A new study published in the journal Global Environmental Change (see here for a press report) argues that, by adhering to the journalistic standard of balance when reporting on global warming, prestigious American newspapers have introduced an "informational bias" into public discussion of the issue. The trouble is that the analysis fails to take into account why we have newspapers in the first place. The authors are essentially making a case for censorship in favor of special interests.<?xml:namespace prefix = u1 /> <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
The authors, from UC Santa Cruz and <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />American University, analyzed 3543 news articles that appeared between 1988 and 2002 in the pages of the New York Times, the Washington Post, the Los Angeles Times, and the Wall Street Journal. They compared the "balance" in these articles between arguments advanced by scientists who say global warming is a problem and those who are more skeptical with the "managerial scientific discourse of groups such as the IPCC." They claim that there is a disconnect between the two that is misinforming the public over the state of the science. They defined "balanced coverage" as "accounts [that] gave 'roughly equal attention' to the view that humans were contributing to global warming, and the other view that exclusively natural fluctuations could explain the earth's temperature increase."
This is a crude distinction. Very few scientists—even the scientists the authors imply are helping the media misinform the public—dispute the idea that anthropogenic contributions are warming the atmosphere to some degree. Prominent "skeptic" Patrick J. Michaels of the University of Virginia, for instance, is on record as saying that humans are warming the planet, but we know that the total increase in temperature will be small (see here, for example). On the other hand, there are few scientists who would argue that natural fluctuations do not play an important role in the planet's temperature. The IPCC itself, for instance, says,
"There is an increasing realization that natural circulation patterns such as [El Nino-Southern Oscillation] and [North Atlantic Oscillation] play a fundamental role in global climate science and its interannual and longer-term variability." (Climate Change 2001: The Scientific Basis, p.51)
It is the interplay between human effects and natural variability that is the meat of the scientific debate, not some crude opposition between extremes.
The latest edition of the US Global Change Research Program's publication "Our Changing Planet", for instance, contains news of the following research, as yet unpublished and therefore at a very early stage in the scientific process:
"Comparison of index trends in observations and model simulations shows that North American temperature changes from 1950 to 1999 were unlikely to be due only to natural climate variations. Observed trends over this period are consistent with simulations that include anthropogenic forcing from increasing atmospheric greenhouse gases and sulfate aerosols. However, most of the observed warming from 1900 to 1949 was likely due to natural climate variation." (p. 47)
Note the guarded language -- "unlikely to be due only to natural climate variations." This squares with the language in the National Academy of Sciences report on the state of the science in 2001, which took pains to point out:
"Because of the large and still uncertain level of natural variability inherent in the climate record and the uncertainties in the time histories of the various forcing agents (and particularly aerosols), a causal linkage between the buildup of greenhouse gases in the atmosphere and the observed climate changes during the 20th century cannot be unequivocally established. The fact that the magnitude of the observed warming is large in comparison to natural variability as simulated in climate models is suggestive of such a linkage, but it does not constitute proof of one because the model simulations could be deficient in natural variability on the decadal to century time scale. The warming that has been estimated to have occurred in response to the buildup of greenhouse gases in the atmosphere is somewhat greater than the observed warming. At least some of this excess warming has been offset by the cooling effect of sulfate aerosols, and in any case one should not necessarily expect an exact correspondence because of the presence of natural variability." (p. 17)
It should be clear, then, that the scientific debate is nowhere near as clear cut as the authors would like it to be. Models may well be incomplete. Because of the uncertainties involved—admitted as much by all reputable scientists—journalists have a duty to present those significant uncertainties to their readers.
Yet a greater misconception occurs when the authors analyze the media reports in another manner that they relate to science. They contend that "the scientific community has reached general consensus that immediate and mandatory actions are necessary to combat global warming." With respect, this is a political rather than a scientific statement. Scientists, thankfully, cannot mandate action. Science can only inform us of potential options. In a democracy, it is the people's choice as to what options they select. Make no mistake, in this field there are many competing options. For example, a strategy aimed at adapting to a changing climate rather than attempting to stop it from changing is a valid option. If the cost-benefit mix of the former option is better for society than that of the latter, then it would be irrational to choose the latter.
So when the authors argue that newspapers are failing the public when they fail to reflect the supposed views of the scientific community about action, then the authors are failing to see the big picture. One of the roles of a free press in a democracy is to inform the public about policy options on which they have a voice. Restricting coverage of options based on the say so of any one group—whether it is scientists, industry, or a church—is to sacrifice a free press on the altar of special interests. Journalistic standards are designed to protect us from that danger. Scientists, concerned or otherwise, are not aristocrats. They should be wary of those who treat them as such.