Agriculture Reference
In-Depth Information
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68% of the country, compared to only 28% in 1972 and 16% in 1982. Wa-
ter supply reduction affected thousands of hectares of rice and cornfields,
bringing the agricultural output to the lowest level in 20 years.
In Vietnam, drought occurred in 1998, causing a total economic loss of
about 5,000 billion Vietnamese dong. The lack of water increased the area
affected by the saltwater intrusion in the Mekong Delta, one of the main
agricultural areas of Vietnam. As a result, more than 4000 people almost
starved in the mountain and central regions of Vietnam.
E
NSO and Drought in Latin America
In Latin America, the onset of an El Niño event is associated with heavy
rains along the Pacific coast because onshore winds carry more moisture
as a result of warmer oceans, and with droughts in northeast Brazil (Ro-
pelewski and Halpert, 1987; Grimm et al., 2000). In the 19th century,
droughts during the 1877-79 period caused a famine in which 500,000
people may have died, and many others migrated. During 1982-83, yields
of crops in this region of Brazil fell by more than 50%, and 28 million
people and more than 1400 municipalities were affected (Rebello, 2000).
El Niño also causes droughts in other regions of Latin America including
Colombia, Venezuela, and Mexico (Magaña and Quintanar, 1997; Poveda
and Mesa, 1997). The drying up of reservoirs frequently disrupts hydro-
electric energy supplies and drinking water supplies for cities such as Bo-
gota, Colombia. Reduced rainfall from June to September hurt crops in an
area stretching south from Mexico through Central America to Colombia
and east to the Caribbean and northern Brazil.
[33],
Line
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0.0
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Norm
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[33],
E
NSO and Droughts in Africa
In southern Africa, the frequency of drought is on the rise. Between 1988
and 1992, more than 15 drought events affected at least 1% of the popu-
lation of this continent, compared to fewer than 5 such events between
1963 and 1967. This trend can be tied in part to the increased popu-
lation growth and cultivation of marginal lands, and to some extent to
the ENSO-related anomalies. Cane et al. (1994) noted a strong statistical
relationship between Zimbabwean maize yields and sea surface temper-
atures in the equatorial Pacific. These studies generally show that, during
ENSO episodes, large areas of southern Africa tend to experience drier than
normal conditions. Between 1875 and 1978, there were 24 ENSO events,
17 of which corresponded to a decline in rainfall at least by 10% from the
long-term median over this area (Rasmussen, 1987). Looking specifically
at Zimbabwe's rainfall records for the 20th century, the trend indicates
a clear increase in the number of below-average rainfall years and, since
the 1960s, a more severe decline in rainfall in such years (Glantz et al.,
1997). Figure 3.3 shows Zimbabwe's rainfall record from 1980 to 1992.
It should be noted that water is the major limiting factor in Zimbabwe's
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