First-Ever Global Erosivity Map Shows Areas Most Vulnerable To Erosion
This thing all things devours: Birds, beasts, trees, flowers; Gnaws iron, bites steel; Grinds hard stones to meal; Slays king, ruins town, And beats high mountain down.
The answer to this riddle is time and erosion. Erosion is a natural process, acting slowly but incessantly over time. Some types of rocks and minerals are water-soluble and will slowly dissolve, a process called chemical weathering. Physical weathering is caused by mechanical erosion factors, such as thaw-freeze cycles, rainfall or running water grinding down rocky substrates. Geologists estimate that wind and rain erode the surface of the continents by almost three feet every 20,000 to 40,000 years.
Understanding erosion is quite important in quantifying the loss of topsoil for agriculture, as well as the contamination of food and water by sediments. For example, fine-grained mud can be lethal for water organisms by clogging their respiratory systems. However, erosion is a very complex process. It depends on many factors, including climate, especially rainfall intensity, duration, and frequency. Soil type and vegetation cover also play a role.
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