Hyper-arid zones should be considered a part of desertification, study says

By 23 junio, 2020Natural Sciences

Published in Nature Sustainability, the article warns that massive use of underground waters for agricultural purposes threatens to cause irreversible damage to these areas.Sahara

According to a study led by the Dryland Ecology and Global Change Lab at the University of Alicante (UA) and published in Nature Sustainability, hyper-arid zones should be considered as part of desertification. Massive use of underground waters for agricultural purposes threatens to cause irreversible damage to these areas and, as a result, many regions would lose this vital resource forever and experience desertification.

On the occasion of this year’s World Day to Combat Desertification and Drought, held on 17 June, the United Nations described desertification as “the degradation of land in arid, semi-arid and dry sub-humid areas. It is caused primarily by […] climatic variations.” Drylands are home to 2,100 million people, with 50% of global livestock and 44% of arable lands. It is estimated that between 10% and 20% of those 59 million km2 are severely degraded and that about 250 million people are directly affected. These figures are expected to get worse due to global warming and more intense and longer droughts associated with climate change.

However, conceptual doubts remain about desertification, which hinders the development of appropriate tools for detecting and solving this problem. The study led by Jaime Martínez Valderrama, a postdoctoral researcher at the UA Dryland Ecology and Global Change Lab, delves into one of these inconsistencies and highlights that hyper-arid zones, with a total area of 9.5 million km2, should be considered as part of desertification. He also stresses the need to design specific early warning indicators for these areas.

Hyper-arid zones coincide with the most extreme deserts on Earth, where human activity and desertification were supposed to be impossible. “In other words, who could imagine that deserts could experience desertification? Development of borehole drilling technology and availability of cheap energy have enabled large-scale underground water pumping. The growth of farming in unimaginable places (such as dairy farms in the Eastern Desert) has damaged these huge water reservoirs. As a consequence, hyper-arid regions now fall into the definition of desertification. Moreover, gradual climate aridification is turning drylands into hyper-arid zones. According to the current definition of desertification, these areas would not be part of the problem, even though they can experience desertification,” Martínez Valderrama explains.

“Based on these arguments, hyper-arid regions should be considered as part of desertification and specific tools should be designed for monitoring them, focusing on irrigated areas and piezometric levels of exploited underground water bodies,” UA Distinguished Researcher Fernando T. Maestre points out. He also directs the Dryland Ecology and Global Change Lab and is the principal investigator on the BIODESERT project, funded by the European Research Council, which made this study possible.

 

Reference

Martínez-Valderrama, J., Guirado, E., Maestre, F.T. 2020. “Desertifying deserts”. Nature Sustainability, doi: 10.1038/s41893-020-0561-2