UN Report on Global Aridity and Desertification

Populations Living in Drylands on the Rise

World Day to Combat Desertification and Drought—held each year on June 17—was designated in 1994 by the UN. The day “raises awareness and promotes solutions to desertification, land degradation and drought.” Desertification, or land degradation in dry areas often leading to deserts, has potential impacts on biodiversity, human poverty, reduction of soil fertility and agricultural production, and increase in water scarcity. It can even contribute to climate change, as desertification reduces the soil’s capacity to store carbon. Below are key findings on desertification issues from the 2024 report released at 16th Session of the Conference of the Parties of the United Nations Convention to Combat Desertification (or UNCCD COP16) in December 2024.

1. The Earth’s land area percentage of drylands increased from 37.5% in 1961–1990 to 40.6% in 1991–2020, or by 4.3 million square kilometers (1.6 million square miles). This is comparable to a land mass the size of Egypt, Libya, and Chad combined.

2. Based on six aridity index classes of global lands, 55.1% was “humid”; 14.3% was “semi-arid”; 10.5% was “arid”; 9.1% was “hyper arid” (such as the Sahara); 6.7% was “dry subhumid”; and 4.3% was “cold” (such as Greenland).

3. Aridity is considered the world’s largest single driver behind the degradation of agricultural systems, affecting 40% of Earth’s arable lands, or about 5.7 million square kilometers.

4. The lowest percentage of drylands is in Europe, with 12.1% in 1991–2020. But Europe had the highest increase—4.8%—in drylands from in 1961–1990. Europe also had the least percentage of human population living in drylands in 2020 at 10.7%, but this was an 87% increase from 5.7% in 1990.

5. Africa has the highest percentage of drylands at 70.5% in 1991–2020. Almost half of its population—49.6%—lived in drylands in 2020, the highest among all regions.

6. The number of people living in drylands was about 2.3 billion in 2020, almost double from 1.2 billion in 1990. In terms of global population, this was an increase from 22.5% in 1990 to 30.9% in 2020.

7. Based on worst-case climate models, as many as 5 billion people could be living in drylands by 2100.

8. Antarctica is also a desert, but as an ice-covered polar area, it is excluded from the UN’s drylands analysis.  

Sources:

• United Nations World Day to Combat Desertification and DroughtUnited Nations Desertification and Drought Day 2025IPCC Special Report on Climate Change and Land - Chapter 3: Desertification

• UNCCD COP16 Report: "The Global Threat of Drying Lands: Regional and global aridity trends and future projections"Worldometer - Largest Countries in the World (by area)NASA - Frequently Asked Questions About Antarctica