drought

A long period of time without precipitation or with a marked deficit thereof, causing a serious hydrological imbalance. Droughts are characterized by the persistence of an anomalously dry type of weather, during which precipitation values remain below average. The initial cause of any drought is the scarcity of precipitation (meteorological drought), which brings with it a soil moisture deficit (agricultural drought), which negatively affects crop production and alters the various ecosystems. This second phase is followed by a third and final one, in which the water resources needed to meet existing demand become insufficient (hydrological drought). There is no single, universal definition of drought that precisely fixes its onset and end, as well as its intensity, since depending on the location (different climatic realities) and the uses given to water, its conception and perception differ. The scientific literature includes more than a hundred different definitions of drought, which gives an idea of the difficulty of characterizing it.