In science, hypotheses become accepted truths one experiment, one study at a time. Initial doubts become so small, and the doubters so few, that a new scientific “truth” emerges. Even though these “truths” are never fully proven—be it about evolution, relativity, or even gravity—the gradual whittling away of doubt eventually compels scientists to call in the jury and declare the matter settled. Such is the case for global warming and its link to human activity.

In 1988 James Hansen, a respected NASA scientist, testified before the Senate Committee on Energy & Natural Resources, saying he was “99 percent certain” that global warming was real and that it was linked to human activity. Two years later the Intergovernmental Panel on Climate Change (IPCC), a United Nations’ body initially backed by 175 scientists in 25 countries, convened to address global warming and declared that human activity was contributing to a warming planet. In the 17 years since the IPCC was formed, the group has grown to include more than 2,000 scientists in 100 nations, and global temperatures have continued to rise, leading to the hottest years ever recorded.

Increased temperatures coincide with the rising levels of carbon dioxide from the burning of fossil fuels and from worldwide deforestation. In 2003 the American Geophysical Union, an international scientific research group with more than 41,000 members, declared that “Human activities are increasingly altering the earth’s climate. These effects add to natural influences that have been present over earth’s history. Scientific evidence strongly indicates that natural influences cannot explain the rapid increase in global near-surface temperatures observed during the second half of the 20th century.” Similar declarations came from the American Meteorological Society, the American Association for the Advancement of Science, and the National Academy of Sciences.

The conclusions underscore the research of Naomi Oreskes, a science historian at the University of California at San Diego, who reviewed 928 abstracts of articles on global climate change published in scientific journals between 1993 and 2003 and could not find a single one that challenged the scientific consensus that human-caused global warming is real. “There have been arguments to the contrary,” she wrote in a 2004 editorial in The Washington Post, “but they are not to be found in scientific literature, which is where scientific debates are properly adjudicated.” The overwhelming agreement echoed the 1997 conclusions of D. James Baker, the former administrator of the National Oceanic and Atmospheric Administration, who declared, “There is better scientific consensus on this than on any other issue I know—except maybe Newton’s second law of dynamics.”

“The time to call the jury in for a clear verdict has long passed” proclaimed Sir David King, science adviser to Tony Blair, in a 2002 speech.

Controversy Feeds Disbelief

Americans could be forgiven for not knowing how uncontroversial this issue is among the vast majority of scientists. Even as Arctic ice and permafrost begin to melt, resulting in slumping houses and new global shipping lanes, and the world’s leading scientists agree these phenomena are linked to human activity, American readers, viewers and listeners continue to get the impression that the jury will be deliberating well into the future.

“Context and Controversy: Global Warming Coverage”
– Jessica Durfee and Julia Corbett
“In the case of global warming, the media have more often than not overplayed the level of uncertainty about global climate change,” wrote Julia Corbett and Jessica Durfee in a 2004 article in Science Communication. The reason, the authors write, is largely because of traditional journalistic balance. “The result of the routine media practice of quoting conflicting ‘sides,’” wrote Corbett and Durfee, is “giving equal weight to fringe and nonscientists as much as scientists … even though the majority of evidence or opinion may fall clearly to one side.”

Another factor, writes Dominique Brossard and colleagues in a 2004 study published in Mass Communication and Society, is the American media’s inclination to generate stories with drama and conflict. “American media actively constructed narratives about global warming to maintain public interest,” they wrote. “In developing their narratives, they may choose to frame stories in a particular way … ignoring others or simply reporting facts or perspectives more interesting or challenging than others …. The journalistic tendency to draw in discordant opinions in a story can lend strength to a viewpoint that may have very little credence in the scientific community at large.”

“Disinformation, Financial Pressures, and Misplaced Balance”

– Ross Gelbspan
Remaining skeptics do include a few especially cautious scientists who point out, for example, that the earth might be in a natural warming trend so it is therefore impossible to determine how much of the problem is human-caused. Many of the skeptics, however, are supported by industry-backed groups such as the Greening Earth Society and the Global Climate Coalition. Ross Gelbspan, a former Boston Globe editor and reporter who has written two books about climate change, argues that these groups are part of a “carbon lobby” whose central purpose is to raise doubts on the issue through public relations campaigns. Gelbspan quoted industry documents aiming to “reposition global warming as theory rather than fact.”

“The handful of carbon, natural gas, and oil interests have been handed a megaphone that carry their voice farther and louder than it does in strictly scientific circles,” says Bud Ward, a longtime reporter on the environment who remembers similar debates over the ozone hole starting in 1976. “Public perceptions are being torqued toward a greater uncertainty than actually exists in a responsible scientific community.”

