It is using the simple action of condensation from moist ground with a membrane barrier above ground to create the condensation. You have all seen polythene lying on the lawn with water droplets forming on the underside. This moisture has been drawn from the ground due to the effect of the daytime heat.

Imagine this condensation system on a monumental scale. Look at the diagram (left) and you will see the idea situated in our coastal desert regions of the planet.

The sea water would be let into subterranean water tables which would be parched from the lack of rains. Once the land is fully saturated the membrane would condensate the moisture and water would gather on the underside of the huge membranes.

The membranes can be constructed in such a way that the droplets form and run off to be used as irrigation or drinking water. If drinking water was the main product it would be best to treat the waste and then re-use that water for the irrigation of trees and shrubs and other water retaining plants. This would stop the water getting back into the hydro-cycle and counteracting the intention of keeping sea levels stable.

Another big advantage of this system is that massive amounts of salt would be produced. This would bring two major benefits. Firstly, salt has reflective qualities. If large enough areas of desert land are coated with this by-product of desalinisation, it would cause some of the sun's light to be reflected back into space, much like the snow and ice caps do in the polar regions. This would contribute to lowering global temperatures.

Secondly, the excess salt can also be used to re-salinate the North Atlantic. With the Greenland ice sheet melting there is far too much fresh water getting into the North Atlantic. This can effect how the Gulf Stream or Atlantic conveyor works. If it causes the Gulf Stream to stop, the results would be catastrophic.

Northern Europe would suffer from severe winters and the farming and food production would be immensely affected. This could turn into a huge emigration, causing problems all around the world. The economic knock on effect would be global and world economies would tumble due to the problem.

So a simple idea using condensation would solve a whole load of possible problems.

• Major cities around the world would be safe from flooding
• Global economies would be safeguarded
• Drought could be solved and also solving starvation in the Horn of Africa
• Vast amounts of oxygenating vegetation could be grown
• A boost for construction, drilling and shipping companies

The aims of this idea could also be achieved using wind or solar powered sand filters.