Erosion is a natural process that plays an essential role in shaping Earth’s most breathtaking features, driven by forces such as water, wind and ice.
Weathering, or the gradual break down of rocks and materials, is also part of erosion. Deposition occurs as small pieces of Earth travel from place to place.
Water
Erosion often happens when water carries away soil through rainfall, surface runoff, rivers or ocean waves. While this usually takes place slowly over time (unless triggered by floodwaters), plant roots that hold soil together can help stop its loss to erosion more quickly than just mulch coverings covering soil does.
Wind erosion is another key contributor to its cause, transporting dust and sand between areas like Badain Jaran in China and even forming towering dunes like those seen at Badain Jaran. Wind can also polish rocks and cliffs into their characteristic reddish color known as desert varnish.
Erosion is an integral part of weathering processes on Earth, helping shape some of its most fascinating features and ecosystems. Unfortunately, erosion can also be harmful by carrying pollutants from place to place – every five seconds the equivalent of one soccer field worth of soil is washed into global waterways from farms or farms plowed with fertilizers and pesticides that kill off fish populations as they reach lakes and rivers where they will poison aquatic environments and plants alike.
Ice
Glaciers erode Earth in various ways. These processes include glacial abrasion – scoring of rock surfaces by scraping action of ice; and plucking, in which chunks of gravel-sized to school bus sized rock are broken loose from bedrock and carried off by glaciers1.
Melting glacier ice can also result in thermal erosion, which erodes soil and rocks as the glacier retreats, producing landforms such as fjords.
Ice erosion can alter the shape of mountains and valleys, as rivers move through narrow V-shaped valleys with steep sides. When this happens, the river can transform it into U-shaped valleys with steep sidewalls in an event known as mass wasting; unlike other forms of erosion it moves huge amounts of material quickly through gravity alone and poses serious threats to communities nearby – similar to what would happen if an avalanche moved onto communities from below. Furthermore, unlike moving ice or water masses wasting does not involve moving ice or water bodies moving in any way – just gravity alone causes this transformation of canyon walls into U-shaped valleys with steep sidewalls a mass wasting event can also threaten communities – it poses serious threats compared with moving ice or water moving along its trajectory.
Wind
Erosion with wind occurs when a strong breeze or storm sweeps away soil particles, carrying fine silt-and-clay size particles over longer distances before eventually depositing in new places. Meanwhile, larger sand-sized particles travel shorter distances. Erosion caused by waves striking coastal cliffs also contributes to this form of erosion by creating caves, bore holes, or dislodging sea stacks altogether.
Soil clods that have been aggregated together and covered with living plants help prevent wind erosion, while simultaneously helping retain water for plant growth. Their clumpiness depends on moisture content, compaction level, organic matter levels and clay contents in the soil.
Human activity can either accelerate or reduce erosion. Activities like intensive agriculture, road building and climate change all play a part in increasing it, while vegetation growth, proper farming methods and building on slopes may slow its progress. Rock sculpted by wind is often an amazing display of art known as ventifacts.
Soil
Soil erosion is a global concern. It erodes away fertile layers that are essential for growing crops, leading to lower crop production. Degraded soil tends to have increased chemical runoff that pollutes waterways and threatens fish populations; additionally it contributes to buildups of sediment in rivers which clogs them and causes flooding.
Lands without dense vegetation are particularly vulnerable to erosion from both rainfall and wind, with plant roots acting to bind soil particles together, helping mitigate their impact and thus prevent further erosion.
Erosion rates depend on many factors in a landscape, including climate, topography and vegetation. Climate change with its rising temperatures and more extreme weather events has increased erosion rates; PLT’s Carbon & Climate E-Unit provides activities to help students understand this topic. Land clearing for agriculture or mining operations also increases erosion risks due to being exposed to heavy rainfall or winds.