How Much Water Is There On Earth? – Ocean, Fresh Water & Drinkable Water

How Much Water Is There On Earth? – Ocean, Fresh Water & Drinkable Water

This is a guide about how much water there is on earth.

Below we’ve outlined some of the more important water quantity stats such as total water, fresh water and drinkable water numbers.

Note that these numbers are estimates, and are to be used as a general guide only.

 

Summary – How Much Water Is There On Earth?

The water on earth can be divided into:

  • Saltwater from the ocean – most of the world’s water is ocean salt water > around 97%
  • Freshwater – composed of under ground water (ground water), and above ground water (lakes, rivers, etc). There’s also the water locked up in ice and snow
  • Drinking water – water that is accessible and safe to drink, or able to be drunk once treated. Less than 1 percent of the world’s total freshwater supply is readily accessible from the various freshwater sources

 

How Much Total Water Is There In The World/On Earth?

  • About 71% of the world’s surface is covered by water

– USGS

 

If water quantities were to be described in spheres, the water distributions are as follows:

  • All water on earth (in the oceans, ice caps, lakes, rivers, groundwater, atmospheric water, and even the water in you, animals, and plants) – sphere volume of about 332,500,000 cubic miles (mi3) (1,386,000,000 cubic kilometers (km3)), and diameter is about 860 miles
  • All the world’s liquid fresh water (groundwater, lakes, swamp water, and rivers and DOES NOT include glaciers, snow and ice) – sphere volume comes to about 2,551,100 mi3 (10,633,450 km3), and diameter is about 169.5 miles (272.8 kilometers)
  • All of the world’s immediately accessible fresh water (in lakes and rivers) – sphere volume of 22,339 mi3 (93,113 km3), and diameter of 34.9 miles (56.2 kilometers).

– USGS

 

How Much Water Is In The Ocean?

  • Of the world’s surface water, about 96.5% is the ocean

– USGS

 

  • The average depth of the ocean is several thousand feet (about 1000 metres)

– HowStuffWorks

 

This gives us a rough idea of the volume of saltwater on earth.

 

How Much Fresh Water Is There On Earth?

  • About 2-3% percent of the planet’s water is fresh, but 1.6 percent (around 70%) of the planet’s fresh water is locked up in the polar ice caps, snowfields and glaciers
  • 0.36 percent of freshwater is found underground in aquifers and wells (also called groundwater)
  • Only about 0.036 percent of the planet’s total water supply is found in lakes and rivers 

– HowStuffWorks

 

The rest of the water on the planet is either floating in the air as clouds and water vapor, or is locked up in plants and animals and living things like humans

There’s also billions of gallons of drinkable water in bottles of water in shops on shelves around the world at any one time.

It’s important to note water is constantly moving on the Earth between the atmosphere, ocean, rivers and streams, snowpacks and ice sheets, and underground.

 

How Much Drinkable Water Is On Earth?

  • Less than 1 percent of the world’s total freshwater supply is readily accessible from the various freshwater sources

– Livescience

 

  • That’s still thousands of trillions of gallons, but it’s a very small amount compared to all the water available
  • As a % of the total amount of water available on earth that is ready and available to drink and use, that % number works out to be about 0.007 percent

– National Geographic

 

In other words, when you subtract all the salt water, water trapped in ice/snow and water not physically accessible, you have about 0.007% left to drink, and use for business and the community.

Much of that water we get from rivers and lakes.

Some of it is not going to be drinking quality – because of water pollution or contaminants for example.

There are no clear numbers at the moment of how much of the available/accessible freshwater is contaminated because that varies depending on where the water source is found, but it’s reasonable to say most of it is not contaminated.

The fresh water that isn’t contaminated can be run through water treatment plants and consumed as drinking water.

Some developing countries drink the water directly without water treatment.

 

Summary Of The World’s Water Sources (Salt, Fresh & Drinkable)

  • Of the world’s total water supply of about 332.5 million miof water, over 96 percent is saline. Of total freshwater, over 68 percent is locked up in ice and glaciers. Another 30 percent of freshwater is in the ground. Rivers are the source of most of the fresh surface water people use, but they only constitute about 300 mi3 (1,250 km3), about 1/10,000th of one percent of total water.

– USGS

 

You can look at a detailed table showing the estimate of global water distribution here at https://water.usgs.gov/edu/earthhowmuch.html , or at  https://water.usgs.gov/edu/gallery/global-water-volume.html 

 

Countries With The Most Freshwater

  • 6 countries (Brazil, Russia, Canada, Indonesia, China and Colombia) have 50 percent of the world’s freshwater reserves
  • One-third of the world’s population lives in “water-stressed” countries, defined as a country’s ratio of water consumption to water availability. Countries labeled as moderate to high stress consume 20 percent more water than their available supply.

– LiveScience

 

  • Due to geography, climate, engineering, regulation, and competition for resources, some regions seem relatively flush with freshwater, while others face drought and debilitating pollution.
  • In much of the developing world, clean water is either hard to come by or a commodity that requires laborious work or significant currency to obtain

– National Geographic

 

Will We Have Enough Water In The Future For Human Use?

Read this guide about the availability of freshwater for humans in the future.

 

Sources

1. https://water.usgs.gov/edu/earthhowmuch.html

2. https://science.howstuffworks.com/environmental/earth/geophysics/question157.htm

3. https://www.livescience.com/29673-how-much-water-on-earth.html

4. https://www.nationalgeographic.com/environment/freshwater/freshwater-crisis/

5. https://water.usgs.gov/edu/gallery/global-water-volume.html

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