4 Climate Change and Water Resources in West Africa …
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A modest decline in yield was observed for legumes (soya and bean) and sweet
potatoes. Incomes across all crops declined.
In most parts of Burkina Faso, changes in early and late season, dry spells, heavy
rains and pest and disease attacks affect farm productivity through physical damage to
plants (Ouoba 2013). Indeed, in the case of a late or false start of the rainy season, there
is poor growth and/or death of seedlings, the appearance of worms and caterpillars,
termite attacks, etc. Heavy rains are equally devastating. Excessive rainfalls generally
cause flooding, the uprooting of stems, the rotting of seeds (especially at the beginning
of the season), asphyxia, and sometimes non-ripening of crops. Losses in agricultural
production due to flooding of cultivated fields were estimated at Euros 2,748,727 in
1992 and Euros 97,474,891 in 1994 (MECV 2007). These factors, which lead to a
decline in agricultural production, raise the crucial issue of food security. The drop-in
rainfall also induces a drop-in millet yields, particularly in Dori in the Sahel. In the
southern areas, corn yields fell sharply due to the July, August, and September water
deficit (MECV 2007). In fact, corn is very sensitive to drought: the slightest shortage
of rainfall can jeopardize the whole harvest.
In Senegal, too, the interannual variability of rainfall affects crops. A delay in
the start of the rainy season and the annual rainfall deficit in 2014, for example,
compromised the harvest of millet and groundnuts in Louga, Thiès, and Mbour (in
the northwest of the country). Yield declines of 8–31% were recorded. In the center
(Kaolack) and the south (Ziguinchor) of the country, where rain deficits were milder,
yield decreases were less severe (Diop et al. 2016). From 1961 to 2013, yields fell
significantly in Louga and Kébémer in the north-central area of the country (Sambou
2015). Even in areas where fields are irrigated, such as the Senegal River Valley
and the Anambé Basin in Upper Casamance, the development of farming depends
on rainwater, since its abundance or scarcity determines the availability of water
resources and, therefore, yields. In the south (communities of Bona and Diacounda),
in 2007, the production of millet and corn decreased, respectively, by 38% and 40%
because of the rainfall deficit, compared to 2006 (Diédhiou 2008). Rice production
also dropped by 20% in the same year. From 1981 to 2015, the year 2007 was
noteworthy, with one of the shortest rainy seasons on record.
3.3.2 Impacts of Rainfall Variations on Pastoral Activities
Grazing prevails mainly in the Sahelian and Sudanian zones of the four countries,
where the amount of rainfall and its effects vary significantly. These factors include
late rainfalls, heavy rains, pockets of drought, early cessation of rains, and short
rainy seasons. Late rainfalls result in water shortages and, therefore, less pasture
area, as well as skin diseases and diarrhea in some animals, which often result in
death. These effects are also observed when the rainy season is too short. In Senegal,
for example, a reduction in the number of ponds compared to the pre-break period
of 1968 is observed by farmers in the areas of Sakal and Ndande (in the northwest of
the country). In contrast, increased precipitation favors milk production. The recent
73
A modest decline in yield was observed for legumes (soya and bean) and sweet
potatoes. Incomes across all crops declined.
In most parts of Burkina Faso, changes in early and late season, dry spells, heavy
rains and pest and disease attacks affect farm productivity through physical damage to
plants (Ouoba 2013). Indeed, in the case of a late or false start of the rainy season, there
is poor growth and/or death of seedlings, the appearance of worms and caterpillars,
termite attacks, etc. Heavy rains are equally devastating. Excessive rainfalls generally
cause flooding, the uprooting of stems, the rotting of seeds (especially at the beginning
of the season), asphyxia, and sometimes non-ripening of crops. Losses in agricultural
production due to flooding of cultivated fields were estimated at Euros 2,748,727 in
1992 and Euros 97,474,891 in 1994 (MECV 2007). These factors, which lead to a
decline in agricultural production, raise the crucial issue of food security. The drop-in
rainfall also induces a drop-in millet yields, particularly in Dori in the Sahel. In the
southern areas, corn yields fell sharply due to the July, August, and September water
deficit (MECV 2007). In fact, corn is very sensitive to drought: the slightest shortage
of rainfall can jeopardize the whole harvest.
In Senegal, too, the interannual variability of rainfall affects crops. A delay in
the start of the rainy season and the annual rainfall deficit in 2014, for example,
compromised the harvest of millet and groundnuts in Louga, Thiès, and Mbour (in
the northwest of the country). Yield declines of 8–31% were recorded. In the center
(Kaolack) and the south (Ziguinchor) of the country, where rain deficits were milder,
yield decreases were less severe (Diop et al. 2016). From 1961 to 2013, yields fell
significantly in Louga and Kébémer in the north-central area of the country (Sambou
2015). Even in areas where fields are irrigated, such as the Senegal River Valley
and the Anambé Basin in Upper Casamance, the development of farming depends
on rainwater, since its abundance or scarcity determines the availability of water
resources and, therefore, yields. In the south (communities of Bona and Diacounda),
in 2007, the production of millet and corn decreased, respectively, by 38% and 40%
because of the rainfall deficit, compared to 2006 (Diédhiou 2008). Rice production
also dropped by 20% in the same year. From 1981 to 2015, the year 2007 was
noteworthy, with one of the shortest rainy seasons on record.
3.3.2 Impacts of Rainfall Variations on Pastoral Activities
Grazing prevails mainly in the Sahelian and Sudanian zones of the four countries,
where the amount of rainfall and its effects vary significantly. These factors include
late rainfalls, heavy rains, pockets of drought, early cessation of rains, and short
rainy seasons. Late rainfalls result in water shortages and, therefore, less pasture
area, as well as skin diseases and diarrhea in some animals, which often result in
death. These effects are also observed when the rainy season is too short. In Senegal,
for example, a reduction in the number of ponds compared to the pre-break period
of 1968 is observed by farmers in the areas of Sakal and Ndande (in the northwest of
the country). In contrast, increased precipitation favors milk production. The recent