Equally influential, in some cases, are nonscientists, including the novelist Michael Crichton, whose “State of Fear” decries environmental extremism and who writes in an author’s note, “We know astonishingly little about every aspect of the environment, from its past history, to its present state, to how to conserve and protect it. In every debate, all sides overstate the extent of existing knowledge and its degree of certainty.” Crichton, who declares that “everyone has an agenda, except me,” has nevertheless seen fit to testify before the U.S. House and Senate at the invitation of conservative legislators who continue to sow doubt on the issue among the general public.

The Dangers of Balance

The weight many journalists give to such views, in insisting on balance but not on putting it within a broader scientific and political context, appears to be at the heart of the confusion among Americans, who may understandably determine from the “dueling experts” that nothing can be concluded and thus that action is not yet warranted. “The message of the traditional balanced account may be, ‘Well, who knows what’s really true?’,” wrote Corbett and Durfee.

Ward agrees that “the old journalism 101 thing about balance” is creating a problem in the coverage of climate change. “Balance in some cases can be the enemy of accuracy,” he says. “I’m all for balance in a gubernatorial campaign, a presidential campaign, policy stories. But science isn’t determined by a popularity contest. We went through this for how long with tobacco? Certainly this is not the first time we’ve seen the mistaken application of balance.”

But the U.S. media may be inching closer to its own verdict, one more aligned with scientists. Seth Borenstein, who covers science and the environment for Knight Ridder’s 32 daily papers, said he’s noticed that in the past few years environmental reporters have reached a consensus for how to cover global warming that still adheres to the American journalistic ethic of including disputing views, but puts those views into a clear context: “Most of the people you talk to are legitimate, mainstream scientists,” explained Borenstein. “You put a paragraph in saying ‘There are a minority of scientists skeptical, they say this, but the vast, overwhelming majority of scientists disregard them.’”

In April and May 2005, The New Yorker published Elizabeth Kolbert’s three-part series, “The Climate of Man,” which documents changes to the planet and concludes by asking, “As the effects of global warming become more and more apparent, will we react by finally fashioning a global response? Or will we retreat into ever narrower and more destructive forms of self-interest? It may seem impossible to imagine that a technologically advanced society could choose, in essence, to destroy itself, but that is what we are now in the process of doing.”

In the months following Kolbert’s series, The Washington Post and The New York Times published major takeouts on global warming in the Arctic, with the Times’s Andrew Revkin writing in “The Big Melt” series on October 25th, “many … scientists have concluded that the momentum behind human-caused warming, combined with the region’s tendency to amplify change, has put the familiar Arctic past the point of no return.” An informal survey of articles published in 2004 and 2005 in American newspapers also suggests less uncertainty on the issue than in previous years. One representative headline from The Seattle Times declared, “Scientists overwhelmingly agree: The earth is getting warmer at an alarming pace, and humans are the cause no matter what the skeptics say.”

Reports continue, however, of a reluctance to tackle the issue in all its gravity, both in the press and in popular culture. The summer documentary hit “March of the Penguins,” which intimately documents the migration and mating habits of penguins in Antarctica, does not once mention that the creatures’ habitat may melt away. Luc Jacquet, the French biologist and director of the film, told National Geographic News, “It’s obvious that global warming has an impact on the reproduction of the penguins. But much of public opinion appears insensitive to the dangers of global warming. We have to find other ways to communicate to people about it, not just lecture them.”

In cases of Americans’ reluctance to confront this situation, the issue goes deeper than efforts by the “carbon lobby,” or journalistic models of balance, to something far deeper. Valerie Brown, a freelance journalist who has written about global warming, said she worries that as they find out more about the issue, “people will just get more anxious and cocoon even more while the world is going to hell in a handbasket.”

“There’s not a clear-cut view in society’s mind about what can be done about it,” says Ward. “Is it bigger than both of us? Is this something that we human beings just can’t affect? It’s not like CFC’s [chlorofluorocarbons, released in aerosol sprays], where you can just take them off the market. It’s not clear that there’s a counterpart solution. There’s the difficulty of not finding a silver bullet.

“And that,” Ward says, “basically invites denial.”

Sandy Tolan, a 1993 Nieman Fellow, directs the Project on International Reporting at the Graduate School of Journalism at the University of California, Berkeley. He is cofounder of Homelands Productions, a contributor to National Public Radio, and author of “The Lemon Tree: An Arab, A Jew, and the Heart of the Middle East,” to be published by Bloomsbury in May 2006. Alexandra Berzon is a freelance journalist and a graduate student of journalism at the University of California, Berkeley.

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