Aridity Site

: Extreme dryness with almost no vegetation; covers 4.2% of global land.

Aridity is a permanent climatic feature of regions where the long-term average water supply (precipitation) is significantly lower than the atmospheric demand for water (potential evapotranspiration). Unlike drought, which is a temporary and anomalous period of moisture deficit, aridity is a chronic state of water scarcity that defines the very character of an ecosystem. It is primarily measured using the , calculated as the ratio of annual precipitation to potential evapotranspiration. Classification of Arid Environments aridity

Growing aridity poses threats to global land surface - Nature : Extreme dryness with almost no vegetation; covers 4

: Transition zones with enough moisture for grass and some crops; covers 12.2% of global land. Drivers and Ecological Impact It is primarily measured using the , calculated

Regions are categorized based on their AI values to determine the severity of water limitation. According to the Food and Agriculture Organization (FAO) , drylands cover roughly 41% of the Earth's land surface and are classified into three primary zones:

: Limited rainfall and specialized vegetation; covers 14.6% of global land.