Survival in the Sahel

ing) intensifies the impact of drought and sets off a degradation
process that has its own dynamics. Wherever the carrying capacity
of natural vegetation is exceeded for a long time, the consequence
is continuing degradation of the land. 4
Drought and desertification, as Mensching showed, are
closely linked: years of water shortages and great rainfall variability
make desertification more acute. This in turn promotes
drought and intensifies its effects. 4 " Excessive destruction of natural
vegetation can in itself cause ecological degradation processes,
but these processes lead to desertification only during prolonged
periods of drought.
Desertification is not a new phenomenon; in fact it is as old
as the history of humankind in the Sahel. There have always been
shifting dunes that have buried desert settlements and destroyed
the pr-'ductive capacity of many areas that were once fertile.
Already in the 17th and mid-18th centuries travelers and traders
observed that the desert was spreading into the Sahel, which was
described as an area with the rich vegetative cover characteristic
of the humid savanna. The banks of the Senegal River once were
covered with clusters of thick-trunked trees. Today most of this
area consists of bare sand. Earlier marshlands have also disappeared.
As recently as 300 years ago extensive areas of Mauritania
were reported to have been covered with dense vegetation.
Since the beginning of the 20th century there have been
many discussions about whether the Sahel is drying up and
desertification is expanding. The debate waxed and waned as dry
spells came and went. Following the 1910-18 drought, French and
English colonial administrators believed that the Sahara was expanding
rapidly and would encroach on tne Sahel. But, as is often
the case with debates about pressing issues, interest declined as
the urgency of the problem abated, in this case with the return of
enough rainfall.
The debate resumed in the 1930s w; th the publication of The
EncroachingSahara, by Prof. Stebbing of the University of Edinburgh.
46 Stebbing postulated that the Sahara was encroaching on
the Sahel very rapidly. He supported his argument with his own
observations (primarily in northern Nigeria) and his perception
45