the earths atmosphere
... accurately modeled, and that there are too many unknowns. Some also question whether the observed climate changes might simply represent normal fluctuations in global temperature. Nonetheless, for some time there has been general agreement that at least part of the observed warming is the result of human activity, and that the problem needs to be addressed. In 1992, at the United Nations Conference on Environment and Development, over 150 nations signed a binding declaration on the need to reduce global warming. (Bender and Leone, 1-20) In 1994, however, a UN scientific advisory panel, the Intergovernmental Panel on Climate Change, concluded that reductions beyond those envisioned by the treaty would be needed to avoid global warming. The following year, the advisory panel forecast a rise in global temperature of from 1.44 to 6.3 degrees Fahrenheit by 2100 if no action is taken to cut down on the production of greenhouse gases, and a rise of from 1 to 3.6 degrees Fahrenheit even if action is taken (because of already released gases that will persist in the atmosphere). (Lubchenko, 491-497) A UN Conference on Climate Change, held in Kyoto, Japan, in 1997 resulted in an international agreement to fight global warming, which called for reductions in emissions of greenhouse gases by industrialized nations. Not all industrial countries, however, immediately signed or ratified the accord. In 2001 the G. W. Bush administration announced it would abandon the Kyoto Protocol; because the United States produces about one quarter of the world's greenhouse gases, this was regarded as a severe blow to the effort to slow global warming (see Fig. 1). Despite the American move, most other nations agreed later in the year on the details necessary to convert the agreement into a binding international treaty. Fig. 1. Mike Thompson, cartoon, Detroit Free Press 20 Feb. 2001. Improved automobile mileage, reforestation projects, energy efficiency in construction, and national support for mass transit are among relatively simpler adjustments that could significantly lower U.S. production of greenhouse gases. More aggressive adjustments include a gradual worldwide shift away from the use of fossil fuels, the elimination of chlorofluorocarbons, and the slowing of deforestation by restructuring the economies of developing nations. In 2002 the Bush administration proposed several voluntary measures for slowing the increase in, instead of reducing, emissions of greenhouses gases. Many researchers, environmentalists, and politicians are forecasting that rising world temperatures in the next century will have devastating effects on humans. Although the calamities are barely spelled out, some scholars and writers have pointed to a warmer climate's being less healthful. Referring to the world as a whole, the Intergovernmental Panel on Climate Change (IPCC) asserted "Climate change is likely to have wide-ranging and mostly adverse impacts on human health, with significant loss of life"(22-23). The IPCC report feared that increases in heat waves would cause a rise in deaths from cardiorespiratory complications. It also foresaw a rise in vector-borne diseases, such as malaria and dengue and yellow fevers. The report did acknowledge briefly that in colder regions there would be fewer cold-related deaths. The few studies that have examined the relation between warming and human health or mortality in depth have focused either on increase in the number of days of very hot weather and the resulting mortality or on the spread of infectious diseases by such vectors as mosquitoes, flies, and snails. Several major studies of the implications of global warming for the United States have neglected or claimed a lack of data on the effects on health or human welfare. This study examines the overall effect of climate and, in particular, temperatures on mortality in the United States and the value people put on a warmer environment. Rarely has any research explored people's preferences for less chilly weather. Given the circumstantial evidence that people prefer warm climates over cold, it is somewhat surprising that the effects of warming on human well being have essentially been ignored. We do know that many people upon retiring flee to southern and warmer locales. According to a survey of people turning 50 in 1996, almost 40% plan to move when they retire and the most important criterion in selecting their destination is a "more favorable climate." Folklore alleges that physicians sometimes recommend that patients escape to a warmer climate, never to a colder one. Presumably retirees, at least, find that higher temperatures improve their welfare. As air-conditioning has mitigated the rigors of hot summers, the population of the United States has been moving South and West, towards climates that enjoy less extreme cold weather. Even without warming, it is certainly possible that dengue fever or malaria could invade North America. Unfortunately, some of the government's well meaning environmental policies may make the vector more likely. The preservation of wetlands, although useful in conserving species diversity, also...