Dryland types found in rangelands globally

Drylands are found mainly in tropical and temperate latitudes and account for approximately 41% (or approximately 62,000,000 km2) of the global terrestrial area. They can be classified into four types encompassing a variety of ecosystems: arid (P/PET Precipitation/Potential evapotranspiration 0.05-0.20), semi-arid (P/PET 0.20-0.50), dry subhumid (P/PET 0.50-0.65), and other including hyper-arid lands. This map shows the coverage of dryland types in rangelands only.

Key figures

1. Using the classification of rangelands outlined in Map 1, all drylands are found in rangeland areas. 78% of rangelands (approximately 62,000,000 km2) are classified as drylands. Only around 22% or approximately 18,000,000 km2 of rangelands are not classified as drylands. 

2. The largest area of drylands are classified as semiarid with P/PET (Precipitation/Potential evapotranspiration) 0.20-0.50: these semiarid areas cover approximately 20,000,000 km2 of the earth’s land surface.

Dryland types found in rangelands globally



Dryland types

Area km2


Arid: P/PET 0.05 - 0.20



Semiarid: P/PET 0.20 - 0.50



Dry sub humid: P/PET 0.50 - 0.65



Additional areas included in CBD definition






Source1: Terrestrial ecoregions of the world. Downloaded in 2021 from: https://globil-panda.opendata.arcgis.com/datasets/wwf-priority-35-ecoregions?geometry=-172.266%2C-86.819%2C172.266%2C89.233.Original source: Olson, D. M., Dinerstein, E., Wikramanayake, E. D., Burgess, N. D., Powell, G. V. N., Underwood, E. C., D'Amico, J. A., Itoua, I., Strand, H. E., Morrison, J. C., Loucks, C. J., Allnutt, T. F., Ricketts, T. H., Kura, Y., Lamoreux, J. F., Wettengel, W. W., Hedao, P., Kassem, K. R. 2001. Terrestrial ecoregions of the world: a new map of life on Earth. Bioscience 51(11):933-938

Source 2: UNEP-WCMC (2007) A spatial analysis approach to the global delineation of dryland areas of relevance to the CBD Programme of Work on Dry and Subhumid Lands. Dataset based on spatial analysis between WWF terrestrial ecoregions (WWF-US, 2004) and aridity zones (CRU/UEA; UNEPGRID, 1991). Dataset checked and refined to remove many gaps, overlaps and slivers (July 2014).Downloaded in 2019 from: https://www.unep-wcmc.org/resources-and-data/world-dryland-areas-according-to-unccd-and-cbd-definitions