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.
It’s the near future, at night. A New Panamax cargo ship cuts through the North Atlantic and begins its traverse of the Sargasso Sea. The ship is in its regular lane on a journey from Rotterdam to the port of Los Angeles via the newly expanded locks of the Panama Canal.
Moonlight from the north illuminates the topmost layers of some 12,000 20-foot containers stacked on the ship. It’s calm seas, but unseen in the total darkness to the ship’s southwest is a rapidly developing hurricane that spun off from the west coast of Africa as a tropical wave just days before.
If there were windows on the bridge, perhaps the third mate would be peering into the night to catch a glimpse of the weather system’s outline. If there were a bridge, perhaps the second mate would be pouring over real-time weather data and navigation equipment. If there were a captain, perhaps he’d be weighing the decision to pick up speed to outrun the storm or slow down to let it pass.
But this is the new class of autonomous ships plying the world’s oceans, and none of these people or objects is aboard. A pilot monitors the ship remotely from Rotterdam and no crew are in danger. Automated decision systems informed by streams of navigation and weather data alter speed to let the main body of the hurricane pass safely in front of the ship. Neither life nor property is put at risk, and the system plugs in new operating commands to pick up speed and arrive at port on time.
When the sun goes down on almost 1.3 billion people around the world, the only respite from the darkness is fire. These are the people who have no access to electricity. If children want to study, or adults want to remain productive, or families want to sit and talk, most must do it by light of a flame.
But light sources like wood, candles, or hydrocarbons like kerosene oil, which was burnt at the rate of 38.7 million gallons a day in 2010, are far from the best solution. Combustion is dirty, releases toxic chemicals and can be expensive.
“A fifth of the world’s population earns on the order of $1 per day and lacks access to grid electricity,” wrote Evan Mills, a Lawrence Berkeley National Lab staff scientist, in the 2012 technical report Health Impacts of Fuel-Based Lighting. “They pay a far higher proportion of their income for illumination than those in wealthy countries, obtaining light with fuel-based sources, primarily kerosene lanterns. The same population experiences adverse health and safety risks from these same lighting fuels.”