horizon - science prize - water?

Last night watched horrible horizon program detailing the woes of the world. we are short on food,water,energy, life saving antibiotics etc. They showed us the world's water is in short supply and only 2 percent is drinkable. So they showed desalination plants converting sea water to drinking water.

i keep thinking about the satellite views of Africa - mostly desert conditions. you have the Sahara which has very little life in it. Can't they build pipelines from the oceans and pump in sea water and flood the deserts. If you lived in that region I'd imagine a dip in a pool preferable to dying of heat exhaustion. some plants grow in sea water too. Water heats up and condenses in the atmosphere causing rain. leaving the salt behind. You would increase the surface area for condensation.
Deserts or a chance for something else?