Environment desertification and nanotechnology

According to the estimates of the UN Environment Programme (United Nations Environment Programme - UNEP), one quarter of land on the planet is threatened by desertification. The lives of over a billion and half people in over 100 nations are put at risk by this phenomenon, since the crops become less productive.
Desertification is a gradual process by which a fertile and inhabited territory becomes an uninhabited and sterile region. This is an ancient disaster (nowadays desert regions were once rich in forests, pastures, cultivated fields), but only a few years ago it raises serious concerns, as the processes of desertification are developing on a global scale and their pace accelerated, making unusable every year worldwide approximately 60,000 km ² of land. In general the main cause of process of natural desertification is the natural fluctuations of climate conditions, but the decisive cause, nowadays, is undoubtedly the excessive human pressure on natural resources. Little rain, marked variability of rainfall from one year to another, persistent drought, deterioration of structures of soils, wind erosion, are all factors that predispose to desertification. It is therefore a process of "degradation of arable land in arid areas, semi-arid and dry sub-humid as a result of numerous factors, including climatic variations and human activities". Spots of degraded land may be hundreds of kilometres from the nearest desert. But they can expand and join with one another, creating conditions similar to those of a desert. And today we can partly control this phenomenon, thanks to research, in particular focused on nanotechnology. Let's see how.
The most precious asset we have is water.
It is estimated that the Earth contains about 1,400 million km3 of water, of which 35 million km3 (2.5 percent) are freshwater. The average annual rainfall on the ground amounted to 120,000 km3, of which approximately 75,000 km3 go back into the atmosphere by evaporation, the remaining 45000 km3 converge in lakes, ponds and flowing or infiltrate into the ground.
This fraction is what is commonly referred to as "water" world. All of these 45000 km3 part is not accessible because of the water is channelled into rivers inaccessible or dispersed during the seasonal floods. The quantity today taken for the various human activities amounted to 6,000 km3 of water resources. Since both the water that people are distributed in a non-uniform way, the situation is already critical in various countries and regions in the world. Increasingly large areas of the world are plagued by endemic shortages of fresh water and competition among various users is growing.
Current estimates showed that the human withdraw is about 3 600 km3 of fresh water, the equivalent of 580 m3 per year per capita.
Except for Europe and North America, agriculture is, by far, the largest consumer of water with about 70% of all levies in the world, while the civilian use (citizen) has about 10% and industry uses about 21%. With the increase in temperature the "useful" precipitation (not torrential) will decrease and we will have always less water in order to live, work and nourish. How will we do? Do not worry! Science and technology will solve this problem.
We have just have to use our head and begin to plan and design tens of thousands of “desalinators” that taking water from the sea and return it ready for all uses. People might say that desalination plants are too costly both in the realization that in management, but the nanotechnology will give us a hand, and what a hand!
For example, scientists are testing an advanced system for the desalination of water (no more than reverse osmosis as the existing facilities) that, by using a membrane of carbon nanotubes, will reduce by 80% the cost of desalination of seawater .
Not only that: membranes, which select the molecules according to size, thanks to electrostatic forces, could also separate various gases in the atmosphere and contribute to develop economic methods to seize the enormous quantity of carbon dioxide emitted, for example, by power plants, and prevent their release into the atmosphere.