Causes of Desertification

Desertification emerges from a combination of natural pressures and human-driven land use. Climatic factors—high temperatures, irregular rainfall, prolonged droughts, and high evaporation—stress already fragile dryland ecosystems.

Human activities often push these stressed landscapes past a tipping point. Key drivers include:

• Overgrazing: Livestock remove vegetation faster than it can regrow, leaving bare soil exposed to wind and water erosion.
• Deforestation: Clearing trees for fuelwood, pasture, or crops removes roots that stabilize soil and disrupts local water cycles.
• Poor irrigation practices: Over-irrigation and inadequate drainage cause waterlogging and salinization, which reduce soil fertility.
• Unsustainable farming: Continuous cropping, deep tillage, and lack of ground cover accelerate topsoil loss.
• Soil compaction and pollution: Heavy machinery and excessive agrochemicals degrade soil structure and biology.

When these pressures act together, vegetation thins, soil structure collapses, and the land’s ability to hold moisture and support life declines—creating the conditions associated with desertification.

The Role of Climate Change in Desertification

Climate change amplifies existing land degradation and increases the risk of desertification. Rising temperatures boost evaporation and dry out soils. In many drylands, rainfall is becoming more erratic—arriving in shorter, more intense bursts or failing altogether.

Increased drought frequency and severity reduce plant cover, leaving soil unprotected. Heat and water stress also shift plant communities, making ecosystems more vulnerable to pests, fires, and invasive species.

Desertification and climate change reinforce each other:

• Loss of vegetation reduces carbon sequestration.
• Eroded, bare soils reflect more heat and may release stored carbon and nitrous oxide.
• Degraded land supports fewer trees and shrubs, weakening local cooling and rainfall feedbacks.

This feedback loop shows why restoring degraded land is a climate solution as well as a local livelihood and biodiversity strategy.

Desert Expansion and Aridification

Desertification is closely linked to both desert expansion and aridification.

Desert expansion refers to deserts spreading into formerly productive lands. This can happen when vegetation is removed and soil is left exposed, allowing desert wind and sand to move further into croplands, rangelands, and settlements.

Aridification describes the long-term drying of a region due to shifting climate patterns—less rainfall, higher temperatures, and increased evaporation. In areas with already fragile soils and high population pressure, this shift quickly translates into land degradation and declining yields.

Where aridification meets unsustainable land use—deforestation, intensive tillage, overgrazing, and poor water management—desertification accelerates, and recovery becomes more difficult and costly.

Soil Erosion, Deforestation, and Overgrazing

Three interacting processes sit at the heart of many desertification hotspots:

• Soil erosion: Wind and water strip away the nutrient-rich topsoil once vegetation is removed, drastically reducing productivity.
• Deforestation: Cutting trees eliminates canopy cover, root networks, and organic matter inputs, leaving soil exposed and drier.
• Overgrazing: Excess livestock pressure removes grasses and shrubs, compacts soil, and blocks natural regeneration.

Together, these processes create a downward spiral: less vegetation leads to more erosion, which leads to poorer soils, which then support even less vegetation—a classic land degradation feedback.

Water Scarcity and Soil Salinization

As desertification progresses, water scarcity and soil salinization often intensify. Degraded soils hold less water, surface flows increase, and groundwater recharge declines. Combined with lower rainfall and higher evaporation, communities experience more frequent water shortages.

Soil salinization occurs when:

• Salty irrigation water is applied repeatedly without adequate leaching or drainage.
• The water table rises near the surface, bringing dissolved salts upward.
• Evaporation removes water and leaves salts behind in the root zone.

Salty soils stunt plant growth, reduce yields, and in severe cases make land unusable. The combination of water scarcity and salinization shrinks the area of productive land, threatens food security, and drives migration—further reinforcing desertification risks.

Desert Encroachment and Sand Dunes

Desert encroachment is the visible advance of desert conditions into neighboring landscapes—croplands, pastures, and villages. As plant roots disappear and soils loosen, wind mobilizes sand and fine particles, building dunes that can bury fields, roads, and homes.

In areas undergoing desertification, dune formation speeds up:

• Wind erosion picks up unprotected soil and deposits it as shifting dunes.
• Dunes cut off access to water sources and grazing areas.
• Sand movement grinds away remaining vegetation and topsoil.

Once dunes begin to move across the landscape, stabilizing them requires targeted measures: windbreaks, dune-fixing vegetation, fencing, and sometimes physical structures—all of which are easier and cheaper to implement before degradation becomes severe.

