DEFINITION OF SAHEL, AFRICA

A large shifting area of sub-Saharan Africa,

north of the savannas of southern Africa. The Sahel includes

parts of Senegal, Mauritania, Mali, Burkina Faso, Nigeria,

Niger, Chad, Sudan, Ethiopia, and Eritrea.

The Sahel region offers one of the world’s most tragic

examples of how poorly managed agricultural practices, when

mixed with long-term drought conditions, can lead to disaster

and permanent desertification. Sahel means boundary in Arabic,

and the Sahel forms the southern boundary of the world’s

largest desert, the Sahara. It is home to about 25 million people,

most of whom are nomadic herders and subsistence farmers.

In the summer months of June and July, heating normally

causes air to rise and this is replaced by moist air from the

Atlantic, which brings 14–23 inches (35.5–58.5 cm) of rain

per year. In the Sahel the normal northward movement of the

wet intertropical convergence zone stopped during an El-

Niño-Southern Oscillation (ENSO) event in 1968. Further climatic

changes in the 1970s led to only about half of the

normal rain falling until 1975. The additional lack of moisture

brought on complications from the temperature cycles of

the northern and southern oceans becoming out of synchronicity

at this time, and the region suffered long-term

drought and permanent desertification.

As the rains continued to fail to come, and the air masses

continued to evaporate surface water, the soil moisture was

drastically reduced, which further reduced evaporation and

cloud cover. The vegetation soon died off, the soils became dry

and hot, and near surface temperatures were further increased.

Soon the plants were gone, the soils were exposed to the wind,

and the region became plagued with blowing dust and sand.

Approximately 200,000 people died, and 12 million head of

livestock perished. Parts of the region were altered to desert,

with little chance of returning to the previous state.

The desertification of the Sahel was enhanced by the

agricultural practices of the people of the region. Nomadic

and marginal agriculture was strongly dependent on the monsoon,

and when the rains did not come for several years, the

natural and planted crops died and many of the remaining

plants were used as fuel for fires to offset the cost of fuel.

This practice greatly accelerated the desertification process.

The Sahara is now thought to be overtaking the Sahel by

migrating southward at approximately three miles per year

(4.8 km/yr). Much of Africa including the Sahel region has

become increasingly dry and desert-like over the past hundred

years or more, and any attempts to restart agriculture

and repopulate regions evacuated during previous famines in

this region may be fruitless and lead to further loss of life.

See also DESERT; SAHARA DESERT.

salt dome See DIAPIR.

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