The
Sahel region of Africa is an ecosystem that readily responds
to climatic variability and human exploitation of biospheric
resources. By definition it is the transition zone between
the wet tropical environment to the south and the Sahara
desert to the north. Fluctuations in rainfall over this region
from year to year affect livelihoods of inhabitants of the
region. Over the long-term, a systematic decrease in rainfall
may have caused in changes in land use patterns. While there
has been a tendency to refer to the desertification of the
Sahel, results from analysis of different types of satellite
and ground data have not yielded conclusive evidence of region-wide
documented
desertification.
Since the early 1980s satellite mapping of the global land biosphere
has generated long time series measurement of vegetation that
can be used as a proxy for understanding the dynamics of variability
of the Sahel. A number of studies have shown the close coupling
between rainfall and primary production in the Sahel. At present
this database of satellite observations represent one of the
most useful environmental data bases for evaluating changes over
this region. It is therefore necessary at this time to bring
together scientists who have conducted significant studies in
this region to synthesize results of satellite mapping over the
last 20 years, in addition to longer term instrumental records.
Based upon these results, these scientists will produce a clear
statement of the current state of scientific knowledge of changes
in the Sahel.