Soil Fertility Loss and Dryland Ecosystems

One of the most damaging outcomes of desertification is the loss of soil fertility. Without organic matter, microbial life, and a protective plant cover, soils lose their ability to provide nutrients, store carbon, and retain water.

Major drivers of fertility loss include:

• Topsoil erosion that removes the most nutrient-rich layer.
• Salinization that damages plant roots and soil structure.
• Deforestation and overgrazing, which reduce litter fall and organic inputs.

Dryland ecosystems—arid, semi-arid, and dry sub-humid areas—cover a large share of the Earth’s surface and support hundreds of millions of people. When these ecosystems are degraded, they lose biodiversity, resilience, and the ability to buffer communities against climate shocks.

Sustainable Land Management: Solutions on the Ground

Sustainable land management (SLM) offers proven tools to slow, halt, and in many cases reverse desertification. Key practices include:

• Agroforestry: Integrating trees with crops or livestock to protect soil, improve fertility, and diversify income.
• Conservation agriculture: Reduced tillage, permanent soil cover, and crop rotations that build soil structure and organic matter.
• Improved grazing management: Rotational grazing, resting degraded pastures, and aligning herd size with carrying capacity.
• Efficient irrigation: Drip systems, precise scheduling, and drainage that economize water use and limit salinity buildup.
• Local and Indigenous knowledge: Time-tested water harvesting, terracing, and planting methods adapted to dryland conditions.

When SLM practices are supported by secure land tenure, local participation, and access to finance, they can restore productivity and reduce pressure to clear new lands.

Land Degradation Neutrality (LDN)

The United Nations Convention to Combat Desertification (UNCCD) promotes Land Degradation Neutrality (LDN)—a goal where any new land degradation is balanced by restoration elsewhere, so the overall amount and quality of productive land is stable or increasing.

Achieving LDN requires:

• Preventing further degradation through better land use planning and SLM.
• Restoring degraded lands via reforestation, assisted natural regeneration, and soil rehabilitation.
• Monitoring land condition over time to track progress and adjust strategies.

LDN ties together climate, biodiversity, and development goals, recognizing that healthy land is fundamental to all three.

Recognizing Early Signs of Desertification

Early detection makes intervention more effective and less costly. Warning signs include:

• Increasing areas of bare soil and crusted ground.
• More frequent dust storms and visible wind or water erosion features.
• Declining vegetation cover and a shift from perennial plants to sparse annuals or shrubs.
• Falling crop yields or reduced pasture productivity despite similar inputs.
• Rising soil salinity, hardpans, or compaction.
• Household income drops, out-migration, or conflict over remaining fertile land and water.

Desert Rehabilitation and “Green Wall” Projects

Desert rehabilitation focuses on restoring productivity, biodiversity, and ecological function to degraded drylands. Core actions include:

• Reforestation and tree belts to reduce wind speeds, stabilize dunes, and rebuild soil.
• Soil fertility improvement with compost, cover crops, and conservation tillage.
• Water harvesting (bunds, terraces, swales) and efficient irrigation to maximize each drop.

Large-scale “green wall” projects demonstrate what is possible at continental scale. The Great Green Wall initiative in Africa aims to restore millions of hectares across the Sahel, sequester carbon, and create rural jobs by establishing bands of trees and tree plantations in degraded areas.

In China, the Three-North Shelter Forest Program—often called China’s Green Great Wall—was launched to slow the expansion of the Gobi Desert. The project stretches for thousands of kilometers and combines tree planting, shelterbelts, and improved land management to cut dust storms and protect farmland.

Across the Sahel, another Great Green Wall effort seeks to restore degraded land, sequester carbon, and create jobs by 2030. A common thread in these initiatives is the central role of local communities, traditional knowledge, and species adapted to harsh dryland climates—from hardy shrubs and native trees to drought-tolerant crops and, in some areas, palm trees.

The Future of Desertification Management

Managing desertification will remain a major global challenge, but the tools to address it are improving. Scaling up sustainable land management, investing in restoration, and aligning policies with Land Degradation Neutrality can turn many degraded areas back into productive, resilient landscapes.

Success depends on:

• Addressing root causes like unsustainable land use and climate change.
• Supporting community-driven restoration with secure land rights and fair incentives.
• Integrating science, local knowledge, and long-term monitoring.

Ultimately, combating desertification is about more than saving landscapes. It is about securing food systems, preserving biodiversity, stabilizing the climate, and protecting the livelihoods of millions of people who depend directly on the land.

Desertification