Erosion is the natural process by which rock particles exposed by weathering are transported from one location to the next, typically by wind, water, ice or gravity (via mass wasting processes such as landslides). Erosion has many causes including wind, water, ice and mass wasting processes like landslides.
Erosion can create stunning landscapes while at the same time transporting harmful chemicals that pollute our environment. In this article we’ll look at ways vegetation and other natural resources can be used to reduce erosion.
Water erosion
Water erosion is one of the primary contributors to soil loss, leading to decreased nutrient and organic matter content in topsoil, as well as carrying toxic chemicals and pesticides into waterways.
Raindrops that hit bare soil can wreak havoc by dislodging its structure and scattering particles all across. Plant roots help bind these particles together and slow erosion; by contrast, deserts lack vegetation protection against erosion, making them some of the most eroded environments on Earth.
As streams travel downstream, especially along outer curves of meanders, they erode rock and soil from their paths, dissolving material into water and carrying it to the ocean.
Erosion from rivers and streams can be a serious threat to farm fields, particularly if fertilizers, agrochemicals and other contaminants enter waterways and cause flooding, mudslides or sedimentation. Erosion also has negative repercussions for water quality by adding too much sediment into rivers – this reduces oxygen content in the water, potentially decreasing oxygen availability as well as creating toxic algae blooms that threaten life on Earth.
Soil erosion
Soil erosion threatens the environment by depriving plant life of oxygen and polluting water sources, harming agriculture yields and restricting access to fresh food sources for communities relying on agriculture-based economies. Eroded soil washes away into lakes and rivers where it clogs reservoirs while encouraging algal blooms that reduce oxygen availability for fish and aquatic life.
Climate changes accelerate erosion by way of frequent, high-intensity thunderstorms, higher temperatures and drought conditions that make plants hardy enough to withstand wind erosion. Without vegetation to protect bare land from wind erosion, erosion becomes more likely. Signs of erosion include lighter-colored soil on slopes; gullies that carry off soil and crop residue; as well as reduced plant cover on knolls and shoulder slopes.
Sustainable agriculture practices such as reduced tillage and conservation agriculture aim to mitigate erosion through joint efforts among farmers as well as with their communities and local government bodies. Nonprofits play an integral part in building these relationships and providing technical assistance to farmers.
Glacier erosion
Glaciers that flow down mountains can erode the land and rocks around them, leaving behind stunning landforms such as cirques and troughs. Glacier erosion also leaves behind deposits of unsorted rock called till – composed of clay silt sand gravel boulders and more – which become landforms themselves.
A cirque is a bowl-shaped depression carved out by glaciers into bedrock, while troughs are deeper depressions formed when glaciers move downhill from higher elevations. When multiple cirques converge into one valley, this results in the creation of rock basins.
As glaciers recede with global warming, erosion from them will likely increase exponentially, creating additional sediment supply within mountain catchments and potentially impacting downstream ecosystems. Furthermore, increased erosion could increase rates of landslides and debris flows in mountains which pose serious dangers.
Human-induced erosion
Human activities have altered erosion rates worldwide over the course of millennia. Farming, deforestation and land clearing activities have significantly accelerated erosion rates in humid regions worldwide. Depletion of ground-covering plants that held soil together leaves dirt more exposed to wind-driven rainstorms as well as increases sediment accumulation along rivers streams leading to lakes and oceans.
Some humans use structures to combat erosion. Engineers create gabions – huge wireframes with multiple anchor points designed to hold boulders in place – along cliffs where homes or highways are situated, which prevent wind- and water-eroded boulders from collapsing onto buildings or cars.
Human activity displaces 10 times as much sediment than natural processes do, creating serious erosion problems in many places where people depend on growing food for sustenance. While changing farming methods and better land management can slow erosion rates, climate change makes erosion even worse and makes it harder for farmers to plant, harvest and raise livestock.