In recent years, the problem of desertification by unnatural causes, mainly attributable to human activities, directly affects approximately six hundred million people.
Among the natural causes that lead to desertification, one can consider the cyclical nature of the ice ages, resulting in global warming that occurs in interglacial periods.
In this regard, there are theories that blame the general desertification living Earth to this warming, as some scientists say could be living the high point of this interglacial period, that argument is countered by another important sector of the scientific community.
They are also natural causes the warming of the atmosphere caused by extraordinary phenomena such as giant eruptions of a volcano or the impact of large meteorites on Earth's crust.
In addition, the abundance of poorly consolidated rocks, prone to further erosion, contributes to the process of desertification.
With regard to unnatural causes, include EU agriculture and industry as the most human activities have affected the soils of the earth's surface. Among the first is the search for arable land and its subsequent exploitation, resulting in the removal of existing vegetation and, ultimately, sterility of the soil.
The loss of the vegetation and bare soil exposure decreased the water absorption capacity, due to increased runoff, and increase the surface albedo (reflection of sunlight from the ground in all directions).
The increase in albedo negative effect on cloud formation, decreasing therefore rainfall. The clearing of forests for soil cultivation, widely practiced throughout the world, is rapidly decreasing the amount and area of woodland, especially in the tropics, and is changing the surface characteristics of large areas of the Earth .
Another practice that entails the destruction of the vegetation is overgrazing. It is normal in these activities deforestation and woodland arson in order to extend the grazing areas. Also the introduction of grazing causes massive loss of vegetation, because they prevent natural regeneration of plant species.
Industrial activities make up another large group of human practices provoking global desertification of the planet. They affect preferably on the essential elements of climate, unlike the previous ones, whose effects are felt mainly in soils.
There are two main consequences arising from the industrial processes involved in the general erosion of the planet, acid rain and the greenhouse effect.
Acid rain has become more industrialized areas of the world, the main source of pollution, deforestation can produce large masses of vegetation.
In Germany, for example, acid rain is responsible for the loss of half the forests in the most industrialized areas. Moreover, the greenhouse effect has been shown in recent years as the primary cause of global warming, and therefore processes desertification that this entails.
The greenhouse effect arises from the excessive emission of certain types of gases, especially CO2, which are suspended in the atmosphere, forming a layer that allows input of radiation from outer space but not out, because when it hits the surface ground and re-projecting outwardly are unable to penetrate the layer of gas, thus producing a gradual warming of the atmosphere.
CO2 emissions may occur naturally, but in recent years the increase of CO2 in the atmosphere has been so high that is associated with modern industrial processes and excessive burning of fossil fuels.
Scientists have calculated that the increase of CO2 in the atmosphere has been 15% during this century, and today the rate of increase is 0, 33% annually. With these data, concludes that the atmosphere is exposed to excessive heat, which is causing climate change that favors the processes of desertification of large areas of Earth.
Of course, the most likely to be affected are those with a relative degree of aridity or semi-arid.
The process of desertification affected areas of all continents: North and South Mediterranean basin, sub-Saharan Africa, Middle East, Australia, etc.. It is estimated that the extent of land affected by this problem is over 34,000,000 km2.
To tackle it is necessary from all over the world in the implementation of conservation policies, whose implementation, however, is hampered by the current dynamics of the global economy.
Control measures such as emissions of gases into the atmosphere, the reforestation programs of forest or agricultural development policies that take into account the regeneration of the land, are essential to prevent further spread of desertification by the Earth.
However, the results of these are unlikely to be substantial short-term.
