It is estimated that 98% of the Earth’s water is too salty for drinking or agriculture and one in 10 of the world’s population don’t have access to safe drinking water and almost two million people die from drinking unsafe water every year.
Of the 2% of water that is fresh water, two thirds is locked away in ice caps and glaciers while most of the rest is trapped in soil or underground aquifers which leaves a fraction available for us to use.
In just 15 years time, half the world's population could be living in areas where there isn't enough water to go round and already poor quality water supplies means more people are drinking from dirty sources, and water borne diseases such as typhoid are spreading.
The answer so far has been desalination which is turning sea water into fresh water but the process is high energy intensive and very expensive.
We need a way to make the process more efficient but technology formerly regarded as promising have been in lab development for decades and the by-product, brine, is a source of pollution to nearby water supplies.
Someone, somewhere had better get on it because with a warming globe and the devastation that is already causing, a lack of drinkable water will be the next major catastrophe us humans face.