graphic characteristics showed heterogeneous patterns that challenged simple explanations of land use change and showed the need for local strategies for ecosystem protection.14

Partly as a result of these research insights, countries such as Brazil have altered taxation and subsidy structures that favored ranching and have adopted policies for more sustainable development of forest lands. Multilateral development agencies now undertake environmental assessments for transportation and other development projects. Popular accounts are now more sensitive to the varied causes and responses to Amazonian deforestation.

Consequences of Climate Change and Variability at the Regional Level

Researchers have compiled data on overall losses from climatic disasters and have shown that economic damages are increasing dramatically, especially in the United States. For example, hurricane and flood losses have reached more than $1 billion annually in recent years and have stressed both federal disaster relief and private insurance systems.15 Although these increased disaster losses may be due to climate change, much of the increase is a result of increasing vulnerability resulting from more people living in hazard-prone locations, increasing property prices, and inadequate land use and building regulations. In the developing world, millions of people have been displaced by cyclones, flooding, and droughts, as population growth, migration, and poverty expose more people to climatic extremes.16 The human consequences of climate change and variability depend critically on the vulnerability of human populations and on their ability to adapt, as well as on climatic events.

Studies have also identified a serious threat of changes in the patterns of diseases and pests associated with climate change and variability. 17 The 1993 Midwest floods were associated with multiple epidemics in the United States. Heavy rains in Milwaukee overwhelmed the sanitation system, creating a plume of farm waste and contaminated runoff in Lake Michigan that later entered the water supply, resulting in a large outbreak of Cryptosporidium (400,000 cases, with more than 100 deaths). In Queens, New York, an exceptionally hot, humid summer boosted local mosquito populations, leading to local transmission of malaria. In the southwestern United States, intense rains provided a sudden burst of food supplies for rodents, following a six-year drought that significantly reduced rodent predators (owls, coyotes, and snakes). The 10-fold rise in rodents led to transmission of a “new” disease—hantavirus pulmonary syndrome—with a case fatality rate of 50 percent.

In Southern Africa, prolonged drought, punctuated by heavy rains in 1994, precipitated an upsurge of rodents, crippling agricultural yields in Zimbabwe and leading to plague in Mozambique and Malawi. In India in 1994 flooding following a summer of 51°C temperatures across the plains led to an outbreak of rodent-borne plague, as houses with stored grains heated up, generating clouds of fleas. In addition to severe human losses in the affected regions, measured economic

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