In a landmark report that marks a turning point in our understanding of global aridity, UN scientists have revealed a stark reality: more than three-quarters of Earth’s land has become permanently drier over recent decades, fundamentally altering life on our planet. This unprecedented transformation threatens billions of people and could reshape entire ecosystems by the century’s end.
Published in UN Convention to Combat Desertification Proceedings | Estimated reading time: 6 minutes
The UN Convention to Combat Desertification (UNCCD) has documented that 77.6% of Earth’s land experienced increasing aridity between 1990-2020 compared to the previous three decades. During this period, drylands expanded by approximately 4.3 million square kilometers – an area nearly a third larger than India – and now cover 40.6% of all land on Earth, excluding Antarctica.
“Unlike droughts—temporary periods of low rainfall—aridity represents a permanent, unrelenting transformation,” explains Ibrahim Thiaw, UNCCD Executive Secretary. “Droughts end. When an area’s climate becomes drier, however, the ability to return to previous conditions is lost. The drier climates now affecting vast lands across the globe will not return to how they were and this change is redefining life on Earth.”
A Global Transformation
The crisis has hit some regions particularly hard. Almost all of Europe (95.9%) has experienced drying trends, alongside parts of the western United States, Brazil, eastern Asia, and central Africa. While less than a quarter of the planet’s land showed increased moisture, the overarching trend points toward an increasingly arid world.
For the 2.3 billion people – over 25% of the world’s population – living in expanding drylands, this new normal demands lasting, adaptive solutions. Under worst-case scenarios, this number could surge to 5 billion by 2100, creating unprecedented challenges for food security, water resources, and ecosystem stability.
Cascading Impacts
The effects of rising aridity extend far beyond simple dryness. The report reveals that aridity has become the world’s largest single driver of agricultural system degradation, affecting 40% of Earth’s arable lands. In Africa, rising aridity has been linked to a 12% decline in GDP between 1990-2015. The crisis has also been associated with increasing frequency and intensity of sand and dust storms in the Middle East, and is expected to amplify wildfire risks globally.
Key Terms
- Aridity
- A persistent, long-term climatic condition characterized by lack of moisture and where atmospheric evaporative demand significantly exceeds rainfall.
- Drylands
- Regions where water scarcity limits ecosystem productivity and human activities, now covering 40.6% of Earth’s land surface.
- Aridification
- The gradual process of a region becoming permanently drier, leading to lasting changes in ecosystem function and agricultural potential.
Test Your Knowledge
What percentage of Earth’s land experienced drier conditions in recent decades?
77.6% of Earth’s land became drier during the three decades leading up to 2020 compared to the previous 30-year period.
How does aridity differ from drought?
Unlike droughts, which are temporary periods of low rainfall, aridity represents a permanent transformation where an area’s climate becomes permanently drier with no ability to return to previous conditions.
What proportion of global arable lands are affected by aridity-driven degradation?
Aridity affects 40% of Earth’s arable lands, making it the world’s largest single driver of agricultural system degradation.
What percentage of global land could experience abrupt ecosystem transformations by 2100 due to rising aridity?
According to the report, 20% of global land could face abrupt ecosystem transformations by the end of the century due to increasing aridity.
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