Yardangs in Dasht-e Lut, Iran

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

Yardangs in Dasht-e Lut, Iran Erosion

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Erosion

Erosion is the process by which soil and rock are removed from the Earth's surface by exogenic processes such as wind or water flow, and then transported and deposited in other locations.

While erosion is a natural process, human activities have 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.

Industrial agriculture, deforestation, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion. However, there are many prevention and remediation practices that can curtail or limit erosion of denuded soils.

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