presents a synthesis of predicted worldwide impacts from regional climate
change based upon IPCC global-climate-change studies, as summarized by
the USEPA (2000a,b). As indicated in the table, regions relying on singlecrop agriculture and subsistence farming, such as tropical Asia and Africa,
are particularly vulnerable to changes in weather patterns. Vector- and
water-borne diseases are expected to rise in the developing regions of the
world and in areas where extremes in weather will increase the frequency
of weather-driven disasters. Models of pasture and rangeland production
have reduced uncertainties associated with effects of global change on
pasture growth in cool, wet climates, but more focus on the linkages
between biophysical, social, and economic factors is still needed (Campbell
and Smith 2000). Furthermore, models offer opportunities to improve
understanding of attempts to mitigate climate-change impacts. For example,
a review of two international agricultural models examined the potential
effects on crop production of measures to prevent climate change (Chen
and Kates 1994).
Many of the environmental issues discussed later in this chapter are inexorably linked to global climate change: water as a scarce resource, desertification, and deforestation being prime examples. While the data are not
specific in terms of exactly where impacts will be seen, they do suggest that
the basic carrying capacities of many regions will change, which implies that
populations will need to shift in response. Overall, the impacts of global
warming, as predicted by this review, will be a major destabilizing influence
on the security of the world and will constitute a major causative factor in
population migration.
15.2.3 Land-Use Change
The various ways that people use and manage land are a prime cause of
land-cover change on the Earth. Thus, land use and land management
increasingly represent a fundamental source of change in the global environment. Land use refers to the purpose to which land is put by humans
[e.g., protected areas, forestry for timber products, plantations, row-crop
agriculture, pastures, or human settlements; Turner and Meyer (1994)]. The
major environmentally significant land-use changes today are deforestation
and desertification.
15.2.3.1 Deforestation
The impacts of deforestation range from the very subtle changes in climate
that loss of forest areas may induce to the dire life-threatening issues that
the absence of fuel wood can cause. In the context of environmental security, consider the examples of Ethiopia and Haiti. In 1900, Ethiopia was 45%
forested (Food and Agriculture Organization 1990), while today only 2.5%
of the country remains forest and woodland (World Resources Institute
1997). Likewise, Haiti has gone from a mostly tree-covered to a nearly
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change based upon IPCC global-climate-change studies, as summarized by
the USEPA (2000a,b). As indicated in the table, regions relying on singlecrop agriculture and subsistence farming, such as tropical Asia and Africa,
are particularly vulnerable to changes in weather patterns. Vector- and
water-borne diseases are expected to rise in the developing regions of the
world and in areas where extremes in weather will increase the frequency
of weather-driven disasters. Models of pasture and rangeland production
have reduced uncertainties associated with effects of global change on
pasture growth in cool, wet climates, but more focus on the linkages
between biophysical, social, and economic factors is still needed (Campbell
and Smith 2000). Furthermore, models offer opportunities to improve
understanding of attempts to mitigate climate-change impacts. For example,
a review of two international agricultural models examined the potential
effects on crop production of measures to prevent climate change (Chen
and Kates 1994).
Many of the environmental issues discussed later in this chapter are inexorably linked to global climate change: water as a scarce resource, desertification, and deforestation being prime examples. While the data are not
specific in terms of exactly where impacts will be seen, they do suggest that
the basic carrying capacities of many regions will change, which implies that
populations will need to shift in response. Overall, the impacts of global
warming, as predicted by this review, will be a major destabilizing influence
on the security of the world and will constitute a major causative factor in
population migration.
15.2.3 Land-Use Change
The various ways that people use and manage land are a prime cause of
land-cover change on the Earth. Thus, land use and land management
increasingly represent a fundamental source of change in the global environment. Land use refers to the purpose to which land is put by humans
[e.g., protected areas, forestry for timber products, plantations, row-crop
agriculture, pastures, or human settlements; Turner and Meyer (1994)]. The
major environmentally significant land-use changes today are deforestation
and desertification.
15.2.3.1 Deforestation
The impacts of deforestation range from the very subtle changes in climate
that loss of forest areas may induce to the dire life-threatening issues that
the absence of fuel wood can cause. In the context of environmental security, consider the examples of Ethiopia and Haiti. In 1900, Ethiopia was 45%
forested (Food and Agriculture Organization 1990), while today only 2.5%
of the country remains forest and woodland (World Resources Institute
1997). Likewise, Haiti has gone from a mostly tree-covered to a nearly
296
Wendell Chris King and Virginia H. Dale