Deforestation and desertification

Soil retrogression and degradation are two regressive evolution processes associated with the loss of equilibrium of a stable soil. Retrogression is primarily due to soil erosion and corresponds to a phenomenon where succession reverts the land to its natural physical state. Degradation is an evolution, different from natural evolution, related to the local climate and vegetation. It is due to the replacement of primary plant communities (known as climax vegetation) by the secondary communities.

Desertification is a type of land degradation in which a relatively dry area of land becomes increasingly arid, typically losing its bodies of water as well as vegetation and wildlife It is caused by a variety of factors, such as through climate change (particularly the current global warming) and through the overexploitation of soil through human activity

World annual deforestation is estimated as 13.7 million hectares a year, equal to the area of Greece. Only half of this area is compensated by new forests or forest growth. In addition to directly human-induced deforestation, the growing forests have also been affected by climate change, increasing risks of storms, and diseases. Kyoto protocol includes the agreement to prevent deforestation but not the actions to fulfill it

Deforestation, clearance, or clearing is the removal of a forest or stand of trees where the land is thereafter converted to a non-forest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use. The most concentrated deforestation occurs in tropical rainforests. About 30% of Earth's land surface is covered by forests.