Environmental Engineering Reference
In-Depth Information
Figure 3.9
August rainfall in the Sahel: 1964-84
unknown medical services—such as vaccination
programmes—and led to improvements in child
nutrition and sanitation. Together these helped
to lower the death rate, and, with the birth rate
remaining high, populations grew rapidly,
doubling between 1950 and 1980 (Crawford
1985). The population of the Sahel grew at a
rate of 1 per cent per annum during the 1920s,
but by the time of the drought in the late 1960s
the rate was as high as 3 per cent (Ware 1977).
Similar values have been calculated for the
eastern part of the dry belt in Somalia (Swift
1977) and Ethiopia (Mackenzie 1987b). Initially,
even such a high rate of growth produced no
serious problems, since in the late 1950s and early
1960s a period of heavier more reliable rainfall
produced more fodder, and allowed more animals
to be kept. Crop yields increased also in the arable
areas. Other changes, with potentially serious
consequences, were taking place at the same time,
however. In the southern areas of the Sahel, basic
subsistence farming was increasingly replaced by
the cash-cropping of such commodities as
peanuts and cotton. The way of life of the
nomads had already been changed by the
establishment of political boundaries in the
nineteenth century, and the introduction of cash-
cropping further restricted their ability to move
as the seasons dictated. Commercialization had
been introduced into the nomadic community
also, and in some areas market influences
encouraged the maintenance of herds larger than
the carrying capacity of the land. This was made
possible, to some extent by the drilling or digging
of new wells, but as Ware (1977) has pointed
out, the provision of additional water without a
parallel provision of additional pasture only
served to aggravate ecological problems. All of
these changes were seen as improvements when
they were introduced, and from a socio-economic
point of view they undoubtedly were.
Ecologically, however, they were suspect, and,
in combination with the dry years of the 1960s,
1970s and 1980s, they contributed to disaster.
The grass and other forage dried out during
the drought, reducing the fodder available for
the animals. The larger herds—which had
Source:
After Cross (1985a)
disease and death. In contrast, good years are
those in which the ITCZ, with its accompanying
rain, moves farther north than normal, or remains
at its poleward limits for a few extra days or
even weeks.
In the past, this variability was very much part
of the way of life of the drought-prone areas in
sub-Saharan Africa. The drought of 1968 to 1973
in the Sahel was the third major dry spell to hit
the area this century, and although the years
following 1973 were wetter, by 1980 drier
conditions had returned (see Figure 3.9). By 1985
parts of the region were again experiencing fully
fledged drought (Cross 1985a). A return to
average rainfall in 1988 provided some respite,
but it was short-lived, and in 1990 conditions
again equalled those during the devastating
droughts of 1972 and 1973 (Pearce 1991b).
Much as the population must have suffered in
the past, there was little they could do about it,
and few on the outside showed much concern.
Like all primitive nomadic populations, the
inhabitants of the Sahel increased in good years
and decreased in bad, as a result of the checks
and balances built into the environment.
That situation has changed somewhat in
recent years. The introduction of new scientific
medicine, limited though it may have been by
Western standards, brought with it previously
