Water scarcity

Water scarcity is when there isn’t enough fresh water for people and nature in a place. It can happen in two main ways. Physical water scarcity means there just isn’t enough water, like in deserts such as Central Asia, West Asia, and North Africa. Economic water scarcity happens when there isn’t enough money for tools and technology to get water from rivers or aquifers. This is common in parts of sub-Saharan Africa.

Even though Earth has a lot of fresh water, scarcity happens because of where and when water is needed. This can be caused by more people, changes in what people eat, more irrigated agriculture, climate change, droughts, floods, deforestation, water pollution, or using too much water.

Many people face water scarcity. Half of the world’s largest cities deal with it too. There are ways to help, like better water conservation, reusing wastewater, desalination, and working together between countries.

Definitions

Water scarcity means not having enough fresh water where and when people need it. There are two main types of water scarcity. One is called physical water scarcity, which happens when there simply isn't enough fresh water available in a place. The other is economic water scarcity, which happens when water exists but people can't get it because they can't afford it or there isn't good infrastructure to deliver it.

Some people also talk about water stress, which is a broader idea about how much water there is and whether people can use it. Water stress can cause problems like conflicts over water and trouble growing enough food.

Types

There are two kinds of water scarcity. The first is physical water scarcity. This happens when there isn’t enough natural water for everyone’s needs. It often happens in very dry places where water is scarce. The second is economic water scarcity. This happens when there isn’t enough money or technology to get and share water, even if water is nearby.

Both kinds of water scarcity affect many people around the world. Better water systems and infrastructure can help, especially where people need clean water for their daily lives.

Challenges

Simple indicators

There are several ways to measure water scarcity. One way is to look at how much water people use compared to how much water is available. Another way is to use the water poverty index.

"Water stress" is a term used to describe water scarcity. Experts use it when talking about Sustainable Development Goal 6. A report in 2018 explained water stress as how much water is taken from rivers and lakes compared to how much water nature needs. This helps us understand how much pressure there is on water supplies.

One common way to measure water stress is the "Falkenmark Water Stress Indicator". This says a place is facing water stress when there is less than 1,700 cubic meters of water for each person every year. If there is between 1,700 and 1,000 cubic meters, there may be occasional water shortages. When there is less than 1,000 cubic meters per person, the area is experiencing water scarcity.

Renewable freshwater resources

Main article: List of countries by total renewable water resources

We can also measure water scarcity by looking at how much fresh water a country has each year. This helps us understand if a country might face water scarcity. However, this method has limits because it gives an average and does not show how hard it is for people, homes, or businesses to get water. Also, this method looks at the whole country and may not show problems in specific areas.

More sophisticated indicators

To better understand water scarcity, scientists look at many pieces of information. This includes how much water is in the soil, the quality of the water, and how much water nature needs. Since the early 2000s, scientists have used more advanced tools to study water scarcity. These tools help them see how water use changes over time and look at both the amount and quality of water. Successful studies bring together experts from different fields, such as water science and social science.

Available water

Main articles: Water resources, Fresh water, and Water supply

The United Nations says only a small part of Earth’s water — about 200,000 cubic kilometers — is fresh water that people can use. This is a tiny bit of all the water on our planet. Most of Earth’s water is salty, and some fresh water is hard to reach.

Fresh water is found in rivers, lakes, and under the ground in places called aquifers. Even though there is enough fresh water for everyone, some places don’t get enough because water isn’t shared equally. Also, as more people live on Earth and the climate changes, it becomes harder to find clean water.

Scale

Current estimates

In 2019, the World Economic Forum said water scarcity was a big global risk for the next ten years. Water scarcity means not having enough fresh water when people need it. This can happen in different ways, like not having enough water for everyone, or people disagreeing over who gets the water. Some places use up their underground water so much that it can’t be refilled, which hurts the environment.

Right now, about half of all people on Earth face serious water shortages for part of the year. And half a billion people don’t have enough clean water any day of the year. Many big cities also struggle with water shortages. Almost two billion people don’t have clean drinking water at all. The number of people dealing with water scarcity has gone up a lot over time.

Future predictions

During the 1900s, we used water much faster than the world’s population grew. By 2025, we will probably need even more water—about 50% more in places that are still growing, and 18% more in places that are already well off. For example, Africa might have hundreds of millions of people without fresh water. By 2025, nearly two billion people will live where there isn’t enough water, and most of the world could be struggling with water problems.

As the world gets hotter and we need more water, more people will be at risk. Wetlands—places where water collects—are drying up, which also makes water harder to find. Scientists think that by 2040, around 4.5 billion people could be affected by water shortages. With more people coming, we’ll also need more water to grow food. Some studies show that many underground water sources could run dry if we keep using them too fast.

Impacts

See also: Water security

Water supply shortages

See also: WASH

When water is not managed well, it can be hard to get enough clean water for everyone. A report from the United Nations said that water problems are often because of bad management, not because there isn’t enough water. They talked about issues like poor leadership and not enough money spent on water systems.

Many people around the world don’t have clean water. Without clean water, people can get very sick.

Environment

Using too much water can hurt nature. Lakes, rivers, and wetlands suffer when water is taken away. For example, the Aral Sea used to be one of the biggest lakes in the world, but it has shrunk a lot because of water being used for farming.

Wetlands are important homes for many animals, but they have disappeared in many places. When water is taken away, animals and plants lose their homes and this can harm the whole environment.

Potential for conflict

Other impacts include growing competition for water.^: 6  For example, water scarcity can cause problems in the Middle East and North Africa Region.

