Major Causes of Land Degradation: Global FAO Assessment and Impact Analysis

Land degradation is one of the most pressing environmental challenges of our time. According to the Food and Agriculture Organization (FAO), approximately 1.7 billion people live in areas where crop yields have declined due to human-driven land degradation. But what exactly causes this widespread damage to the planet’s productive land? The FAO identifies four major contributors – overgrazing, deforestation, agriculture, and industrial activities – each playing a distinct role in stripping the earth of its capacity to sustain life. Let’s break down these causes and understand how they work.

The four major global contributors to land degradation
Overgrazing: the single largest cause
How overgrazing damages the land
Deforestation and removal of natural vegetation
What happens when forests disappear
Mining and industrial development
How mining degrades land
Major environmental effects
Agricultural practices and chemical contamination
How chemical agriculture degrades soil
The toxic soil cycle
Impacts on groundwater recharge
The interconnected nature of land degradation

The four major global contributors to land degradation

The FAO’s Global Assessment of Human-Induced Soil Degradation (GLASOD) provides one of the most widely cited breakdowns of global land degradation causes. According to this assessment, the four primary factors are:

Overgrazing accounts for the largest share at 36.2% of global land degradation. Deforestation and removal of natural vegetation follows closely at 34.5%. Agricultural activities contribute 28.1%, and industrial and other activities account for the remaining 1.2%. While industrial activities represent the smallest share, their localised impacts can be devastating. Together, these four factors explain virtually all human-induced soil degradation worldwide.

Overgrazing: the single largest cause

Overgrazing occurs when livestock are allowed to graze natural pastures at levels that exceed the land’s carrying capacity. This is not just about too many animals on too little land – it’s about sustained pressure that prevents vegetation from recovering between grazing cycles.

How overgrazing damages the land

When livestock continuously strip vegetation from rangeland, the soil loses its protective cover. Exposed soil becomes vulnerable to both wind and water erosion. Over time, this leads to a decline in soil organic matter, loss of nutrient-rich topsoil, and compaction from animal trampling. In arid and semi-arid regions, overgrazing can trigger desertification and bush encroachment, where woody shrubs replace palatable grasses. This shift reduces biodiversity and lowers the land’s productivity for both livestock and ecosystems.

The problem is especially severe in regions where grazing rights are communal but livestock ownership is private. In these settings, it becomes extremely difficult to regulate stocking levels, and the land suffers as a result. Countries across Asia, Sub-Saharan Africa, and parts of South America are heavily affected.

Deforestation and removal of natural vegetation

Deforestation – the near-complete removal of forest cover, usually for agriculture, urban development, or commercial logging – is the second largest driver of land degradation globally. Forests are far more than just trees. They anchor soil, regulate water cycles, and maintain microclimate conditions that support surrounding ecosystems.

What happens when forests disappear

When forests are cleared, the exposed soil is left directly vulnerable to erosion by wind and rain. Without root systems to hold the soil in place, fertile topsoil is rapidly washed away. This leads to a cascade of problems: reduced soil fertility, increased flood risk, landslides on sloping terrain, and sedimentation of rivers and waterways downstream.

According to the FAO’s Global Forest Resources Assessment, cropland expansion accounts for nearly half of all global deforestation, with new pasture creation responsible for an additional 38.5%. The negative effects extend beyond the immediate site – studies show that large-scale deforestation in the tropics can alter regional rainfall patterns, ultimately impacting rainfed agriculture across entire continents.

In countries like Nepal, forests have been severely degraded due to excessive harvesting for fuelwood and animal fodder. In India, upland forests have faced major overgrazing pressures. As forests shrink, communities often burn crop residues and animal manure for fuel instead of returning them to the soil, further depleting soil nutrients.

Mining and industrial development

While industrial activities contribute only about 1.2% to global land degradation, their impacts are highly concentrated and often irreversible at the local level. Mining, construction, and urban expansion drive deforestation, remove vegetation cover, and fundamentally alter landscapes.

How mining degrades land

Mining operations – especially open-cast or surface mining – involve removing massive quantities of overlying soil and rock (called overburden) to access mineral deposits. This process destroys vegetation, strips away nutrient-rich topsoil, and exposes the land to severe wind and water erosion. The World Atlas of Desertification notes that waste material from a single industrial mine can extend across hundreds to thousands of hectares, threatening surrounding soils, freshwater, and vegetation through dust generation and erosion.

