Desertification and Droughts

Water is essential to life. Plants, animals and humans need it to survive. But even though the Earth surface is covered by 71% water and 29% land (Ref. 1), not every part of that land area receives enough water to sustain life. Approximately 33 % of Earth surface is desert, either hot or cold. Desert is defined as an area where rainfall is less than 25 mm a year (Ref. 2). There are four sub-categories of drylands, which are classified according to their aridity indices: dry and sub-humid; semi-arid; arid; and hyper-arid. Proportions of these dryland types taken from Ref. 3 are detailed in Table 1.

Type of Dryland Percentage of Earth’s Land Area Aridity Index
Dry and sub-humid 8,7 % 0,5 – 0,65
Semi-arid 15,2 % 0,2 – 0,5
Arid 10,6 % 0,05 – 0,2
Hiper-arid 6,6 % < 0,05
Total of drylands 41,3 % * From 0 to 0,65

Table 1:  Relative proportions of the four sub categories of dryland referred to the Earth’s land area. * Individual percentages are rounded so they do not sum up to the total amount

Drylands are home to more than 38 percent of the Earth’s population – that’s around 3 billion people. They also support around 44 percent of the world’s cultivated systems and half of its livestock. Drylands are particularly vulnerable with respect to climate change (Ref. 3). Climate warming is changing the weather patterns in such a way that generates increases in rainfall in some areas and reductions in others. Decreasing amounts of rain or the complete lack of it called drought can transform humid areas into semiarid areas or can convert a semiarid area into a desert.

For an extensive and detailed description of droughts and deserts, the reader is referred to references 4 to 7. For the increased intensity of droughts generated by the global mean temperature rise of the Earth, to reference 8 and for general knowledge of meteorology and an excellent description of thermal inversions, to the book in reference 9. The aim of this blog and web page is to propose a possible solution to the problems described. The proposal described here is a technique that could be used to generate rain in areas with low or very low rainfall. This technique could be a solution to the water scarcity problems in places like California, the Persian Gulf or the coastal zones of Peru, where atmospheric thermal inversions occur.


  1. “How Much Water is There on Earth?”, US Geological Service,
  2. “How much of the earth’s surface is desert?”,
  3. “Everything you need to know about drylands”, Landscape News, 25 March 2021
  4. “Understanding Droughts”, National Geographic.
  5. “Drought”, World Health Organization.
  6. “What is Drought?”, National Drought Mitigation Center, University of Nebraska-Lincoln, (2023)
  7. “Geomorphology of Desert Environments”, Anthony J. Parsons and Athol D. Abrams (eds.) 2nd Springer (2009)
  8. “Climate Change Science – A modern synthesis”, G. Thomas Farmer, John Cook. Volumes I & II, Springer (2013)
  9. “Meteorology Today: An Introduction to Weather, Climate, and the Environment” Chapter 6: Stability and Cloud Development, C. Donald Ahrens, 9th Ed., (2009) ISBN-13: 978-0-495-55573-5 
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