Nature often plays a mean trick on thirsty people. Unless you’re stranded in the desert, there’s often water, water everywhere, yet nary a drop to drink.
The problem isn’t ever the water itself, but the things suspended in it. The grit, organic matter and larger particles are just the start of the problem. In even the clearest running streams, disease-causing microbes, industrial compounds or naturally occurring arsenic can pose serious health risks.
Then there’s nature’s biggest barb—more than 97 percent of the water on Earth is too salty to drink. Whether it’s seawater or saline groundwater, imbibing salt causes the body to dehydrate and start shutting down.
Significantly less than one percent of the planet’s total supply of water is available fresh water for the 7.2 billion people living today, the animals and the wild and crop plants. While that supply stays about the same over time, our growing, urbanizing population and expanding industrial footprint means ever more demand. Societies around the world must deal with freshwater scarcity every day—the UN says some 1.2 billion people live where water is physically scarce.
Yet with saltwater all around, the answer to the problem has always seemed so close.