Long-term shortage of water

Water scarcity is no longer a distant threat but a pervasive and worsening global reality. While often perceived as an arid-region issue, it now affects every continent, driven by a combination of climate change, population growth, economic expansion and mismanagement.  In some areas, further economic growth will not be possible until adequate additional water supplies become available. In other areas, failure to increase the water supply may well result in standards of living being reduced below present levels. Competition for water resources will heighten, arousing conflict. Countries with abundant water resources, may be subject to increasing demands to share or sell their resources.

The crisis manifests in two primary forms: physical scarcity (inadequate natural water resources) and economic scarcity (lack of infrastructure and governance).

The primary drivers of long-term water shortage are:

1. Climate Change: Alters precipitation patterns, intensifies droughts and floods, and accelerates glacial melt, reducing reliable freshwater storage. Recent multi-year "megadroughts" in regions like the southwestern US and the Mediterranean are far more severe due to anthropogenic warming.
2. Overconsumption & Demand Growth: Global freshwater use has increased sixfold over the past century and continues to rise at ~1% per year. Agriculture (~70% of withdrawals), industry (~19%), and municipal use (~12%) all contribute.
3. Pollution & Degradation: Contamination from agricultural runoff, industrial discharge, and inadequate wastewater treatment renders existing supplies unusable.
4. Governance & Infrastructure: Fragmented management, subsidized pricing, and aging, leaky distribution systems lead to massive inefficiencies and inequitable access.

All life depends on water but many societies have long been using water faster than it can be replenished annually in rivers and soils, as well as over-exploiting or destroying long-term stores of water in aquifers and wetlands.  As a result, many critical water systems are already bankrupt and no one knows exactly when the whole system would collapse.

Demand for water is growing several times faster than population, as agriculture, industrial and domestic uses increase. Global water use doubled between 1940 and 1980, and is due to double again by the year 2000.  About half this increase is caused by population growth.

World population is rising at present at an average rate of about 2% per annum, which means that, other factors being equal, world water demand will double about every thirty-five years. This demand, however, is further raised by the rise in the standard of living, leading to greater requirements for water for human consumption. This is brought about by the movement of population from primitive to modern housing, with water supply and bathrooms; by the rapid urbanization evident in all countries; and by numerous other factors.

Practically every increase in the production of goods – from rice to electricity and chemicals – requires increased quantities of water. The same applies to service industries, from commercial laundries to hotels. The increased demand for water resulting from the growth in the production of goods and the expansion in service industries is difficult to estimate because much will depend on the type of commodities to be produced and the type of service industries to be established. It should be noted, however, that the increased demand for water for the production of goods and services is independent of the increased demand for water for the population and is therefore additional to the latter.

Global use of energy has tripled during the past three decades. This places proportionate demands on water use. In some places the availability of water is becoming more of a constraint on hydroelectric energy production than the availability of primary fuel. A single coal gasification plant producing 7 million cubic meters of burnable gas per day would require as much as 25 million cubic meters of water a year. Obtaining and transporting the necessary water would be more damaging to the environment than strip-mining the coal itself.

• Global Baseline: According to the UN World Water Development Report 2023, 2–3 billion people worldwide experience water shortages for at least one month per year. This is projected to worsen, with global water demand expected to exceed supply by 40% by 2030.
• Middle East & North Africa (MENA): The world's most water-stressed region. All 17 of the world's most water-stressed countries are here, including Qatar, Israel, Lebanon, Iran, and Jordan, where agriculture, industry, and households use over 80% of available surface and groundwater.
• India: A 2020 NITI Aayog report warned that 21 major cities, including Delhi, Bangalore, and Chennai, could reach zero groundwater levels by 2030, affecting 100 million people. 40% of India's population will have no access to drinking water by 2030 under current trends.
• The Americas: The Colorado River Basin, serving 40 million people and 5.5 million acres of farmland, has been in a 23-year "megadrought"—the driest period in 1,200 years. States and Mexico face mandatory cuts. Similarly, chronic overuse has caused critical declines in the Ogallala Aquifer in the U.S. High Plains.
• Europe: Severe droughts in 2022 and 2023 affected over 60% of the EU and UK, straining agriculture, energy production (via reduced hydro and cooling water), and ecosystems. France, Spain, Italy, and Germany have faced recurring critical shortages.
• Africa: Chronic water stress in the Sahel and Horn of Africa is being exacerbated by prolonged drought. Lake Chad has shrunk by 90% since the 1960s, displacing communities and fueling conflict. In 2024, South Africa's major metros like Johannesburg implement severe water rationing amid systemic crises.

