HOW SHOULD WE develop public policy on global warming? In view of the scientific uncertainties and the policy controversies, it would be sensible to go one step at a time. First, let us try to understand the issues, then army the policy alternatives, before finally examining the range of possible responses.
It is useful to realize that the public debate on climate change tends to be dominated by the extremes. The most visible players cry alarm at the impending environmental catastrophe: "We're losing the planet." In contrast, a minority believes there is nothing to worry about. That is reminiscent of Mad magazine's famous Alfred E. Newman cartoon. "What, me worry?" It should come as no surprise that most scientists take an intermediate position.
What do we know about global warming? For starters, the Earth is getting warmer. Over the past century, the average global temperature has risen 1[degrees]F. That is not a big deal--at least not vet. A related and vital question follows: Why is the Earth getting warmer? The answer is not simple. Greenhouse gases (such as carbon dioxide) contribute to the warming. Simultaneously, "natural causes" (e.g., changes in the intensity of the sun's rays) also play a role. Natural causes generated earlier cycles of global cooling and warming eons before the advent of industrialization. To compound the problem, there is a lack of hard data on the relative importance of natural causes versus human-generated factors.
Well, then, what can be--and should be--done? By definition, "natural causes" cannot be influenced by human actions. To state the matter simply, humans cannot tell the sun to stand still or even to "cool it." However, it is clear that C[O.sub.2] emissions are important contributors to greenhouse gases. Moreover, it is well known that burning fossil fuels generates these emissions. To compound the difficulty facing public policy, fossil fuels are the dominant source of energy in a modern economy. Those fuels primarily are petroleum, coal, and natural gas, which account for 85% of the energy used in the U.S.
The major C[O.sub.2] producers are factories, motor vehicles, and electric utilities. To state the matter boldly, as consumers or producers, we all are responsible for generating greenhouse gases via the burning of fossil fuels. So why doesn't the U.S. switch to other forms of energy? That course of action is not easy. For example, nuclear power does not generate any C[O.sub.2], but many of those most worried about global warming are strongly antinuclear. No nuclear power plant has been built in this country in more than three decades. There is a practical problem as well--the costs of constructing such a facility are much higher than a gas or coal-powered alternative.
How about newer, unconventional fuels? They now constitute a mere two percent of the U.S. energy supply. At present, none of the these sources is feasible commercially on a large scale. Solar energy is geographically limited to sunny regions and, even then, remains somewhat unreliable since it is beholden to the daily weather. Hydrogen--with current technology-uses a lot of electricity in its production cycle. Wind projects, meanwhile, are extremely controversial. Proposals for wind towers in Cape Cod, Mass., are hearing from environmentalists who worry that those modern windmills will destroy beautiful scenery as well as endanger wildlife, namely birds.
It is hard to avoid the cynical conclusion that the most unconventional energy sources are the most popular. The closer we actually get to using a new source, the more problematic it becomes. We can be more optimistic in the long run; on the basis of historical experience, we can expect that the prices of conventional energy will rise and that advances in technology will lower the costs of using newer, unconventional fuel sources. Nobody today can predict the timing of those crossover points with any confidence since none of us knows for sure what the global temperature of the future is going to be. …