Erosion is a natural process, yet human actions can speed it up significantly. Erosion happens naturally but it can also be accelerated.
Erosion is driven primarily by three elements – water, wind and ice – as well as climate factors like topography, vegetation and tectonic activity.
Water
Rainwater floods the landscape during a thunderstorm, dislodging soil particles and altering their structures while wearing away rock fragments as it flows down hills and mountains – this process is known as mechanical weathering. Further downstream, its force deposits material that has undergone this weathering into rivers, streams and glaciers, creating new terrain features.
Wind erosion also has its share of landscape changes. When coupled with other environmental forces such as drought, dust storms or transport of materials over long distances – such as Arches National Park in Utah’s dust storms – wind can play an influential role in shaping landscapes in an irreversible manner. Arches National Park was an early victim of this process as its arch-shaped sandstone formations took shape under its forceful gusts of airborne dust and sand.
All these natural processes can accelerate erosion beyond what the land’s ability to maintain itself can withstand, and human activity adds further erosion – for instance, farming creates erosion by clearing away native vegetation and plowing the soil in preparation for planting crops.
Wind
Wind erosion occurs in dry environments where dust and sand can easily be carried away by the wind, damaging land and natural vegetation by shifting soil around and dispersing it elsewhere. Furthermore, this form of erosion removes nutrients from the soil which limits its ability to support plant life.
Wind erosion of surface material can move material for miles. This phenomenon creates desert-scape staples like sand dunes and sculptured rock formations as well as coastal features such as cliffs, stacks and arches that define their shape.
Climate change increases the likelihood of erosion in many parts of the world by making conditions hotter and drier, making it harder for plants to retain soil, increasing rainfall runoff into rivers or lakes or becoming windswept dust storms – conditions which contribute directly to erosion.
Ice
Ice is an effective agent of erosion. Glaciers erode rocks through two primary methods: abrasion/scouring and plucking. Abrasion works by grinding away at rock surfaces while plucking causes small pieces of rock to break off and be carried along, leading to U-shaped valleys, hanging valleys, cirques and pointed mountain peaks (horns) being created; eventually these rocks end up as moraines, erratics drumlins or stratified drift.
Sea ice provides Arctic coastlines with some protection from large waves during storms by acting like plastic wrap, but as it melts it exposes fragile beaches and cliffs to erosion from the churning ocean, which in turn can flood coastal villages and become a significant problem in this part of the world. Erosion remains one of the primary environmental challenges for this part of the planet.
Plants
Plants help prevent erosion by providing roots, moisture and coverage to reduce water and wind erosion.
Erosion occurs when water cannot be absorbed into the soil due to steep slopes, leading to runoff that drains away through gravity into lakes, rivers, and streams. This leads to increased erosion.
Waves on coasts can also erode rock formations to form spectacular rock arches and sea stacks, which become stunning natural landscape features. Erosion sculpts these landscape features into existence when erosion sculpts cliff faces or canyon faces – physical erosion differs from weathering because its movement-related process moves eroded material away from where it once stood and forms clastic sediments which, over time, form caves like those found at Victoria Australia’s Twelve Apostles or caves like those in Utah, USA.
Human Activity
Human activity contributes significantly to erosion. Agriculture practices like plowing fields and overgrazing livestock disturb roots that hold soil together, increasing erosion risk. Runoff can then pollute waterways. Forest logging and mining also exacerbate erosion by clearing away tree canopies that help anchor soil to its source, and by exposing topsoil to rainwater runoff and windstorms.
Human activities, like damming rivers and building buildings, also play a part in erosion. By altering water flows and decreasing their capacity to carry sediments, humans alter erosion as much as glaciers do – slowly moving sand around as they traverse across landforms to form new ones. Erosion is an integral natural process that creates new landforms while dismantling old ones.