What is physical water scarcity, and what is economic water scarcity
The same word, scarcity, describes 2 different failures. Physical water scarcity means there is not enough water in a place to meet every demand on it, including what rivers and wetlands need to keep flowing, the Food and Agriculture Organization states. Economic water scarcity means water exists, but the money, pipes, pumps or institutions needed to move it to people are missing, the same 2012 report states. Much of sub Saharan Africa falls into the second category, the report states.
These are 2007 figures still carried on the United Nations page today, not a current year count.
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| Physical water scarcity | 1.2 |
| Approaching physical scarcity | 0.5 |
| Economic water shortage | 1.6 |
A United Nations page still carries the clearest global head count of both groups, traced to a 2007 joint factsheet from United Nations Water and the Food and Agriculture Organization. It states 1.2 billion people lived under physical water scarcity that year and 1.6 billion faced economic water shortage. Neither figure has been recalculated since, so this is a 2007 estimate still carried on the page today, not a current count.
The Food and Agriculture Organization has already changed its own framework once
The physical versus economic distinction above is not the current position of the organization that built it. Its current water scarcity page splits the idea into 3 categories instead, physical, access and infrastructure scarcity, and never uses the word economic. This is not a numbers dispute, it is the same institution changing its own definition over time, visible only by reading both documents directly. The 2012 framework runs here because it is fuller and better established.
How water stress is measured, and where it is worst today
Physical scarcity has its own scale. The Falkenmark water stress index counts the cubic meters of renewable freshwater available a person each year. Below 500 is absolute water scarcity. Between 500 and 1,000 is chronic water shortage. Between 1,000 and 1,700 is regular water stress, the Food and Agriculture Organization states, a scale the United Nations page repeats unchanged.
The open ended top category, occasional or local water stress, over 1,700 cubic meters, has no upper bound in the source and is left off the chart rather than inventing one.
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| Top of absolute water scarcity | 500 |
| Top of chronic water shortage | 1,000 |
| Top of regular water stress | 1,700 |
The Middle East and North Africa is the clearest present day example of physical scarcity. 83% of the region population faces extremely high water stress today, and the World Resources Institute projects that share will reach 100% by 2050. South Asia follows at 74%. At least 50% of the world population, around 4 billion people, lives under highly water stressed conditions, the Institute states. This is a different measurement than the 2007 split above, and the 2 figures should never be added together.
The World Resources Institute projects the Middle East and North Africa share will reach 100% by 2050.
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| World | 50 |
| South Asia | 74 |
| Middle East and North Africa | 83 |
All are places where shortages of water contribute to poverty. They cause social hardship and impede development. They create tensions in conflict-prone regions.
Ban Ki moon, then serving as United Nations Secretary General, speaking of places facing water shortages. Source 2.
What fixes each kind of scarcity is different
The distinction matters because the fix differs. A region with physical water scarcity needs new supply, recycling or lower demand. A region with economic water scarcity needs investment instead, a solvable, financed problem rather than a hydrological one, the Food and Agriculture Organization states of sub Saharan Africa. Ethiopia illustrates the economic case, 76% of the population lacks access to an improved water supply, the World Bank states, and the Sahel region of Africa irrigates less than 1% of its cultivated land.