Sandstorm in a Teacup? Understanding Desertification

Abstract

In 1987 UNEP stated that 27 million hectares of productive land were being lost to desertification each year, at which rate not one hectare of productive land would remain on earth in 200 years time. Despite being widely perceived as an environmental issue of major importance, desertification has been subject to considerable confusion, misinterpretation and lack of clarity regarding its characteristics and occurrence. This paper examines recent scientific developments that enhance understanding of desertification processes but raise doubts about some previous assessments of the problem. In particular, natural fluctuations in dryland vegetation communities caused by inherent environmental instability need to be distinguished from degradation of the soil system caused by human activities. Improved satellite-based monitoring of environmental changes in Africa, and a recent global assessment of human-induced land degradation by ISRIC/UNEP, suggest previous assessments ofdesertification may have over-estimated the worldwide extent of the phenomenon by a factor of three.