Causes and Consequences of Erosion – an Open Speech
Erosion can occur naturally by wind, water, and gravity. It is the eating or wearing away of land features. It is caused by a variety of factors, some natural, others man-made. Humans can also cause erosion or increase the rate of erosion through various activities. The consequences can be serious both for the natural world and for the man himself.
There are multiple causes and effects of erosion and solutions often involve conserving natural areas. The natural causes are weathering, water, ice, wind and change of temperature. The changes may be very gradual, sometimes taking millions of years and dating back to the major upheavals on the planet when the earth was very young. In the case of harder rock such as granite, surfaces are worn smooth.
Weathering also erodes exposed coastlines in temperate zones. Often cliffs and dunes simply disappear over perhaps a short period of two or three hundred years. The sea encroaches, and sometimes coastal villages are lost. There is written evidence of English villages having been lost under the waves.
The sea also plays its part in the erosion process. The Netherlands, facing the turbulent North Sea, have for centuries fought the battle against saltwater encroachment due to erosion. In another way, the sea also erodes rock fragments by friction due to the tides. The smooth pebbles on northern beaches are the result of their having rubbed together over millions of years.
The great ice-floes attached to the poles play a conspicuous part in regulating sea levels. In general, sea levels are thought to be rising, though opinions vary as to the rate. At present, many fear what is called the ‘greenhouse effect’, i.e. the punching of holes in the ozone layer due to industrial gases and the use of CFCs. Slow-moving glaciers also have an effect. Their immense power pulverizes any rocks in their path. The piles of shale at the foot of many mountains resulted from the pressure of glaciers millions of years ago.
The wind is probably the greatest single cause of erosion. Where there is no protection given to the soil, and after a period of drought or intense heat, the soil crumbles to dust and literally blows away. Man himself can either let this happen or take steps to prevent it. Rain, of course, has a dual effect. In some circumstances it can wash away the soil into river beds, where it is carried down to estuaries, often silting them so that they require dredging. Inland, and on the flat territory, rain holds the soil together. Yet rain depends on trees and foliage which causes clouds to precipitate.
The rain forests support a wide variety of animals, birds, insects, and plants, many of which can only exist in their present habitat. This is an added reason for resisting deforestation. Sooner or later when the forests have gone the climate will change from not and humid to dry. The soil will crumble and erode.
Tribes dependent on land for grazing and agriculture lose their herds, flocks and food. They become nomads or refugees and are exposed to epidemic and starvation. Erosion can cause much human suffering.
Even in temperate countries, large-scale farming is now being discouraged, for the foregoing reasons. In England, such farming has meant the destruction of hedges, ditches, and trees, aging spoiling traditional landscapes and the habitats of bird, animal and insect species.
Some erosion is natural and inevitable. Much however is caused by man. Long term conservation is essential if a man is to pass on a beautiful planet to future generations.