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

Key issues and outline

In this review, knowledge about desertification is compiled from literature and projects documentation. The concept of desertification encompasses a wide range of processes, other concepts, drivers, solutions and involves people with various backgrounds and interests (e.g. farmers, scientists, policy-makers etc.). These issues are not all fully understood yet, with all their (internal) feedbacks and interrelations. Therefore, it is impossible to give a complete review of desertification and its related issues. Some key issues that emerged from this review that should be kept in mind when assessing desertification are:

• Desertification is not a new phenomenon. From the many project dedicated to desertification problems, some dramatic headlines in newspapers (see above) it may seem that desertification affects all of the drylands and that if nothing is done soon, irreversible loss of ecosystem functions will occur, resulting in disaster. However, desertification is a natural phenomenon that occurred as a consequence of changing climate during e.g. the Pleistocene (see Chapter 2).
• The drivers of desertification are both human and natural. This key issue is assessed in Chapters 3 and 4 but reappears in everything related top desertification. The dry climate and short, intense rainstorms are an obvious cause of many desertification problems. However, the way man treats his environment (e.g. land use and policies) is an example of the human influence on desertification. In line with this view, we think that solutions to desertification problems should not only be sought in biophysically oriented approaches, but also that policies and local land users should be involved in finding solutions.

Outline

• In Chapter 1 an introduction is given to the subject of desertification, the aims of this review are stated and definitions of some key concepts are given. A synthesis is given of projects that assess or have assessed desertification in terms of aims, type of project and objectives.
• Chapter 2 gives a brief overview of the history and evolution of desertification in the Mediterranean. With this, desertification can be placed in an historical context which adds to the understanding of the problem.
• In Chapter 3 the primary drivers of desertification are discussed in a general way first, which shows the many interactions, feedbacks and interrelations of the problem. Two case studies are described as examples and a synthesis is given of the perceived causes of the problems in de DESIRE hotspots.
• Chapter 4 deals with processes and consequences of desertification, split up in socio-economic factors and biophysical processes. An emerging conclusion is that the problems of desertification are more of a biophysical nature, while their causes can be both biophysical and socio-economic or political (see section 4.3).
• In Chapter 5 indicators of desertification are discussed and techniques to monitor or measure these.
• In Chapter 6 various types of models which simulate desertification related issues, from large climate models (GCMs) to vegetation and hydrological models. These are models that reflect the biophysical environment. In section 6.4, socio-economic and participatory modelling is discussed.
• Finally in Chapter 7 solutions to the desertification problem are discussed, again divided in biophysical and socio-economic solutions.
• Some extra information is given in two separate appendices: Appendix 1 gives extensive information on the DESIRE project, its geographical context and the DESIRE study sites. In Appendix 2 a brief, standardized description of 48 ongoing and past desertification related projects is given.