Causes and contributing factors

Population growth

Main article: Population growth

Years ago, people thought water would never run out. There were far fewer people, and they used less water because they ate less meat and used less water to grow food. Today, there are many more people, and we need more water for food, especially meat. By 2050, the world’s population may grow even larger.

With more people, we need more water for drinking, growing food, and industries. Many places, especially in developing countries, already struggle with not enough water. To solve this, we must learn to save water and reuse it. We also need to think about how climate change will affect water supplies.

In many big cities in Europe, people are using groundwater faster than it can refill.

Over-exploitation of groundwater

Main article: Groundwater

As more people need water, we are using groundwater — the water stored underground — more than ever. This is happening because people drink it and because farms use it to water crops. In dry places like northern China, Nepal, and India, groundwater is being used too fast. Some cities have seen their underground water levels drop by tens of meters.

Groundwater used to be used less, but new technology made it easier to reach. This helped farms grow more food, but now we’re taking out more water than can naturally return. If we keep doing this, the water will run out, and the land may sink. Groundwater also gives us almost half of our drinking water, and it helps during dry times when rain is scarce.

Expansion of agricultural and industrial users

Most water shortages happen because farms and factories use so much water. People in wealthier countries use much more water, often without realizing it, because the goods they buy — like fruits and clothes — needed lots of water to make. Many water sources are used up faster than they refill, and some water is too dirty to use.

To prevent big water problems, farms need to grow more food with less water, and factories and cities need to use water wisely. As the world uses more energy, it will also need more water, which could put even more pressure on our water supplies.

Water pollution

Climate change

Further information: Effects of climate change on the water cycle and Water security § Climate change

Climate change can change how much water there is and where it goes. Warmer temperatures will make water evaporate faster and change how much rain falls. Some places may get too little rain and face droughts, while others may get too much and have floods. Mountains may have less snow and more rain, which changes how water flows downhill.

Climate change may also make water harder to use because it can affect water quality. It may also mean farms need more water to keep crops growing. Scientists have found that having more people is a bigger problem for water shortages than changes in climate over long periods.

Options for improvements

Main articles: Water resource management and Integrated water resources management

A report from 2006 said it is hard to know if water is really scarce around the world (a supply issue) or if it is just not used well (a demand issue).

The International Resource Panel of the UN says that governments have spent a lot on big projects like dams, canals, aqueducts, pipelines and water reservoirs. These are often not good for the environment or the economy. The panel suggests that the best way to use water wisely is for governments to make holistic water management plans. These plans should look at the whole water cycle, from where it comes from to how it is used, treatment, recycling, and how it goes back to nature.

In general, there is enough water in the world each year. The problem is that water does not always come at the right time or in the right places. Good planning and smart use of water can help solve these problems. Both ways of managing water—adding more sources and using less—have good and bad points.

Further information: Water conflict and International waters

When countries do not work together, it can lead to water conflicts. This is often a problem in developing countries. One big reason is arguments about how much water is available and how it should be used. For example, Egypt and Ethiopia had a big argument over the Grand Ethiopian Renaissance Dam starting in 2020. Egypt worried the dam would give it less water from the Nile.

Regional examples

The Consultative Group on International Agricultural Research made a map showing places that are running low on water. These include North Africa, the Middle East, India, Central Asia, China, Chile, Colombia, South Africa, Canada and Australia. Water shortages are also getting worse in South Asia.

More developed places like North America, Europe and Russia are not expected to have big water problems by 2025. This is partly because they have more money. But places like North Africa, the Middle East, South Africa and northern China will have very serious water shortages. This is because there simply isn’t enough water for the number of people living there. Most of South America, Sub-Saharan Africa, southern China and India will also face water shortages by 2025. This is because these places don’t have enough money to make clean drinking water.

Water shortages are a big problem in Yemen. The causes include population growth, changes in the climate, poor water management, less rain, and problems with water infrastructure. By 2015, Yemen was one of the places with the worst water shortages. Most people in Yemen don’t have enough water for at least one month every year.

In Nigeria, very hot weather, long periods without rain, and the shrinking of Lake Chad are causing water shortages. This is making thousands of people leave their homes.

A big study in 2019 found that glaciers in the Himalayan mountains could lose a lot of their ice by 2100. These glaciers feed major rivers like the Ganges, Indus, Brahmaputra, Yangtze, Mekong, Salween and Yellow. About 2.4 billion people live near these rivers. Countries like India, China, Pakistan, Bangladesh, Nepal and Myanmar might face big floods followed by long dry periods in the future.

Even though China is pumping out a lot of water from deep underground, it is still not enough. Most of the 3 billion more people expected on Earth by mid-century will be born in countries that already don’t have enough water.

It is very likely that changes in the climate will cause southern parts of Turkey to run low on water before 2070, and droughts will become more common in Turkey.

In the Rio Grande Valley, large farms have made water shortages worse. This has caused arguments about who has the right to use the water between Mexico and the United States.

The west coast of North America gets a lot of its water from glaciers in mountain ranges like the Rocky Mountains and Sierra Nevada.

Australia is mostly desert or dry land. Because of long periods without rain, many places and cities in Australia have rules about how much water people can use. One expert said that Perth in Western Australia might become a city with no people because it will run out of water.

Some countries have shown that it is possible to use less water even while their economies grow. For example, Australia used 40% less water between 2001 and 2009 while its economy grew by more than 30%.

Society and culture

Global goals

Main article: Sustainable Development Goal 6

Sustainable Development Goal 6 aims to ensure everyone has clean water and sanitation. It is one of 17 important goals set by the United Nations General Assembly in 2015. One of its aims is to improve water use and ensure enough clean water for all, especially in places where water is scarce.