Agriculture Impacts: Droughts, Floods, and Regional Famines
Scientists predict that global warming will significantly change patterns of agricultural production. More moderate temperatures
or increased precipitation may lead to a marginal gain in agricultural productivity in some regions. But increased heat stress,
decreased soil moisture, greater frequency and severity of drought and floods, and the proliferation of harmful insects and
disease will likely devastate agricultural yields in many others, affecting the availability of food in world markets and raising
food prices.
When the likelihood of catastrophic events such as droughts and floods is factored in, it is easy to see that the impacts on
agriculture will be expensive. For example, the severe drought in the U.S. in 1988 lowered crop yields by 30 percent, cost an
estimated $40 billion ($1988), and significantly increased the world price of grain (McMichael, 1993, p. 162; Cline, 1992, p.
89). Scientists predict a 5 to 50 percent increase in the frequency and severity of droughts and floods as a result of global
warming (Rind, et al., 1990). Based on the $40 billion figure, a 5 to 50 percent increase in the incidence of severe droughts as
a result of global warming could lead to annual drought-related agricultural losses of as much as $18 billion (Cline, 1992, p.
94).
Global climate change is also expected to produce northward shifts in cultivated land, with some regions faring worse than
others. In the U.S., for example, states that depend on agriculture as a primary economic activity, such as those in the
Southeast and the Southern Plains, could face severe economic disruption if global warming lowers agricultural yields.
Worldwide, the most harmful effects of global warming on agriculture will likely fall on areas that can least afford them. For
example, many developing countries, which already face problems of hunger due to overpopulation, political strife, and existing
climatic events such as droughts, will likely experience additional famines as global warming reduces crop yields (Reilly, 1995;
Rosenzweig and Parry, 1994). The consequences of increased famine will extend beyond the directly affected regions.
Developed countries, for example, could face an increase in humanitarian and financial responsibility to assist those countries in
need. Further reductions in crop yields could have a significant impact on both domestic and world food prices.
Several studies assume that farmers will be able to adapt to changing climate conditions by switching crops, altering fertilization
and irrigation patterns, and even relocating (Wolfe, 1995, p. 10; VandeVeer and Pierce, 1994, p. 595). The costs of such
adaptation, however, are likely to be quite high. For example, changes in crops may require considerable investments in new
farm equipment in order to accommodate different planting and harvesting requirements. And agricultural expansion into
regions that become more favorable for certain crops could create significant problems in those areas due to factors such as
competing pressures for land use and changing infrastructure needs such as the development of dams and reservoirs for
irrigation.
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