Water by mass
The Earth consist of 30% Land and 70% water by mass, but out of the 70% water, only 3% are freshwater, of which only around 30% are available to us to extract for use. To do a simple math, that would be 0.9% of total mass of water on Earth available for use.
Distribution of the world’s water. Source: Courtesy “Earth Update” CD-ROM, Rice University and the Houston Museum of Natural Science
Top Sources of water consumption
Shiklomanov (1993); UN FAO Aquastat database
Food
Sure, the total mass of water on Earth is massive, and 0.9% of that is still significant, but humans are not the single consumer of water in the world. To produce 1kg of beef, it requires 13000L of water, and 1kg or rice requires 1400L of water1. Imagine the multitude of food that we consume every day and how much water is required to produce them. To top that off, human population is at its historical peak right now of about 7.26 billion (14 Sept 2014).
Source: Institution of Mechanical Engineers (2013)
Energy production
To be reading this, you must be running some sort of device on electricity. As we advance along the technology age, we find that in order to function properly, we need electricity. To power-up the lives of 7.28 billion people, we need 15 terawatts (15 million megawatts) of power every day3. A typical 500-megawatt coal-fired or nuclear power plant, for example, might withdraw about 400 million gallons of water a day from local lakes, rivers, or aquifers, and lose several million gallons of that water to evaporation4. Multiply that by 30,000 and you will get a simplified estimate of how much water is neededto generate electricity in the world if we don’t invest in alternative energy sources.
So there you have it, we are left with a mere 11% of accessible freshwater for consumption, which is not enough for everyone. In order to provide enough freshwater for everyone, there has to be desalination plants and water treatment plants set up to produce more freshwater. So what happens if a country has neither lakes nor rivers that provide naturally filtered fresh water? Read about Singapore’s unique case study next.