Desertification and land degradation: origins, processes and solutions

Table of Contents

1. Authors and acknowledgements
2. Introduction
   1. Aims
   2. Definitions and key concepts
   3. Synthesis of previous and ongoing projects
   4. Key issues and outline
3. Evolution of desertification in the Mediterranean
   1. Climatic fluctuation
   2. Human influence
4. Primary drivers of desertification
   1. Biophysical and socio-economic causes
   2. Pathways of desertification
   3. Driving forces in the Mediterranean
   4. Synthesis of causes for DESIRE hotspots
   5. Conclusions
5. Processes and consequences of desertification in the Mediterranean
   1. Socio-economic and political factors
   2. Biophysical processes
   3. Conclusions
6. Indicators: monitoring desertification
   1. History of monitoring
   2. Indicators
   3. Monitoring and mapping techniques
   4. Concluding remarks
7. Modelling desertification
   1. Definition of modelling
   2. Model types
   3. Biophysical modelling
   4. Socio-economic and participatory modelling
   5. Gaps and progression in modelling
8. Solutions
   1. Biophysical solutions
   2. Political and socio-economic solutions
9. References

Introduction

Land degradation occurs in all kinds of landscapes over the world. Desertification can be seen as a specific type of land degradation, occurring mainly, but not exclusively, in dryland regions. The issue of desertification has received and continues to receive much attention. This attention was caused, in first instance, by the drought that hit the Sahel in the 1970s. In 1977, through the United Nations Conference on Desertification (UNCOD), desertification was identified as a worldwide problem. The area threatened at least moderately by desertification was stated to be 3.97 billion hectares or 75.1% of the total drylands, excluding hyper-arid deserts (UNCOD, 1977). Also in the popular press, the issue of desertification got attention: 'Spread of Deserts Seen as a Catastrophe Underlying Famine' (New York Times, Jan.8^th, 1985); 'Sahara Jumps Mediterranean into Europe' (Guardian of London, Dec. 20^th, 2000). Opposed to these, also more critical headlines appeared at times: 'Threat of Encroaching Deserts May be More Myth than Fact' (New York Times, July 23^rd, 1991). The United Nations General Assembly declared 2006 the International Year of Deserts and Desertification to spread the awareness of the worlds deserts and the problem of desertification. The UNCCD (United Nations Convention the Combat Desertification) states that nowadays, 250 million people are directly affected and the livelihoods of one billion are threatened by desertification (UNCCD, 2007). In the scientific literature, desertification and related issues are widely and intensively studied and some authors question the notion that desertification is increasing.

It is, for several reasons, almost impossible to give an accurate description of the severity and extent of desertification in the world. Despite extensive research, lack of good information on extent and severity of land degradation in drylands still hampers attempts to determine its significance (Dregne, 2002). Although many different drivers for various desertification related problems have been identified, it is generally accepted that both natural (climate; biophysical characteristics) and human-induced (land use; socio-economic) factors play a role. Also, most scientists agree that participation of local stakeholders (e.g. farmers, local government etc.) is of key importance in the development and implementation of possible solutions. However, often the effects of solutions are not as successful as expected and new, alternative land use and management strategies need to be developed with the experiences of older strategies in mind.

The recently started international project DESIRE (Desertification Mitigation and Remediation of Land, a global approach for local solution) aims to contribute significantly at preventing and reducing land degradation and desertification through development of integrated conservation approaches based on the detailed understanding of the functioning of fragile semi-arid and arid ecosystems. The final goal is the establishment of promising alternative land use and management conservation strategies. One of the first goals is to look at degradation and desertification processes in an integrated way, in order to review the cause and effect links and give the conservation measures a sound scientific basis. See Appendix I for a detailed description of the project.

So-called degradation and desertification hotspots and stakeholder groups have been identified in all countries surrounding the Mediterranean and in 6 non-EU nations facing similar environmental problems. DESIRE aims to produce results that are internationally relevant, but the focus is on the Mediterranean region. Accordingly, this review is strongly focused on the Mediterranean area as well, but its scope is not exclusively limited to it.