I know this has nothing to do with IT, but what the hell. Wired.com ran an article which set me thinking. The simple facts are these:

• A company called Aqua Sciences has built a “water harvester” which pulls water out of the air. Technically, this is not too difficult to achieve except in areas of relatively low humidity—which is why I’m impressed. Aqua Sciences’ harvester can work in the middle of the Sahara desert. In fact it’ll work anywhere with humidity of 15% or greater (the Sahara has 25% humidity but almost no rain). It won’t work in high altitude deserts (like parts of the Atacama desert in Chile).
• It can produce about 500 gallons per day (which equates to a small stream). 500 gallons per day will supply 1000 people with drinking water at a price of somewhere between 25-30¢ per gallon. (Cheaper than bottled water by a long way).
• The US Army is buying some of these water harvesters (Aqua Science won a competitive tender) because it costs about $30 per gallon to supply US troops with water in arid areas of Iraq.
• The water harvester is built into a container that fits on the back of a truck and thus can be driven to where it is needed. It generates its own electric power (from a diesel generator) but it will work from mains electricity (or solar/wind power or whatever).

This interests me because the combination of population growth and global warming is quickly pushing the world towards a very severe water crisis. In 2000, scientists forecast that one in three people would face water shortages by 2025. They were wrong—by 19 years. That line was crossed this year.

Water shortage is defined as receiving less than 10 gallons per person per day—but the reality is that farming consumes far more than that per person, so the “big picture” is complicated. Feeding a person per day can consume hundreds of gallons of water (anything up to 800 gallons if you want to feed people beef). So the cities need much less water than the countryside.