The Economics of Desertification, Land Degradation, and Drought

When analyzing the current situation of land degradation, which includes the decrease in
vegetation cover in particular, the focus is predominantly on visible indicators of consequences of the
process (see the study reviews in Appendix A, Table A.1 and Table A.2). The satellite data do not
include forms of degradation that cannot be detected remotely. Remote sensing is therefore limited to
an evaluation of an aggregated outcome (vegetation cover) that is the result of various interacting
factors on the ground, with one of those being land degradation. As observed earlier, although NDVI
may indicate land degradation, it may also be misleading if factors other than land degradation lead to
vegetation change. Recent approaches that take into account socioeconomic determinants of land
degradation or improvement have attempted to address past weaknesses. For example, GLADIS
combined multiple socioeconomic factors and biophysical measurements into indexes; however,
depending on the factors chosen and their combination and weighting, the results changed. A more
systematic approach and theoretical underpinnings are still needed to determine which factors to
select, how they interact and influence each other, and how they affect vegetation.
The general lack of data in developing countries makes land degradation assessment in a
broad view sometimes difficult. However, availability of satellite imagery data has generally
alleviated this data dearth problem in developing countries. Methods to assess land degradation are as
manifold as the process itself. The use of radar and microwave remote sensing must be integrated
more often in actual land degradation assessment techniques. A global approach is needed that uses
standardized methods and a bottom-up technique that starts at the local level, enabling the adaptation
of global analysis data to the local level. Global monitoring is still a challenge. As pointed out earlier,
there is still a lack of precise data on the global level. Global maps on land degradation and
desertification do give good overviews, but, as pointed out within the GLASOD, GLADA, and
GLADIS approaches, information cannot be transferred to the local level. This local-level information
is needed for policymakers and for more adapted research on land use management.
Table 2.3 summarizes the strengths and weaknesses of the land degradation and improvement
approaches used in the past and reviewed in this study.
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