"The threat of nuclear weapons and man's ability to destroy the environment are really alarming. And yet there are other almost imperceptible changes - I am thinking of the exhaustion of our natural resources, and especially of soil erosion - and these are perhaps more dangerous still, because once we begin to feel their repercussions it will be too late." (p144 of The Dalai Lama's Little Book of Inner Peace: 2002, Element Books, London)
It isn't easy to find comprehensive information on erosion, however. To a large extent this is because soil erosion does not fit neatly under any one heading: it is studied by geomorphologists, agricultural engineers, soil scientists, hydrologists and others; and is of interest to policy-makers, farmers, environmentalists and many other individuals and groups.
Despite the global nature of the problem of erosion by water, even today we do not have good information regarding the global extent of erosion by water. Data on the severity of erosion is also often limited.
The GLASOD study estimated that around 15 per cent of the Earth's ice-free land surface is afflicted by all forms of land degradation. Of this, accelerated soil erosion by water is responsible for about 56 per cent and wind erosion is responsible for about 28 per cent.
This means that the area affected by water erosion is, very roughly, around 11
million square km., and the area affected by wind erosion is around 5.5 million square km.
The area affected by tillage erosion is currently unknown.
Because soil is formed slowly, it is essentially a finite resource. The severity of the global erosion problem is only now becoming widely appreciated.