Just as we are made of water, so is our world. Water covers about 71% of the Earth’s surface. There’s water in the clouds above us and there’s water hidden below the soil. The movement of moisture through our atmosphere determines our weather.

Water is among the most plentiful substances on Earth’s surface. From oceans, rivers, and lakes to the rain, snow, and hail that fall each day, Earth holds a nearly unimaginable amount of liquid water: about 327 quintillion gallons.

The adage that someone, somewhere, is always downstream from you is actually true. Everyone lives within a watershed — the surrounding area of land in which water collects and, ultimately, drains into a water source.

Water is often integral to culture. It affects how we interact with the environment around us, where we choose to live, and it is central to many festivals, prayers, and offerings. Water amazes and inspires us as artists, poets, and writers. And, we go to water to have fun! Think about how often we go to the water’s edge for recreation, rest, and relaxation.

The availability of fresh water is a basic need for communities. In the past, people settled in places with adequate water. Today, tens of millions of Americans continue to make their homes along the water’s edge.

Water is a shared resource. It flows between communities; the water used upstream is also used downstream. But it is not always shared equally. Water’s usefulness – and our unquestionable need for it – makes it a valuable commodity. Disputes over access and availability of water happen regularly, throughout the world, our country included. These disputes often lead to a difficult question for a community to answer: Who owns the water?

Humans not only drink water—we put it to work. We search for ways to control water and the energy it possesses. In 2010, Americans withdrew 355 billion gallons of water for use each day. Massive dams don’t just corral our drinking water. They can also generate power. Miles upon miles of canals and irrigation ditches water our crops. We use water to make goods like paper and computer chips, to keep lawns green, and for cooking and cleaning.

Increased global temperatures have a significant impact on the water cycle.  Climate change isn’t just about heat – some places will be colder, some hotter. But the overall changes in the climate will lead to new weather patterns and environmental impacts. Scientists predict rises in sea level, rises in sea surface temperatures, and significant loss of glaciers and ice sheets through melting.