Roughly 6% to 9% of the world’s drylands have experienced desertification since the early 1980s, depending on the study and time window. That translates to somewhere between 2.7 million and 4.1 million square kilometers of land losing its vegetation and productivity. To put that in perspective, drylands themselves cover about 41% to 46% of all land on Earth, so even a single-digit percentage of degradation represents an enormous area, and the process is accelerating in some regions while slowing in others.
The Numbers Behind Global Desertification
Desertification isn’t the spread of sand dunes across a landscape. It’s the sustained loss of vegetation and soil productivity in dryland regions, areas that are already semi-arid or arid but still support life. When researchers measure it, they track changes in plant growth over time using satellite imagery.
A 2020 study in Nature Communications found that between 1982 and 2015, about 6% of the world’s 44.5 million square kilometers of drylands experienced significant desertification, totaling roughly 2.7 million square kilometers. That’s an area larger than Algeria. The IPCC’s Special Report on Climate Change and Land puts the figure higher: about 9.2% of drylands showed declining vegetation productivity between the 1980s and 2000s. The difference comes down to methodology and time periods, but both estimates point to the same reality. Millions of square kilometers of once-productive land are losing their capacity to support crops, livestock, and ecosystems.
Not all the news is bad within those same drylands. The Nature Communications study found that 41% of dryland areas actually showed significant greening over the same period, while 53% had no significant change. Desertification is not a uniform global march. It’s patchy, with some areas recovering even as others collapse.
How Fast Land Is Being Lost
The UN Convention to Combat Desertification (UNCCD) estimates that at least 100 million hectares of healthy land are lost globally every year. That figure covers all forms of land degradation, not just desertification in drylands, but it gives a sense of the annual pace. One hundred million hectares is roughly the size of Egypt disappearing from productive use each year.
In the Sahara specifically, the pattern has shifted over time. Between 1950 and 1984, the desert expanded at roughly 35,000 square kilometers per year, with its southern boundary pushing about 170 kilometers into the Sahel. That expansion totaled around 1.2 million square kilometers over those three decades, an area about twice the size of France. After 1984, rainfall patterns partially recovered, and the Sahara actually shrank by about 12,000 square kilometers per year through 2015. Over the full 1950 to 2015 period, the net expansion averaged around 11,000 square kilometers per year, representing an overall 8% increase in the desert’s size.
What Drives Desertification
Two forces work together: human land use and climate change. Overgrazing strips vegetation faster than it can regrow. Clearing trees for agriculture removes root systems that hold soil together. Unsustainable irrigation can draw down water tables and leave salt deposits that poison the ground. These pressures are especially intense in regions where growing populations depend directly on the land for food and fuel.
Climate change compounds the damage. Rising temperatures increase evaporation, drying out soils that might otherwise recover between growing seasons. Shifting rainfall patterns can turn a manageable dry spell into a multi-year drought. The severe West African drought of the 1970s and 1980s is a textbook example: reduced rainfall combined with heavy land use caused rapid desert expansion across the Sahel, devastating food and water security for millions.
Neither factor acts alone. Research consistently shows that desertification is worst where unsustainable land practices meet a drying climate. Remove either pressure, and the land often has a fighting chance of recovering on its own.
Who Is Affected
About 3 billion people live in the world’s drylands, roughly 38% of the global population. Of those, the IPCC estimates that around 500 million people were living in areas that experienced significant productivity loss between the 1980s and 2000s. The United Nations puts the broader threat even higher, estimating that over 1 billion people in roughly 100 countries have livelihoods threatened by desertification, with nearly 1 billion of the poorest and most marginalized people living in the most vulnerable areas.
The economic toll is staggering. The Economics of Land Degradation Initiative estimates that the global loss of ecosystem services from degraded land costs between 6.3 and 10.6 trillion dollars per year. That includes lost agricultural productivity, reduced water filtration, diminished biodiversity, and the downstream costs of displacement and conflict that follow when land can no longer support communities. Water scarcity, which desertification intensifies, already affects between 1 and 2 billion people, most of them in drylands.
Restoration Efforts and Their Limits
Global commitments aim to restore 1 billion hectares of degraded land by 2030, a target set through the UNCCD and reinforced by the UN Decade on Ecosystem Restoration. Some countries have made measurable progress. Botswana has reported rehabilitating 1.42 million hectares through targeted remediation. Uzbekistan planted drought-resistant trees across 1.6 million hectares of the dried-out Aral Sea bed between 2018 and 2022 to stop salt and dust storms.
These are real successes, but they’re small against the scale of the problem. With 100 million hectares degrading each year, restoration efforts need to dramatically outpace current losses just to hold steady. As of 2022, only 126 countries had submitted national reports to the UNCCD, and the data remains incomplete. The gap between what’s being lost and what’s being restored is still wide, and the 2030 target will require a major acceleration in both funding and action to come within reach.