Geoscience Reference
In-Depth Information
Drought as a
Hazard
CHAPTER 5
Drought onset is aperiodic, slow, and insidious. As a
result, communities in drought-prone areas must be
constantly prepared to insulate themselves from the
probability of drought and finally, when overwhelmed,
to ensure survival. However, a community's response to
drought varies depending upon its social and economic
structure. This chapter examines first the pre-colonial
response of societies to drought. This is followed by an
examination of drought response in modern societies.
While westernized countries have generally fared
better than underdeveloped countries, it will be shown
that national perception and policy ultimately deter-
mine success in drought mitigation. The chapter
concludes by comparing the success of drought relief
organized by world organizations, mainly the United
Nations, to that of private responses such as the Band
Aid appeal headed by Bob Geldof in response to the
Ethiopian drought of 1983-1984.
INTRODUCTION
Drought and famine have plagued urban-agricultural
societies since civilizations first developed. While many
definitions exist, drought can be defined simply as an
extended period of rainfall deficit during which agri-
cultural biomass is severely curtailed. In some parts of
the world, such as the north-east United States and
southern England, a drought may have more of an
effect on urban water supplies than on agriculture. The
definition of drought, including the period of rainfall
deficit prior to the event, varies worldwide. In southern
Canada, for instance, a drought is any period where no
rain has fallen in 30 days. Lack of rain for this length of
time can severely reduce crop yields in an area where
crops are sown, grown, and harvested in a period of
three to four months. In Australia, such a definition is
meaningless, as most of the country receives no rainfall
for at least one 30-day period per year. Indeed, in
tropical areas subject to monsoons, drought conditions
occur each dry season: most of tropical Australia, even
in coastal regions, endures a rainless dry season lasting
several months. In Australia, drought is usually defined
as a calendar year in which rainfall registers in the
lower 10 per cent of all the records. Unfortunately, in
the southern hemisphere, a calendar year splits the
summer growing season in two. A more effective crite-
rion for drought declaration should consider abnor-
mally low rainfall in the summer growing season.
PRE-COLONIAL RESPONSE TO
DROUGHT
(Garcia, 1972; Morren, 1983; Watts, 1983; Scott, 1984)
In nomadic settings, there is a heavy reliance upon
social interaction as drought develops. The !Kung of
the Kalahari Desert of south-west Africa congregated
around permanent water holes only during the dry
season (see Figure 5.1 for the location of major African
placenames). If conditions became wetter and more
 
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