Global share of Earth's water resources

Over 97 percent of the water resources on Earth is found in the ocean and other saline water sources; thus, only about 2.5 percent of the water on Earth is freshwater. As the main constituent of Earth's hydrosphere, water is vital for all life forms.

Freshwater resources

In fact, most of our freshwater is essentially inaccessible, trapped in glaciers or underground as groundwater. About 1.2 percent of this freshwater is considered surface water, which is essential to support life’s needs. However, almost 70 percent of this surface water is found as ground ice and permafrost.

Lakes and rivers

Lakes are an easily accessible water resource. They are generally formed when runoff from rain and snow accumulates or when groundwater rises to the surface. Lakes act as a valuable source of water for human needs and are also used for recreation. Rivers make up an even smaller percentage of our freshwater resources, however, they are one of the most important sources of water for humans as well as an important ecosystem for wildlife. River systems serve as a network for transportation, power generation, recreation, and water supply. Rivers form where water runs downhill. The Nile River is one of the longest rivers on Earth, running over 6,670 kilometers through several countries in Africa.