In the balance

IN DRAMATIC FASHION - "Be Worried. Be Very Worried," read the cover line - a Time magazine story last week pronounced the debate on global warming over: ''Environmentalists and lawmakers spent years shouting at one another . . . but in the past five years or so, the serious debate has quietly ended."

Worse, the magazine declared, environmental catastrophe is already upon us. Cyclones pound Australia, ''drought-fueled blazes" ravage Indonesia, and ''the sodden wreckage of New Orleans continues to molder while the waters of the Atlantic gather themselves for a new hurricane season." When disasters ''hit this hard and come this fast-when the emergency becomes commonplace-something has gone grievously wrong. That something is global warming."

Unfortunately, there's one small problem with the claim that environmentalists and lawmakers, at long last, have come together on the once-divisive issue of global warming: They're still yelling at each other. Senator James Inhofe enraged greenies in 2003 by terming global warming a ''hoax," a statement he has not retracted, while last summer the Republican chairman of the House energy committee demanded an accounting of the data and funding sources of three top climate scientists-implying their studies were cooked. As if to prove the point that Americans aren't on the same page, all manner of conservative pundits mocked the Time piece: George Will said we should be less worried about big oil and big coal than ''big crusading journalism."

Yet in ignoring the likes of Inhofe and Will-and by shunning the small number of scientists who depart from the conventional view on warming-Time did exactly what many scientists have been begging journalists to do: It eschewed on-the-one-hand, on-the-other-hand reporting and threw its institutional weight behind the view of most scientists. ''The Time magazine statement is a fair representation of the vast consensus of the scientific community," writes Michael E. Mann, director of the Earth System Science Center at Penn State, in an e-mail.

As it happens, more and more environmentalists and climate scientists have been making the point that ''objective" journalists are doing as much as anyone (except maybe Hummer enthusiasts) to forestall action on global warming. And journalists are struggling to figure out whether that's a fair charge.

Al Gore, for instance, includes some trenchant journalism criticism in his forthcoming documentary on global warming, ''An Inconvenient Truth." Gore cites work by the UC-San Diego science historian Naomi Oreskes, who examined 928 abstracts of peer-reviewed articles on global warming published from 1993 to 2003. Oreskes found that precisely none of those articles questioned either that global warming exists or that humans contribute to it. Nevertheless, Gore laments, most news stories about global warming quote a skeptic.

And on the website realclimate.org - a resource for journalists and the public run by several prominent climate researchers-Penn State's Mann has argued that given how few dissenters there are among scientists on the global warming question, it makes as much sense to quote one of them as it would to grant ''the Flat Earth Society an equal say with NASA in the design of a new space satellite."

Realclimate.org also lays out the views its contributors say make up the foundation of modern climate science: First, the globe has warmed by 1.1 degrees Fahrenheit in the past 100 years (0.3 degrees Fahrenheit per decade over the past three decades). Second, people are causing ''at least the majority of this" increase. Third, the trend will continue if we keep pumping out greenhouse gases, like carbon dioxide. Fourth, it's a problem and we should do something about it. (These are also more or less the positions of the Intergovernmental Panel on Climate Change, a body of scientists created to summarize work in that field; the National Academy of Sciences; and the American Geophysical Union.)

Philip Elmer-DeWitt, Time's sciences editor, said the magazine listened to the arguments of people like Gore and Mann in deciding how to present its case. A Time/ABC News/Stanford University poll, he points out, found that 64 percent of Americans believe there is, among scientists, a lot of disagreement on this issue. Journalists share some of the blame for that, Elmer-DeWitt thinks. ''We are all trained to tell both 'sides,"' he says.

. . .

Those who defend the consensus view imply (or say outright) that anyone who departs from it is either a shill or a crank. But making things a bit dicey for us journalists who want to report the story in a nonideological way is the fact that a few evidently honest scientists still buck the consensus.

One is Richard S. Lindzen, the Alfred P. Sloan Professor of Atmospheric Science at MIT. He accepts the view that temperatures, and the carbon dioxide gas presence in the atmosphere, have risen. But he argues that correlation is not causation, and in a paper delivered at Yale last fall, he made the case that most climatologists ''fail to note that there are many sources of climate change, and that profound climate change occurred many times both before and after man appeared on the earth." The ''signal to noise" ratio is too low for us to know how big a role human-driven change plays in the recent warming trend, he thinks, and he finds no cause for alarm.

Of course, to some, I have just done humanity a disservice by quoting Lindzen. (I admit that's possible.) Indeed, science editors at different publications split on the question of how much space to give to such views. Scientific American seems to give especially short shrift to them; in an interview, editor John Rennie referred to dissenters as ''denialists" and said that to give them even one paragraph in a 10-paragraph article would be to exaggerate their importance.

Others, like Donald Kennedy, the editor of Science, offer more wiggle room. ''There ought to be some effort to report where the majority opinion lies," he says, ''but certainly the guys who have a different view ought not to be ignored completely." Lindzen, he adds, ''is a smart guy: He ought to be pressed with hard questions and listened to."

Yet citing both the consensus and the outlier critics can still sow confusion, as Discover magazine learned last fall. In the September issue, Discover ran one feature that opened by stating, ''few scientists of any political persuasion question the reality of human-induced global warming." In a separate interview, a senior meteorologist at Colorado State, William Gray, noted that he was ''skeptical as hell." Several readers wrote in to ask what they were supposed to make of the contradiction-or they charged Discover with exaggerating the degree of consensus. (The editor replied that Gray was part of a tiny minority.)

Time didn't quote any dissenters. That may be defensible, but the magazine then hurt its credibility by lumping together global warming trends (on which there is near-unanimous scientific consensus), human contributions to those trends (very high consensus), and the implications of these trends (much more of an open field). Last month, in dueling articles in Science, for example, researchers fought over whether global warming has led to an increase in the number of intense cyclones worldwide. Time skipped the debate and let readers think we've doomed ourselves to be hammered by more and more Katrinas.

In the end, the consensus that Time invokes seems like too much to hope for-on almost any subject. Which is a depressing thought, if the apocalyptic scenarios are right. For as the global-warming dissenters stick to their guns, vested interests sow confusion, and journalists try to figure out how to write about it all, the mercury rises. And as Michael Oppenheimer, a Princeton geoscientist, told Science last month: ''This is not an experiment you get to run twice."

Christopher Shea's column appears biweekly in Ideas. E-mail critical.faculties@verizon.net.