Global warming: man-made or natural?

• Author: Singer, S. Fred
• Position: Ecology - Critical essay

IN THE PAST FEW YEARS, there has been increasing concern about global climate change on the part of the media, politicians, and the public. It has been stimulated by the idea that human activities may influence global climate adversely and that, therefore, corrective action is required on the part of governments. Recent evidence suggests that this concern is misplaced. Human activities are not influencing the global climate in a perceptible way. Climate will continue to change, as it always has in the past, warming and cooling on different time scales and for different reasons, regardless of human action. I also would argue that--should it occur--a modest warming would be, on the whole, beneficial.

This is not to say that we do not face a serious dilemma. The problem, however, is political. Because of the mistaken idea that governments can--and must--do something about climate, pressures are building that have the potential to distort energy policies in a way that severely will damage national economies, decrease standards of living, and increase poverty. This misdirection of resources adversely will affect human health and welfare in industrialized nations, and even more in developing countries. Thus, it well could lead to increased social tensions within nations and conflict among them.

If not for this economic and political damage, one might consider the present concern about climate change nothing more than just another environmentalist fad, like the Alar apple scare or the global cooling fears of the 1970s. Yet, given that so much is at stake, it is essential that people better understand the issue.

The most fundamental question is scientific: Is the observed warming of the past 30 years due to natural causes or are human activities a main, or even a contributing, factor? At first glance, it is quite plausible that humans could be responsible for warming the climate. After all, the burning of fossil fuels to generate energy releases large quantities of carbon dioxide into the atmosphere. The C[O.sub.2] level has been increasing steadily since the beginning of the Industrial Revolution, and now is 35% higher than it was 200 years ago. Also, we know from direct measurements that C[O.sub.2] is a "greenhouse gas" which strongly absorbs infrared (heat) radiation. So, the idea that burning fossil fuels causes an enhanced "greenhouse effect" needs to be taken seriously--although in seeking to understand recent warming, we also have to consider the natural factors that regularly have warmed the climate prior to the Industrial Revolution and, indeed, before any human presence on Earth. After all, the geological record shows a persistent 1,500-year cycle of warming and cooling extending back at least 1,000,000 years.

In identifying the burning of fossil fuels as the chief cause of warming today, many politicians and environmental activists simply appeal to a so-called "scientific consensus." There are two things wrong with this. First, there is no such consensus. An increasing number of climate scientists are raising serious questions about the political rush to judgment on this issue. For example, the widely touted "consensus" of 2,500 scientists on the United Nations Intergovernmental Panel on Climate Change (IPCC) is an illusion, its shared Nobel Peace Prize with Al Gore notwithstanding. Most of the panelists have no scientific qualifications, and many of the others object to some part of the IPCC's report. The Associated Press reported that a mere 52 climate scientists contributed to the report's "Summary for Policymakers."

[ILLUSTRATION...