Around a quarter of a million tons of topsoil are washed from the deforested mountain slopes of Nepal alone each year. On a global scale, about eleven million hectares of arable lands are annually lost through erosion, desertification and toxification; processes which are greatly encouraged by poor resource management. 10 It is human activity that causes natural erosion rates to increase many times over. Steep slopes are cultivated without terracing, irrigation projects are poorly developed and livestock overgraze grassland.