Global Desert Variations During 1985–2024 Associated With Effective Water Availability

Abstract Under accelerating climate change, variations in global desert area remain uncertain, with estimates differing by more than a factor of two. Here, we present the first 40‐year global mapping of desert area changes at 30 m resolution using Landsat imagery, achieving a classification accuracy of 92%. Our results show that global desert area exhibited a declining trend during 1985–2024, at a rate of −2.27 × 104 km2 yr−1, largely driven by decreases in Australia, East Asia, Central Asia, and South Africa. Desert area variations reflect the balance among water supply, soil moisture, and atmospheric demand. Our analysis indicates that episodic increases in water inputs, together with vegetation buffering, enhanced effective water availability, which coincided with global desert contraction. Human activities influence East Asian desert changes, whereas global desert changes reflect the combined effects of human activities and climatic factors. Climatic factors may play a primary role in driving desert variations.