Stone, sand and salt deserts – almost one third of the earth’s surface is sparse, barren land – an area that is ever growing. The majority of it has developed over thousands of years, like here – the rock formations of the desert in the giant mountains of Hoggar in Algeria. But today the expansion of the desert is manmade.

Desertification refers to this eroded area of land. It applies particularly to regions of land that are already dried out, like in parts of Africa, America or Asia. This wheat field in Texas (USA) did not withstand the severe drought that occurred in summer 2011.

Around 70,000 km2 of desert is created every year – an area that is around the size of Ireland. As well as climate change, people are really to blame for the expanding desert. People working on the land, like here in Brazil, in Latin America, have to adapt to the changing climate to grow sufficient crops in the future.

Too many animals are drying out the land. They eat the last small plants, so that the earth is no longer protected from wind and water. When there is a drought, it leads quickly to desertification: the soil becomes looser and weak and is easily worn down.

The already widespread drought makes it difficult for farmers to grow crops – like here in a cornfield in Mexico. And it doesn’t help that the fields are often not looked after. After the harvest, they are not given the recovery time they need before the next crops are planted. The result: the soil loses nutrients and fewer plants grow – it also leads to erosion.

The number of trees is also greatly decreasing. To find fuel, or timber, or to make way for farmland, industrial areas, or for new housing, people cut down trees and destroy forests. Trees prevent erosion of topsoil by wind and water. But as they are chopped down, the ground is left vulnerable – it becomes desolate and dry.

The population is growing – and so water consumption is increasing. Over the past 50 years, it had doubled worldwide. It is particularly as a result of intensive agriculture – irrigation of vegetable fields has caused water supplies to shrink dramatically.

Once desertification has started, it sparks a chain reaction: Because plant growth is destroyed, the water evaporates and the soil dries out. It becomes saline and as tough as a tank, like here in India. It is difficult to save such barren soil.

Desertification not only leads to the destruction of the ecosystem, the consequences go much further. It can lead to the extinction of species, to poverty, hunger and a lack of water – a consequence that brings with it drought. In West Africa countries, like here in Burkina Faso, the growth of the desert has a devastating impact on the people. It’s a vicious circle.

Reversal of desertification is possible, but it’s also expensive. So reforestation, instead, is seen as a way to regain lost vegetation. Here new trees are being planted to protect the eroded mountains in the Dominican Republic. So far, however, the global success of such projects has been moderate.

The UN Convention to Combat Desertification came into force in 1996. Since then, the objective has been to push back dry, barren land and stop the spread of deserts. A day dedicated to the fight against desertification takes place on June 17 every year.