A Map of Water on Earth: A Small Bubble to Protect

To mark World Oceans Day, we invite you to explore some figures that illustrate the importance of water on our planet. While the vastness of the oceans may seem infinite to us—as does the amount of water they contain—scientists at the U.S. Geological Survey (USGS) have created an illustration that truly brings home the relative scale of things.

Earth is also known as the Blue Planet because, with 71% of its surface covered by water, it appears as a blue marble in our solar system. But how much water is there on Earth?

The oceans contain approximately 96.5 % of all the water on Earth. But water isn’t just a liquid, as evidenced by aquifers, lakes, rivers, seas, and oceans… It’s also present in the air, in the form of water vapor, and as ice in glaciers (mountains and polar ice caps). Furthermore, water is found in every living organism. For example, our bodies are composed of 55 to 60 % of water!

The Water Cycle

Water does not stay in one place; it follows a cycle—some longer, some shorter—that causes each water molecule to travel a path from the oceans to the groundwater, passing through clouds, rivers, living organisms, and sometimes even our faucets and water bottles!
85 % of the water that evaporates comes from the oceans, which receive 77 % of precipitation.

The vast majority of the water on Earth is saltwater, found in the oceans. Unfortunately, this water is not directly drinkable, and humans must rely on freshwater to sustain themselves. Furthermore, our modern societies use enormous amounts of water to produce the (often unnecessary) goods we own.

Some Orders of Magnitude for Water on Earth

If all the water on Earth (oceans, polar ice caps and glaciers, lakes, rivers, groundwater, and water vapor) were concentrated into a sphere, that sphere would have a diameter of only 1,385 km. That is roughly the distance which separates Paris (France) from Algiers (Algeria)—so that’s relatively little! This sphere would have a volume of about 1,386 million cubic kilometers, which would contain approximately 1.38 × 10²⁴ liters of water—a staggering amount…

About 12,900 km³ Water—mainly in the form of water vapor—is suspended in the atmosphere. If all that water were to fall to Earth, our planet would be uniformly covered by a little more than 2.5 cm of water!

1,170 km every day³ Water evaporates or is released through transpiration (by animals and plants) into the atmosphere.

As for liquid freshwater, most of it is found in the soil and underground, far more than on the surface (lakes and rivers). Thus, more than 8,400,000 km³ Freshwater is stored in the continental crust, mostly within the first 800 meters below the Earth's surface. But of course, these are the glaciers and polar ice caps that contain the most freshwater : about 29,200,000 km³, or 68 % of the Earth's fresh water!

All the water on Earth in a bubble!

What if we were to depict all this water—which seems so abundant to us—as a sphere positioned next to Earth? That’s exactly what scientists at the USGS did, and the result is truly eye-opening!

This illustration shows spheres of various sizes relative to Earth. Their volume depends on the amount of water they contain.

The Largest Blue Sphere represents all the water on Earth: it isn't very much compared to the volume of our planet.

The intermediate-sized sphere represents the volume of liquid freshwater present in the ground: groundwater, swamps, aquifers, rivers, and underground lakes. Its volume is approximately 10,633,450 km³ and its diameter is only 272.8 km. It is indeed this sphere that represents the water directly available to all living beings on our planet—the water we drink and use every day for personal hygiene and our daily activities. It is important to note that 99% of this water remains unusable, buried deep underground.

Finally, the little blue marble The remaining portion, barely visible, represents the fresh water contained in all the lakes and rivers on our planet. Its volume is 93.113 km³ with a diameter of approximately 56.2 km. This refers specifically to surface water, which can be directly used by humans.

This illustration gives the term «blue planet» an entirely new meaning. It helps us realize just how limited—and therefore precious—immediately available water has become. It is up to all of us to preserve the quality of this water and to make it the best possible use.

Distribution of Water on Earth

A representation of all the water on Earth: a small, fragile sphere…
Howard Perlman, USGS / Jack Cook, Woods Hole Oceanographic Institution / Adam Nieman – License: DR

World Oceans Day 2012

It was in 1992, at the Earth Summit in Rio, that the Canadian government first raised the idea of a World Oceans Day. In 1998, UNESCO’s Intergovernmental Oceanographic Commission endorsed this international observance. Since 2003, this day has been coordinated by the Global Ocean Network and the American organization, The Ocean Project.

Thanks to our joint efforts, everyone’s participation, and the ever-growing engagement of all in observance of World Oceans Day, the United Nations General Assembly «designated June 8 as World Oceans Day, effective in 2009.».

Every year on June 8, aquariums, science centers, museums, organizations, and institutions dedicated to marine environmental education across all five continents celebrate World Oceans Day. This celebration of the ocean brings together more than 200 organizations in 50 countries. The program features activities, games, art workshops, lectures, films, and a festive day celebrating the ocean.

On June 8, 2012, the theme for World Oceans Day is: “Youth: The Wave of Change.”.

Finally, France celebrates World Oceans Day through the "Journées de la Mer.".