cent in developed countries. (Source: Global Environment Outlook: environment for development (GEO-4) )
Over 1.4 billion people currently live in river basins where the use of water exceeds minimum recharge levels, leading to the desiccation of rivers and depletion of groundwater. (Source: Human Development Report 2006)
In 60 percent of European cities with more than 100,000 people, groundwater is being used at a faster rate than it can be replenished. (Source: World Business Council For Sustainable Development (WBCSD))
The role of agriculture, both as a source of groundwater depletion due to water-intensity farming and animal husbandry techniques and as an object of special concern as water access becomes more difficult in some regions, will be an important part of the evolving global story about water resource supply and distribution.