Global consumption of water is doubling every 20 years, more than twice the rate of human population growth. According to the United Nations, more than one billion people on earth lacked access to fresh water in 1999. By 2025, the demand for fresh water is expected to be 56 percent more than available; and that 1.8 billion people will live with dire water shortages and two-thirds of the world’s population could be living under stressed water conditions.

In 1990, a total of 28 countries with a population of 335 million people combined faced water shortage pressure or water scarcity. By 2025, between 46 and 52 countries will fall in this category. It is estimated that the overall population of those countries will increase to between 2.781 and 3.29 billion people in the next three decades depending on their population growth rates. The difference between these two figures is equal to 1.5 times the people which lived in 1990 under such circumstances.

A fifth of the world's population already lacks reliable access to clean water and, with birth rates climbing in many regions, the problem is becoming acute. In 1998 it was predicted that if present water resource planning was not changed, almost two thirds of humanity might suffer from moderate to serious water shortage before the year 2005.

According to one estimate, by the year 2000 one half of all the earth's annually renewed water – precipitated onto land – will be used by man. Unfortunately, because the actual availability of water bears little relationship to the distribution of population and demand, local shortages will become increasingly frequent as population and related consumption increase. Some 80 countries, with 40% of the world's population, already suffer serious water shortage. In the face of population growth, many developing countries are unable to reduce the numbers who are lacking adequate water supplies. This will cause special problems for some rapidly growing cities.

In addition to problems of supply, the reliability of water flow is being disrupted in many areas as watersheds are deforested. More than half the population of developing countries, excluding China, lacks convenient access to safe water supplies. The resulting poor sanitation, in combination with undernutrition, accounts for the daily deaths of 40,000 infants and small children. Up to 10 million people died each year because of water-borne diseases such as typhoid and dengue fever.

About 70% of fresh water taken by human withdrawals was used for agriculture but millions of farmers are trying to grow more food from shrinking, polluted or disappearing water sources. Water bankruptcy in India or Pakistan, for example, also means an impact on rice exports to a lot of places around the world. More than half of global food is grown in areas where water storage was declining or unstable.

China's per capita water availability is one-third of the world's average and will drop as the population continues to increase. Industrial use of water almost doubled in the period between 1980 and 1993; in 1999 industry consumes 17 percent of China's total water supply. In 75 percent of China's cities, the demand for water exceeds the supply. Groundwater levels in the North China plain have been dropping by 1 to 2 metres per year. It is expected that China's demand for water will increase by 21 percent from 2000–2010.

Northern Africa and the Middle East would be particularly affected by severe constraints on water availability. The Arab oil rich countries such as Kuwait, Qatar, Bahrain, Saudi Arabia and the United Arab Emirates are five out of nine countries in the world which have the least per capita water resources. In Saudi Arabia, 90 percent of water resources being used for irrigation of agricultural lands come from the non-renewable underground water resources. If the resources continue to be exploited at the current rate of nearly 10 percent, they will totally run out in the next 10 to 20 years. To this end, the life span of Saudi Arabia's underground water resources has been estimated by the year 2007.

By the year 2100, Africa is projected to have a population five times that of today; the population of Asia is expected to double. During the next century, the amount of water available on a per capita basis will be reduced in Asia from the 1980 figure of 5100 cubic meters, to 2600; and in Africa from 9000 cubic meters per person, to 1600. These continental averages conceal striking regional differences. Even if sophisticated computer-based conservation and management and heavy irrigation schemes were introduced, water availability would not allow for more than a 50% increase in population in North Africa and the Middle East.

In many countries, such as Israel, supplies from groundwater are decreasing because of rapid withdrawals. In other countries, such as Bangladesh, most wells are polluted because of lack of sanitation; and in yet other countries, such as Egypt and Libya, overpumping from the ancient aquifers has allowed sea water from the Mediterranean to seep into the wells. This is also a problem in certain parts of Australia where, because of the increasing amounts of groundwater being withdrawn for irrigation, the water table is dropping and seawater is entering the aquifers, affecting water supplies for farms.