The rhetoric favoring stringent emissions reductions is ratcheting up. A new entry to the rhetorical fray is the claim, advanced in a study published in the Nov. 8 Lancet, that reducing emissions of carbon dioxide and other gases may prevent some 700,000 premature deaths annually around the world. The study rests on the premise that reducing the consumption of fossil fuels will reduce the emission of minute particles into the atmosphere. These particles contribute-along with many other factors-to the progress of respiratory and cardiac diseases and thus to premature deaths. But there are good reasons to doubt almost every assumption and step in the study and hence its conclusion. One little item to keep in mind is that ambient concentrations of airborne particulates are in most cities of the industrialized world already nearly at natural background levels, meaning that little significant reduction is possible no matter what we do. But even if we take the study's hesitant claim at face value, policymakers should take another factor into consideration to avoid the mistakes of myopia. Here's that factor: the lost benefits from the foregone energy use. Those benefits, too, can be measured in terms of the preservation of human lives. Broadly, we know that energy use closely correlates with economic productivity, and economic productivity with life expectancy, for a fairly simple reason: Wealthier people can afford more and better food, clothing, shelter, water treatment, medical care, transportation, and other things that promote health and longevity. Therefore, to the extent that reducing energy use entails reducing economic production or its growth, it also entails reducing energy's contribution to human health and longevity. More specifically, slowing the rate of growth of coal, oil, and natural gas consumption in developing countries will also mean slowing the rate at which these fossil fuels replace firewood, dried dung, and other biomass fuels as the primary sources of energy for heating and cooking. That is bad news for the poor in those countries. While biomass constitutes only a tiny fraction of fuel use in the industrialized world, it makes up about 40 percent of all fuel consumed in the world and therefore the majority of fuel consumed in the developing world. Biomass, alas, emits far more particulates per unit of heat than fossil fuels. The result, in the poorly ventilated huts of the Third World, is a deadly form of indoor air pollution and increased pollution in the open air. In 1993 alone, according to the World Health Organization, respiratory diseases brought on by air pollution claimed the lives of some 4 million children under age five, not to mention the deaths of people aged five and older. For people in underdeveloped countries, a switch from firewood and dried dung to fossil fuels as the primary heating and cooking fuel could prevent millions of deaths annually. But that switch will be delayed by any treaty restricting the growth of fossil fuel consumption in those countries. The lives saved by reduced fossil fuel emissions, therefore, will almost certainly be more than offset by the lives lost to prolonged dependence on dirtier fuels not covered by the treaty. This balancing of costs and benefits-not just in economic production but also in human lives-is but one example of the complex and offsetting considerations confronting policymakers in the global-warming debate. Others have been recognized for years, though unfortunately they continue to be ignored by the major media and most politicians. Here are some ignored realities: Computer models' predictions of global warming cannot be reconciled with past global temperature records; even the most sophisticated of the models remain terribly oversimplified compared with the realities of global climate; satellite measures of global average temperatures show no significant trend over the last 30 years. While it does appear that the global average temperature has increased by about one degree Fahrenheit over the last century and a half, most of the increase occurred before 1940 and therefore before the majority of the increase in greenhouse gasses in the atmosphere. Not only have Chicken Littles placed the cart before the horse, but roughly two-thirds of the increase can be attributed confidently to natural causes. Furthermore, most researchers now predict that most of whatever temperature increase does occur will take place in the winter and at night rather than in the summer and in the daytime, therefore making it unlikely that it will reduce polar ice, raise the sea level, or significantly increase evaporation and therefore expand deserts. Instead, such warming would lengthen growing seasons and diminish the need for winter heating. We can be grateful that greenhouse researchers have moderated their predictions of the expected severity of global warming. In the 1980s, many predicted an increase of around seven degrees Fahrenheit in global average temperature by the year 2100 due to a doubling of atmospheric carbon dioxide equivalents. More recent predictions are for warming of half to one-third as much, and even they remain questionable. But still other studies give reason to reduce predictions of warming even further. Just recently a team of researchers has published the results of a study supporting the view that increased temperatures are automatically moderated by increased plant growth. The study, published in the Oct. 31 issue of Science, found that El Niño and other periodic warm times indirectly cause increased plant growth about two years later. The increased plant growth, in turn, removes more CO2 from the atmosphere. The two-year lag indicates that the direct cause--standing between the temperature change and the plant response--is a change in soil microbial conditions due to the temperature change. Such findings, adding another mysterious variable to the hundreds that already must enter into climate change theory, hint at the enormously complex self-regulating nature of the whole biosphere. The new findings are reminiscent of the extensive research and writing by Sherwood Idso on the impact of carbon dioxide on plant growth. As every nursery operator knows, raising CO2 concentrations in greenhouses enhances the speed, size, and hardiness of plant growth. The Idso research suggests that the same thing happens with the giant greenhouse that we call the biosphere. Mr. Idso has shown that for every doubling of carbon dioxide concentration, plant growth increases by about a third; plants' water-use efficiency--the amount of dry matter produced for every unit of water transpired--doubles. He estimates that a significant part (though not all) of the increase in crop yields that have made food production outpace population growth in recent decades may be attributed to enhanced atmospheric CO2. He also argues that the vegetation/CO2 relationship acts as a giant thermostat, automatically keeping global temperature fluctuations within a narrow range. This happens in at least two ways. First, the increased plant growth extracts more CO2 from the atmosphere, thus reducing the amount of heat trapped by the CO2. Second, it also emits into the atmosphere more natural aerosols ("biosols"), which increase the reflection of solar heat away from the earth and back into space. Mr. Idso's theory is also unproven, but it is one example of a variety of research that indicates how an enhanced greenhouse effect, if it is low to moderate rather than at the extreme end of present predictions, could actually have more beneficial than harmful effects on people and the planet in general. Nonetheless, environmental activists and government bureaucrats continue to press for drastic reductions in fossil fuel consumption to reduce and delay global warming (leaving the poor with dried dung). The Kyoto negotiations are likely to reflect their view, despite the lack of scientific consensus supporting it. Policymakers, however, should not allow themselves to be rushed to judgment. They can point to the Intergovernmental Panel on Climate Change of the World Meteorological Organization and the United Nations Environment Program, and its report titled Climate Change 1992: The Supplementary Report to the IPCC Scientific Assessment. The IPCC compared the theoretical global warming effects over the next century of continuing with business as usual in fossil fuel use (which assumes continued increases due to economic and population growth) versus drastically reducing energy use (coupled with reductions in carbon monoxide emissions, reversing deforestation, and ending CFC emissions). Adopting strict abatement measures would make only a small difference-most likely a total of half a degree Fahrenheit over the next hundred years. Even radical projections bring a return on investment for abatement of under two degrees in an entire century. The conclusion that any difference will be minute and long-delayed follows from the projections of proponents, not opponents, of the global warming scare. Another study, published in 1994 in Climate Dynamics, concluded that it will, in the words of climatologist and leading global warming researcher Robert C. Balling, "take 70 to 100 years to detect any climatic difference between the business-as-usual scenario and the most draconian measures proposed by the IPCC." Clearly there is good reason to proceed slowly and with caution on recommendations to reduce energy use to prevent or mitigate global warming. What will prevail in Kyoto-science, or hype? Mr. Beisner's latest book, Where Garden Meets Wilderness: Evangelical Entry into the Environmental Debate, was co-published last month by Eerdmans and the Acton Institute.