December 19, 2007
A Follow Up on Media Coverage and Climate Change
Posted to Author: Pielke Jr., R. | Climate Change | Journalism, Science & Environment
Last week I asked a few reporters and scholars why it is that a major paper in Nature last week on hurricanes and global warming received almost no media coverage whereas another paper released last summer received quite a bit more. Andy Revkin raised the issue on his blog which stimulated many more responses. With this post Iíd like to report back on what Iíve heard, and what Iíve concluded, at least tentatively, on the role of the media in the climate debate.
First, there are a wide range of explanations for the differences in media coverage of the two papers. Here is a summary of what I heard (warning: not all explanations are consistent with each other):
*The media is biased toward sensational stories, and Vecchi/Soden was not sensational.
One question I asked of several people is the apparent paradox between the recent "balance as bias" thesis which holds that skeptical voices are given too much play in debate over climate change with the claims from several people I spoke to that the media tends to favor alarming stories in the climate debate. The best answer I got to this came from a reporter:
In general, news coverage favors the sensational rather than the mundane. For example, there were tons of stories this year on the arctic sea ice extent. Next year, if the sea ice doesnít set a record, the coverage will be less by orders of magnitude.
To test this out the hypothesis of a general bias against skeptical voices I searched Google News for references (2004 to present) to "climate change" and "hurricanes" for both "William Gray" who advocates no discernible effect of global warming on hurricanes and "Kerry Emanuel" who advocates a very strong effect. There were 268 stories quoting Emanuel and 297 quoting Gray. This would suggest that, on the hurricane issue at least, there is no indication that the media has disfavored skeptical voices. These data donít say much about the media favoring the sensational, as Grayís presence in news stories might just be "balance" in a sensationalized story. More work would need to be done to say anything on that.
Looking to the academic literature Mullainathan and Shleifer (2002, full cite and link below) provide the best piece of research that I have seen on media bias. They focus on ideological biases and also what they call "spin." which is the same thing as favoring (or creating) sensational stories as suggested above. They suggest that (emphasis added):
. . . competition is an important argument for free press: despite the ideological biases of individual news suppliers, the truth comes out through competition. We show that, with Bayesian readers, this is indeed the case: competition undoes the biases from ideology. With readers who are categorical thinkers, however, the consequences of competition are more complex. We show that, in the absence of ideology, competition actually reinforces the adverse effects of spin on accuracy. Not only do the media outlets bias news reporting, but the stories reinforce each other. As each paper spins stories, it increases the incentives of later outlets to spin. This piling on of stories means non-ideological competition worsens the bias of spin. Moreover, spin can exacerbate the influence of one-sided ideology. When the first news outlet that uncovers the story is ideological and later ones are not, the first one sets the tone and later ones reinforce this spin. This can explain why and how inside sources leak information to news outlets: their principal motivation is to control how the story is eventually spun.
If these findings are anywhere close to the mark, then they offer a powerful counterargument to the "balance as bias" thesis. The climate issue is characterized by a wide range of ideological perspectives, and it seems hard to justify why any of those perspectives should not be represented by the media. That means reporting on a wide range of political perspectives and the justifications for those views offered by those holding those perspectives, even if the reporter, or the vast majority of scientists or other groups, happens to disagree with either the politics or justifications. Where there is diversity balance is not bias, but bias is bias.
S. Mullainathan and A. Shleifer. 2002. Media Bias, NBER WORKING PAPER SERIES, Working Paper 9295 NATIONAL BUREAU OF ECONOMIC RESEARCH, 1050 Massachusetts Avenue, Cambridge, MA 02138, October 2002, © 2002 by Sendhil Mullainathan and Andrei Shleifer. http://www.nber.org/papers/w9295
For further reading, see this New York Times book review on media bias by Richard Posner.
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