Erosion
Rain, wind and ice constantly wear down the Earth's land surface and transport the resulting broken down rock and soil to the oceans in a process called erosion.
Left unchecked, erosion would transport all the Earth's dry land into the oceans, leaving a water world. It is only the movement of the Earth's plates, which builds mountains, that stops this happening.
Geologists are quite precise about what erosion is: The term erosion only covers the transportation of Earth materials. Rock and soil are altered while still in place by a process referred to as weathering. Weathering often makes rock and soil susceptible to erosion.
Image: The wind eroded ridges in this image are known as yardangs. These examples are in the Dasht-e Lut desert, Iran. (credit: George Steinmetz/SPL)
Introduction
Erosion
TV clips (8)
play
The Wave
A beautiful rock formation in Arizona shows the wind's power.
Dr Iain Stewart visits The Wave, a rock formation in Arizona sculpted by the wind. This beautiful place is an important illustration of how the wind shapes the Earth.
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Wind feeds life
Wind transports large amounts of nutrient-rich dust around the planet.
Dr Iain Stewart explains how wind transports large amounts of nutrient-rich dust around the globe. This dust fertilizes the oceans and plants on land.
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The vanishing Med
Shifting continents caused the Mediterranean to dry out.
Dr Iain Stewart explains how, six million years ago, the continents of Europe and Africa moved together and cut off the Mediterranean Sea. He also explains how rivers erode the land and bring salt to the oceans.
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Water attacks mountains
Water is continually wearing away the land.
Dr Iain Stewart explains how water is continually eroding the land. It is only the movement of the Earth's plates that balances out water erosion and creates new land.
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Stone secrets
Where have the rivers that sculpted Yorkshire's limestone pavements gone?
Where have the rivers that sculpted Yorkshire's limestone pavements gone?
Erosion
Erosion is the process by which soil and rock are removed from the Earth's surface by natural processes such as wind or water flow, and then transported and deposited in other locations.
While erosion is a natural process, human activities have dramatically increased (by 10-40 times) the rate at which erosion is occurring globally. Excessive erosion causes problems such as desertification, decreases in agricultural productivity due to land degradation, sedimentation of waterways, and ecological collapse due to loss of the nutrient rich upper soil layers. Water and wind erosion are now the two primary causes of land degradation; combined, they are responsible for 84% of degraded acreage, making excessive erosion one of the most significant global environmental problems we face today.
Industrial agriculture, deforestation, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regards to their effect on stimulating erosion. However, there are many available alternative land use practices that can curtail or limit erosion—such as terrace-building, no-till agriculture, and revegetation of denuded soils.
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News
Warning over 'dangerous' Skipsea cliff erosion
… that the cliffs were not safe, she said....
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