The agents of erosion are waves, water, wind and ice. The process of weathering dissolves rock or breaks it down into tiny fragments, making it weak and susceptible to erosion. The agents of erosion carry fragmented rocks away, causing the earth to be worn away.
All forms of water cause erosion. In dry environments, raindrops cause splash erosion, which moves small particles of soil. The water that collects on the Earth’s surface causes sheet erosion when it starts to move towards streams. Water in streams is a powerful agent of erosion because it moves fast and can pick up and move large soil particles and objects. Streams that move slowly move fine sand. Erosion by water wears away river banks and alters the shape of coastlines. Erosion by wind occurs often in dry areas, such as deserts, where it forms sand dunes.
Strong wind erodes cliffs and rocks, making them smooth. Wind also moves volcanic ash and dust. Ice often causes erosion on mountain tops and frigid areas. As glaciers move downhill, they pick up and move rocks and sand, which scrape the ground, causing erosion. Waves in large bodies of water, such as oceans, are responsible for coastal erosion.
Human activities, such as cutting down trees, facilitate erosion. Global warming is linked to severe and frequent storms and speeds up erosion.