Some Cool Facts About Water

In geology class, we just recently covered streams, in which the prof. included some interesting information about the “global hydrologic budget”. While I’ve long been acquainted with the “about 70% of the Earth is covered in water” bit, some of this really surprised me:

• Oceans and salt lakes account for 97.41% of the Earth’s water.
• Ice and snow takes up another 1.984%.
• Groundwater is the small guy at the party, at a mere 0.592%.

So where do lakes and rivers, along with the atmospheric water, rank? Not very high, that’s for sure. Lakes and rivers account for 0.0071% of the water in the Earth’s system; atmospheric water only accounts for 0.001%.

To put things into a little perspective, the prof. presented us with an analogy. Say you take all of the water in the Earth’s system, and shrink it down to 26 gallons^[1]. Freshwater - all of the fresh water - would add up to about 0.7 gallons, 2.59% of the 26 gallons. However, readily available freshwater would come in at a miniscule half teaspoon, or 0.003%.

That is still, however, a lot of water. The total amount of water floating around (awful pun!) on Earth totals 1,357,870,000 cubic kilometers. Try wrapping your head around that…

And now, I’m dying for a glass of water. Off to the tap!

1. There’s a reason the analogy uses the, admittedly, strange value of 26 gallons. 26 gallons is equivalent to the nice, round 100 liters. However, being an American, I use the highly illogical ounce, pint, quart, gallon, etc. system. My apologies! [↩]