Origin and Evolution of the Desert

Desert landscapes are the least understood among terrain types of the Earth. The dearth of basic information on arid landforms has resulted in the misconception that the desert is man-made and that, therefore, we can 'fix it'. Scientific evidence indicates that deserts are part of the natural features of both Earth and Mars. They form as a result of the lack or scarcity of rain, which may be cyclical. The basic layout of today's arid terrain appears to have formed during humid periods in the geological past. Understanding of such features and those caused by wind erosion and deposition is essential to the development of deserts and semiarid lands for the benefit of mankind. Images obtained by spacecraft provide a new tool that is very useful in this regard, particularly in the location of groundwater resources to be used at times of cyclical droughts.