In the United States, many residents, but not all, are fortunate to have access to clean, fresh water every day. When they turn on the tap, plumbing systems instantly bring this important resource into their homes. Despite its importance for life, though, fresh water is an extremely rare resource on Earth. Less than three percent of the water found on Earth is fresh water, and the remaining 97 percent is salt water, such as what is found in the ocean.

Most of the world’s fresh water is not easily accessible to humans. Approximately 69 percent of Earth’s fresh water is locked away in the form of ice in glaciers and polar ice caps, and another 30 percent of Earth’s fresh water is under the surface in the form of groundwater. That leaves only about one percent of Earth’s fresh water as readily available for human use.

Unfortunately, the available surface fresh water is not equally distributed throughout the world. Brazil, Russia, Canada, Indonesia, China, Colombia, and the United States have most of the world’s surface freshwater resources. As a result, approximately one-fifth of the world’s population lives in water-scarce areas where, on average, each person receives less than 1,000 cubic meters (35,315 cubic feet) of water a year. This lack of water affects people’s access to clean, usable water, as well as the economic development and geopolitics of different areas.

Access to Water

Because freshwater resources are unequally distributed across the globe, many human populations do not have access to clean, safe drinking water. According to the United Nations, 2.1 billion people around the globe lacked access to safely managed drinking water in 2017. Instead, they had access only to contaminated water, which can carry pollution and infectious diseases; populations drinking dirty water are at increased risk of diarrhea, cholera, dysentery, and other diseases. Lack of access to clean drinking water leads to more than 3 million deaths every year.

As a result, providing improved water sources to developing countries is an important goal for international organizations. Between 1990 and 2015, 2.6 billion people worldwide gained access to improved water resources as a result of international efforts. The remaining human populations still without access to clean water are concentrated mostly in Africa and Asia, representing nearly 1 billion people.

Economic Development

Access to fresh water is also important for economic development. For example, freshwater sources enable the development of fisheries. People around the world harvest fish from these habitats, providing enough animal protein to feed 158 million people worldwide. These fisheries are both a source of subsistence for local fishermen and a source of income for traders.

Beyond the use of fresh water as a habitat, fresh water is also an important resource in other economic activities, such as agriculture. According to one estimate, about 70 percent of the world’s fresh water is used for agriculture. Farmers around the world use irrigation to transport water from surface and ground water sources to their fields. These agricultural activities involve over 1 billion people worldwide and generate over $2.4 trillion in economic value every year. In the future, demand for agricultural fresh water will only increase as global populations grow. According to one estimate, demand will increase by 50 percent by 2050. This increase in water use will put further strain on Earth’s limited freshwater supplies and make access to fresh water even more important.

Geopolitics

The fight over fresh water can already be seen today in international geopolitics. For example, Ethiopia and Egypt have long fought over Nile water resources in the Horn of Africa. The Nile River is an important waterway that supplies nearly 85 percent of Egypt’s water. However, approximately 85 percent of the Nile’s water originates in Ethiopia. Because Ethiopia is planning to dam part of the Nile River in order to generate electricity, Egypt is concerned that its access to the Nile’s waters will be adversely impacted. Although the disagreement has not yet turned into open conflict, it is clear that securing this important freshwater resource will define Ethiopian-Egyptian relations for many years in the future.

These conflicts over water resources are common throughout the world. Even in the United States, where freshwater resources are relatively abundant, different populations fight over the use of freshwater. One major debate that is currently being waged centers on the Colorado River system. This water system supplies water to Arizona, California, Nevada, Colorado, New Mexico, Utah, and Wyoming, but due to a drought that has reduced water flow in this river system, these seven states need to decide how to reduce water usage in order to preserve the river for all the other users. As populations grow, and as climate change alters precipitation patterns around the world, these conflicts over water will continue to occur, and with greater frequency, in the future.