Soil Erosion: Causes, Types, and Climate Change Connections

Soil erosion is one of the most pressing environmental challenges of our time. Every year, billions of tons of soil are washed away from farmlands, hillsides, and riverbanks worldwide. While some erosion is natural and has shaped Earth’s landscapes over millions of years, human activities have dramatically accelerated this process-with serious consequences for agriculture, water resources, and ecosystems. As climate change intensifies, the threat of soil erosion is growing even more severe. Understanding how erosion works, what drives it, and how to control it has never been more critical.

Geological vs. accelerated erosion: understanding the difference 🔗

Geological erosion is a slow, natural process that has occurred since the Earth formed. It involves the gradual wearing away of rock and soil by natural forces such as wind, water, ice, and gravity over thousands to millions of years. This type of erosion shapes canyons, valleys, and riverbeds-the spectacular landscapes we see in national parks around the world. Under natural conditions, the rate of soil formation typically keeps pace with this slow erosion, maintaining a sustainable balance.

Accelerated erosion, by contrast, occurs when human activities dramatically increase the rate of soil loss beyond what natural processes can replenish. Research published in Nature Communications reveals that humans have moved as much sediment in North America over the past century as natural processes would transfer in 700 to 3,000 years. This staggering figure illustrates just how profoundly we’ve altered the landscape.

The primary human activities driving accelerated erosion include:

Deforestation: Trees and vegetation protect soil in multiple ways. Their canopies intercept rainfall, reducing its erosive impact. Their roots anchor soil particles together. When forests are cleared for agriculture, logging, or urbanization, the soil becomes highly vulnerable. Studies indicate that deforestation can increase erosion rates by up to 1,000 times compared to forested land.

Overgrazing: When livestock graze too intensively, they remove protective plant cover and compact the soil surface with their hooves. This exposes the bare earth to rainfall impact and reduces water infiltration, leading to increased runoff and soil loss.

Agricultural practices: Conventional tillage breaks down soil aggregates and leaves fields bare during critical periods. According to Penn State Extension, farming on slopes without proper conservation techniques can increase erosion rates by 10 to 100 times, while construction sites may experience erosion rates 1,000 times greater than natural forests.

The mechanics of water erosion: detachment, transportation, and deposition 🔗

Water erosion follows a three-step process that transforms intact soil into displaced sediment. Understanding these mechanics helps explain why certain conditions lead to severe erosion while others remain stable.

Detachment 🔗

The erosion process begins when soil particles are dislodged from their original position. This happens primarily through raindrop impact. A single raindrop, approximately 5 millimeters in diameter, can strike exposed soil at velocities around 32 kilometers per hour. Larger raindrops and wind gusts can hit even harder. These impacts act like tiny explosions on the soil surface, displacing particles and destroying soil structure. Detached particles can travel as much as 0.6 meters vertically and 1.5 meters horizontally from a single raindrop impact.

Transportation 🔗

Once particles are detached, flowing water carries them downslope. The transport capacity depends on the volume and velocity of runoff water. As rainwater accumulates on sloped surfaces, it gains energy and can carry increasingly larger soil particles. The faster the water moves, the more erosive power it has. On agricultural land, loosened topsoil particles are particularly vulnerable to being swept away because tillage has already broken apart the soil aggregates that would otherwise resist movement.

Deposition 🔗

When water velocity decreases-due to flatter terrain, vegetation barriers, or obstacles-it loses carrying capacity and drops its sediment load. Heavier particles settle first, while finer clays and silts may travel much further before depositing. This sediment often ends up in streams, rivers, lakes, and reservoirs, where it causes water quality problems, reduces storage capacity, and disrupts aquatic ecosystems.

Types of water erosion: from subtle to severe 🔗

Water erosion manifests in several distinct forms, each with different characteristics and impacts on the land.

Sheet erosion 🔗

Sheet erosion involves the relatively uniform removal of a thin layer of soil across an entire surface. It’s often called “invisible erosion” because there are no obvious channels or gullies to see. Instead, the topsoil gradually disappears over time. Light-colored soil on hilltops and slopes is often a telltale sign that years of sheet erosion have stripped away the darker, organic-rich topsoil. This type of erosion is particularly insidious because farmers may not notice the cumulative damage until productivity has already declined significantly.

Rill erosion 🔗

As sheet flow concentrates into defined pathways, rill erosion begins. Rills are small, shallow channels typically no more than 30 centimeters deep. They appear as parallel lines running downslope, resembling the marks left by fingers dragged through sand. While rills can often be smoothed over with normal tillage equipment, they indicate that erosion has progressed beyond the sheet stage. If left unaddressed, rills continue to deepen and widen with each rainfall event.

Gully erosion 🔗

When rills continue to grow and merge, gully erosion develops. Gullies are large channels that cannot be eliminated through routine tillage operations. They can range from less than a meter to over 20 feet deep in severe cases. Gullies create real hazards for livestock and farm equipment, can make sections of fields unusable, and continue to expand through headward erosion-where the upslope end of the gully progressively cuts backward into the landscape. Extensive gully erosion can eventually produce “badland” topography-deeply dissected terrain that’s virtually impossible to reclaim for agriculture.

Erosion control techniques: protecting the soil 🔗

Effective erosion control requires a combination of strategies that address the fundamental causes of soil loss. The goal is to keep soil covered, slow water movement, and maintain soil structure.

