Blue question mark

Do you think Earth will ever run out of water?
– Megan A., Grade 7

Volcanologist Jim Webster answers this question:

Hello Megan,

Your question is a good one. We often hear from the news media that there is not enough fresh, potable drinking water for all people on Earth, and that the number of people on Earth is increasing rapidly. So it might appear that our planet may one day run out of water. Fortunately, that is not the case.

Earth contains huge quantities of water in its oceans, lakes, rivers, the atmosphere, and believe it or not, in the rocks of the inner Earth. Over millions of years, much of this water is recycled between the inner Earth, the oceans and rivers, and the atmosphere. This cycling process means that freshwater is constantly made available to Earth's surface where we all live.

Volcanoe

Volcanoes release massive amounts of water from the inner Earth to the atmosphere.

Our planet is also very efficient at keeping this water. Water, as a vapor in our atmosphere, could potentially escape into space from Earth. But the water doesn't escape because certain regions of the atmosphere are extremely cold. (At an altitude of 15 kilometers, for example, the temperature of the atmosphere is as low as -60° Celsius!) At this frigid temperature, water forms solid crystals that fall back to Earth's surface.

mountain skyline with clouds

Water vapor in the air falls back to the surface as rain or snow.

zulu women carrying water buckets on their heads

Many people live faraway from freshwater sources. They need to carry their water home.

While our planet as a whole may never run out of water, it's important to remember that clean freshwater is not always available where and when humans need it. In fact, half of the world's freshwater can be found in only six countries. More than a billion people live without enough safe, clean water.

Also, every drop of water that we use continues through the water cycle. Stuff we put down the drain ends up in someone or something else's water. We can help protect the quality of our planet's freshwater by using it more wisely. Check out Be a Water Saver below for ideas.

You Can Make a Difference!

  • Be a Water Saver! You can help protect freshwater and the living things that depend on it.

 

 

Explore More: 

Jim Webster

Name:
Jim Webster

Job Title:
Curator, Department of Earth & Planetary Sciences

Known For:
Jim is a volcanologist. He wants to know why some volcanoes erupt explosively, and how he can help predict these eruptions in the future.

Cool Fact:
Jim travels around the world to collect volcanic rocks. In the lab, he analyzes these rocks and re-creates tiny volcanic eruptions!

Image Credits:
steaming volcano, courtesy USGS; rainstorm in Nevada, courtesy of NOAA; Zulu women carrying water buckets, Steve Slater via Flickr (CC BY 2.0); Jim Webster, © AMNH.