1. Water Scarcity

Water stressed areas are those where due to scarcity (lack of water available), water quality (water is polluted), or accessibility (infrastructure is available to supply water and/or people can afford to pay for clean water) there is risk that the available, clean freshwater is not enough to meet the demands on it. Agricultural water withdrawals have put significant pressure on freshwater resources globally, particularly in areas that are already water stressed.
There are a variety of ways to quantify water stress, but one way is to measure the ratio of water withdrawn from an area relative to the available water. This method focuses on the scarcity aspect of water stress. A region is water scarce if annual withdrawals are between 20% and 40% of the available water (surface and groundwater together). If withdrawals rise above 40%, the area is considered highly water scarce (Figure 2C.1.1) Regions such as much of the Middle East, Northern Africa, Southern Africa, and Southern Asia are all highly water scarcity. While this map shows water stress measurements averaged for an entire country, regional variations of water stress exist within countries, and it is estimated that 3.2 billion people live in agricultural areas that are water scarce. Of these, 1.2 billion live in areas with high water scarcity, the vast majority of which live in Southern, Eastern, and Southeastern Asia.
Map of the world showing water stress by country as a measure of ratio of water withdrawals to supply. Needed details of specific countries or regions are provided in the chapter text.
Figure 2C.1.1 Water stress as measured by ratio of water withdrawals to supply in 2019. Source: Genetics4Good (2019). GNU Free Documentation License 1.2. Found here.

While the United States is overall low to medium water stress (10-20%), there are large regions that are highly and extremely highly water stressed, ranging from 40% to over 80% in their ratio of withdrawals to supply (Figure 2C.1.2). These are mainly throughout the Colorado River Basin and the central and southern Great Plains, where there are major agricultural zones and minimal precipitation.

Map of the U.S. color coded to show water stress as described in the figure caption
Figure 2C.1.2 Water stress in the United States. Major agricultural areas in the central and western U.S. are areas of high or extremely high water stress. Source: Made using WRI Water Risk Atlas. CC BY-4.0. Found here.

Two main factors drive water stress: increasing demand and decreasing water availability. Demand is accelerating as population increases and as increasing economic development drives a requirement for more resources. Climate change is making water unpredictable and creating increased shortages. As these factors continue, water stress is expected to become more severe.

The impacts of water stress are not distributed evenly across the planet. Many countries do not have adequate water sterilization systems or monitoring systems to manage water resources properly and ensure availability for all. Poor and marginalized groups are typically the first to feel the effects of water stress, as the ability to access clean water is often more difficult for these groups due to rising costs and lack of water infrastructure systems. This directly impacts the ability to maintain good health, protect families, or even earn a living. For women and girls in some areas of the world, water scarcity means a longer walk to collect fresh water, potentially putting them in unsafe conditions or precluding them from having time for work or education. Lack of easily accessible water can be particularly harmful for pregnant women and babies.

Check your understanding: water stress vs. water scarcity

References

Food and Agricultural Organization of the United Nations, (2020). The State of Food and Agriculture 2020. https://doi.org/10.4060/cb1447en

License

Icon for the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

Environmental Geology Copyright © 2024 by Lindsay Iredale is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

Share This Book