Terracing 🔗

Terracing is one of the oldest and most effective erosion control methods, used for centuries in mountainous regions worldwide. By creating level or gently sloping platforms across hillsides, terraces break long slopes into shorter segments. This reduces the velocity of runoff water, gives it time to infiltrate into the soil, and traps sediment before it can travel far. There are three main types of terraces: contour terraces that follow the natural slope contours, channel terraces designed to safely convey excess water to outlets, and bench terraces that create flat planting surfaces on steep slopes. Research confirms that well-designed and properly maintained terraces can substantially reduce soil erosion, though they must be combined with additional conservation practices for maximum effectiveness.

Bioengineering techniques 🔗

Bioengineering uses living plants to perform engineering functions like stabilizing slopes and reducing erosion. These techniques are cost-effective, sustainable, and environmentally friendly alternatives to hard engineering approaches. Common bioengineering methods include:

Live fascines: Bundles of living branch cuttings installed in shallow trenches to intercept surface runoff and promote plant establishment.

Vegetated cribwalls: Wooden structures filled with soil and living plant material that stabilize slopes while establishing permanent vegetation.

Brush layering: Alternating layers of live branches and soil placed on slopes to provide immediate erosion protection while plants take root.

The advantage of bioengineering is that it provides immediate structural protection while establishing permanent vegetative cover that strengthens over time as root systems develop.

Soft and hard armor approaches 🔗

Sometimes more intensive measures are needed. Soft armor techniques include erosion control blankets made from biodegradable materials, filter socks filled with compost, and geotextiles that protect soil while allowing vegetation to establish. These materials absorb raindrop energy, reduce surface runoff velocity, and help retain moisture for plant growth.

Hard armor approaches-such as riprap (rock layers), gabion baskets (wire cages filled with stones), and retaining walls-are used where erosion forces are severe or where quick stabilization is essential. While effective, these structures are more expensive and don’t provide the ecological benefits of vegetative solutions.

Climate change and soil hydrology: a worsening threat 🔗

Climate change is fundamentally altering the conditions that drive soil erosion, and the projections are concerning. According to the EU Joint Research Centre, global soil erosion rates could increase by 30 to 66 percent between 2015 and 2070 under different climate scenarios, potentially causing economic losses of up to 625 billion USD.

More intense rainfall 🔗

Climate models project a more vigorous hydrological cycle, with increased total precipitation and more frequent high-intensity rainfall events. Data from the northeastern United States shows that extreme precipitation events (greater than 3 inches per day) increased by 62 percent between 1958 and 2018, while events exceeding 5 inches per day more than doubled. Since most erosion occurs during high-intensity storms rather than gentle rains, this shift toward more extreme events dramatically increases erosion risk.

A striking example comes from North Carolina, where researchers documented that more than half of all erosion over a six-year study period occurred during just one week of highly erosive rainfall. During that single week, a conventionally tilled field lost 135 tons of soil per acre-a catastrophic amount that would take decades or centuries to replace naturally.

Changes in soil moisture and temperature 🔗

According to USDA Climate Hubs, temperature changes, altered precipitation patterns, and vegetation loss are primary climatic forces affecting erosion on both inland and coastal areas. Warmer winters mean fewer days of frozen ground and more precipitation falling as rain rather than snow. Unfrozen, rain-soaked soil is far more vulnerable to erosion than frozen ground or snow-covered surfaces.

Desertification risk 🔗

In semi-arid regions, the combination of increased drought frequency and more intense rainfall when it does occur creates a particularly dangerous pattern. Prolonged dry periods kill vegetation and leave soil exposed, while subsequent heavy rains rapidly erode the unprotected surface. Research from global modeling studies indicates that climate change impacts on soil erosion will be most severe in semi-arid regions, where these conditions are becoming increasingly common. Without intervention, this cycle can accelerate land degradation toward desertification-a point where the land can no longer support productive vegetation.

The path forward: conservation in a changing climate 🔗

Despite the scale of the challenge, research consistently shows that soil conservation practices can fully compensate for climate change impacts on erosion. Reforestation, conservation agriculture, and improved land management can not only prevent increased erosion but actually reduce it below current levels.

Key strategies include maintaining permanent soil cover through no-till farming and cover crops, which can reduce erosion by up to 90 percent compared to conventional tillage. Global modeling suggests that current conservation agriculture practices already reduce potential soil erosion by approximately 5 percent, with much greater potential if more widely adopted.

The message is clear: soil is a finite resource that takes centuries to form but can be lost in a single storm. As climate change intensifies erosion pressures, protecting this essential resource becomes ever more urgent. The technologies and techniques exist-what’s needed is the commitment to implement them at scale.

What do you think? How might changing rainfall patterns in your region affect local farmland and watersheds? What role should individual landowners, farmers, and communities play in protecting soil resources for future generations?

References

1. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/accelerated-erosion
2. https://www.nature.com/articles/s41467-020-19744-3
3. https://extension.psu.edu/soil-erosion-threat-increasing-with-climate-change
4. https://www.pmfias.com/soil-erosion-wind-and-water-erosion-rill-and-gully-erosion/
5. https://www.soils4teachers.org/erosion
6. https://passel2.unl.edu/view/lesson/5653c03d7cee/18
7. https://en.wikipedia.org/wiki/Erosion
8. https://www.larimit.com/mitigation_measures/1026/
9. https://www.ernstseed.com/bioengineering-techniques-erosion-control/
10. https://joint-research-centre.ec.europa.eu/jrc-news-and-updates/soil-erosion-water-could-lead-global-loss-usd-625-billion-2070-2024-02-09_en
11. https://www.climatehubs.usda.gov/climate-impacts/erosion
12. https://www.sciencedirect.com/science/article/pii/S0012825222000058
13. https://www.pnas.org/doi/10.1073/pnas.2001403117