We all learned that Earth’s surface is 70% water in elementary school, but how much water is actually on Earth and what does it look like in comparison to Earth’s size? This drawing from the USGS shows the surprising answer: a pretty small volume relative to the entire globe.
Global water volume visual representation by the USGS
There are three blue spheres in the image laid over top of the North American continent that show, in order of decreasing size, all the water in, on and above the Earth; liquid freshwater in groundwater and small water bodies; and all the freshwater in lakes and streams which is where most of our water used every day comes from.
This website also describes the Earth’s water distribution in tables and graphs. The less than 4% of Earth’s water that is fresh is vital to humans around the globe and most of it is contained in glaciers and ice as well as underground.
In class, we’ve learned how the Earth is a generally closed system (with regard to matter) and that every aspect is related and dependent. This website definitely shows an understandable breakdown of where our water comes from and why every part is important. It also gives a great spatial representation of the water on Earth in comparison to the size of the Earth. I was actually surprised by the visual!
Pretty interesting information when you take into account recent discoveries regarding how much untapped water the Earth may actually have: http://www.slate.com/articles/health_and_science/science/2014/03/water_in_earth_s_mantle_revealed_by_diamond_containing_the_mineral_ringwoodite.html?wpisrc=burger_bar
I am shocked to see that the “70% of Earth’s Water” only encompasses the western states of the United States! With supposed climate change on the rise, I wonder how rising sea levels would affect this representation if the USGS were to re-create it in five or ten years.
Like you said, we all learned that 70% of earth’s surface is water but I had no idea how little of it is useable to humans. This visual gives a different perspective which I had never considered before; in relation to the size of the earth and the actual amount of water. It definitely makes sense but I would not have thought of it without the drawing. This website and blog entry also do a good job of reminding us how
how limited our useable water resources really are. It is easy to forget that water is limited when we can turn on a faucet and water always comes out, but it is important to understand that though it seems like water is everywhere, it is an important and scarce resource that should not be wasted.