Cheaper desalination
Current thinking
THERE is a lot of water on Earth, but more than 97% of it is salty and over half of the remainder is frozen at the poles or in glaciers. Meanwhile, around a fifth of the world's population suffers from a shortage of drinking water and that fraction is expected to grow. One answer is desalination—but it is an expensive answer because it requires a lot of energy. Now, though, a pair of Canadian engineers have come up with an ingenious way of using the heat of the sun to drive the process. Such heat, in many places that have a shortage of fresh water, is one thing that is in abundant supply.This article appeared in the Science & technology section of the print edition under the headline “Current thinking”From the October 31st 2009 editionDiscover stories from this section and more in the list of contentsExplore the edition