Major environmental effects

The consequences of mining-related land degradation are significant. Wasteland formation is common, as mined-out areas are often left barren and unable to support vegetation naturally. Floods and landslides become more frequent because the removal of vegetation and alteration of natural drainage patterns increases surface runoff. Ground subsidence – the sinking or collapse of the land surface – occurs when underground mining creates hollow spaces (goafs) that eventually cave in. Research published in PMC documents how coal mining-related land subsidence leads to increased soil erosion, desertification, and declining soil fertility in affected regions.

Additionally, mining operations often use toxic substances like cyanide and mercury, particularly in gold extraction. Accidental spills from these operations can contaminate soil and water systems for hundreds of kilometres downstream, affecting both ecosystems and human communities.

Agricultural practices and chemical contamination

Agriculture contributes 28.1% to global land degradation, and modern farming methods are a major part of the problem. While chemical inputs like fertilizers, pesticides, and weedicides have boosted short-term crop yields, their long-term effects on soil health are deeply concerning.

How chemical agriculture degrades soil

Chemical fertilizers, when overused, alter the soil’s natural chemical properties. Research shows that long-term application of chemical fertilizers leads to soil acidification, excessive nutrient residues (particularly ammonium and phosphorus), and a decline in organic matter. These changes fundamentally undermine the soil’s capacity to sustain healthy plant growth over time.

Pesticides and weedicides add another layer of damage. Studies document that heavy pesticide use causes populations of beneficial soil microorganisms to decline. These microorganisms – bacteria, fungi, and other tiny organisms – play a critical role in nutrient cycling, organic matter decomposition, and maintaining soil structure. When they are killed off by toxic chemicals, the soil loses its biological vitality.

The toxic soil cycle

The damage from chemical-intensive farming creates a self-reinforcing cycle. As soil microorganisms die, the soil’s natural fertility drops. Farmers respond by applying more chemical fertilizers to maintain yields, which further degrades the soil. Over time, this leads to what can be described as toxic soils – land that is chemically contaminated, biologically depleted, and structurally compromised.

Beyond soil damage, these chemicals have wider environmental impacts. Excess fertilizers and pesticides leach into groundwater, contaminating drinking water sources. Runoff carries these substances into rivers and lakes, causing problems like algal blooms and aquatic dead zones. According to research published on IntechOpen, the overuse of synthetic chemicals also contributes to greenhouse gas emissions and poses serious risks to human and animal health through bioaccumulation in the food chain.

Impacts on groundwater recharge

Chemical contamination also impedes groundwater recharge. Healthy soil acts as a natural filter, allowing rainwater to percolate through and replenish underground aquifers. When soil structure is damaged by chemical overuse and compaction from heavy machinery, its ability to absorb water decreases significantly. Rainwater runs off the surface instead of seeping in, reducing groundwater levels and increasing the risk of both drought and flooding.

The interconnected nature of land degradation

It’s important to understand that these four causes rarely act in isolation. Deforestation often leads to overgrazing on newly cleared land. Agricultural expansion drives further forest removal. Mining creates wastelands that take decades to rehabilitate. And chemical contamination makes already degraded land even harder to restore.

The FAO’s 2025 report emphasised this interconnected reality, noting that deforestation, overgrazing, and intensive cropping are collectively degrading the world’s productive land base and threatening rural livelihoods. However, the report also offered an encouraging finding – reversing just 10% of human-induced degradation on existing croplands could produce enough food to feed an additional 154 million people annually.

Addressing land degradation requires integrated strategies. This means enforcing deforestation controls, managing livestock stocking rates, transitioning to sustainable agricultural practices that reduce chemical dependence, and enforcing stricter environmental regulations on mining and industrial development. More than 130 countries have already pledged to achieve Land Degradation Neutrality under the United Nations Convention to Combat Desertification (UNCCD), signalling a growing global commitment to reversing this crisis.

What do you think? Given that overgrazing and deforestation together account for over 70% of global land degradation, should international policy focus more on regulating land use in pastoral and forested regions? And in your own community, have you noticed any effects of chemical-intensive farming on local soil or water quality?

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Table of Contents

The four major global contributors to land degradation 🔗

Overgrazing: the single largest cause 🔗

How overgrazing damages the land 🔗

Deforestation and removal of natural vegetation 🔗

What happens when forests disappear 🔗

Mining and industrial development 🔗

How mining degrades land 🔗

Major environmental effects 🔗

Agricultural practices and chemical contamination 🔗

How chemical agriculture degrades soil 🔗

The toxic soil cycle 🔗

Impacts on groundwater recharge 🔗

The interconnected nature of land degradation 🔗