Anthropogenic Climate change has driven over 5 million km2 of drylands towards desertification.

Drylands cover 41% of the earth’s land surface and include 45% of the world’s agricultural land. These regions are among the most vulnerable ecosystems to anthropogenic climate and land use change and are under threat of desertification. Understanding the roles of anthro- pogenic climate change, which includes the CO2 fertilization effect, and land use in driving desertification is essential for effective policy responses but remains poorly quantified with methodological differences resulting in large variations in attribution. Here, we perform the first observation-based attribution study of desertification that accounts for climate change, climate variability, CO2 fertilization as well as both the gradual and rapid ecosystem changes caused by land use. We found that, between 1982 and 2015, 6% of the world’s drylands underwent desertification driven by unsustainable land use practices compounded by anthropogenic climate change. Despite an average global greening, anthropogenic climate change has degraded 12.6% (5.43 million km2) of drylands, contributing to desertification and affecting 213 million people, 93% of who live in developing economies.

Figure 2. The contribution of anthropogenic climate change to vegetation change from 1982 to 2015. a The contribution of anthropogenic climate change (Climate Change + O2) component to the change in vegetation between 1982 and 2015 (ΔNDVI max). Non-dryland and hyper-arid regions are masked in dark gray and areas where the change is insignificant (αFDR = 0.10) or smaller than the error in the sensors (±0.001) are masked in white. b The mean area-weighted pixel effect size of the drivers of observed vegetation broken down by observed vegetation change direction. Positive indicates greening and negative is desertification. Error bars show the SD. c Frequency distribution function for the change in NDVImax (1982–2015) attributed to by anthropogenic climate change.