This refers to the spread of deserts. Deserts surfaces cover nearly 33% of the Earth. They are characterized by very little rainfall high temperatures, low humidity, and scanty vegetation.

Desertification also refers to a decline in the biological or economic productivity of the soil in arid and semiarid areas resulting from various factors, including human activities and variations in climate.

Desertification refers to the formation and expansion of degraded soil, not to the advancing movement of the current deserts.

Desertification is found on every continent except Antarctica, but international attention has focused mostly on Africa, particularly the region known as the Sahel, the region of northern Africa immediately to the south of the Sahara desert.

Desertification has been recognized as a problem since the Dust Bowl of the 1930s in the Midwestern United States, but it only became an international issue during the Great Drought in the Sahel between 1968 and 1973.