Aridification

Aridification is the process of a region becoming increasingly arid, or dry. It refers to long term change, rather than seasonal variation. It is often measured as the reduction of average soil moisture content. It can be caused by reduced precipitation, increased evaporation, lowering of water tables, and changes in ground cover acting individually or in combination. Its major consequences include reduced agricultural production, soil degradation, ecosystem changes and decreased water catchment runoff. Some researchers have found that the Colorado River basin and other parts of western North America are currently undergoing aridification.