Quotes of the Day

The controversy over e-mails stolen from global-warming researchers at the Climatic Research Unit (CRU) at Britain's University of East Anglia has become so divisive that there is even disagreement over what to call it.

Skeptics of global warming, who have long considered climate change a fraud, refer to the incident as "Climategate," with obvious intimations of scandal and cover-up. Advocates of action on warming call it "Swifthack," a reference to the 2004 character attacks on presidential candidate Senator John Kerry by the group then known as Swift Boat Veterans for Truth — in other words, an invented scandal propagated by conservatives and the media that does nothing to change the scientific case for climate change.

The truth is that the e-mails, while unseemly, do little to change the overwhelming scientific consensus on the reality of man-made climate change. But they do hand a powerful political card to skeptics at the start of perhaps the most important environmental summit in history. Still don't know what to make of it? If you're struggling to untangle the details of the e-mail controversy, here are five key things you need to know:

1. How were the e-mails leaked? On Nov. 17, administrators of the website RealClimate, a blog about climate science written by top researchers, discovered that unknown hackers were attempting to upload onto the blog more than 1,000 e-mails apparently sent by and to scientists at University of East Anglia's CRU. The CRU is one of the most important climate-research centers in the world, and one of a handful of scientific agencies that keep the global temperature records used in most major climate models. Officials at East Anglia soon confirmed that electronic theft had occurred and that the e-mails were genuine. By the end of the week, they were widely available on the Internet.

In early December, the e-mail controversy was still burning up the blogosphere, as international negotiators gathered at the Copenhagen climate summit. The head of the CRU and author of several incriminating e-mails, environmental scientist Phil Jones, has stepped down temporarily from his post while University of East Anglia conducts an independent inquiry into the e-mail controversy. The investigation will be led by Muir Russell, a prominent Scottish academic and civil servant. Meanwhile, Pennsylvania State University (PSU) announced it would conduct its own inquiry into the e-mails, after PSU climatologist Michael Mann also emerged as an author of e-mails that were central to the controversy.

2. What exactly do the e-mails say? The more than 1,000 e-mails dating back some 13 years contain a range of information — everything from the mundanities of climate-data collection to comments on international scientific politics to strongly worded criticisms of research by climate-change doubters. It is mainly the last point that has skeptics crying foul. In one e-mail, sent to Mann from Jones, the topic is a pair of papers that criticize the case for man-made global warming; Jones wrote that he and his colleagues would be sure to keep the papers out of consideration for the forthcoming climate assessment by the Intergovernmental Panel on Climate Change (IPCC), "even if we have to redefine what the peer-review literature is."

In another e-mail exchange, Mann and Jones discuss ways to pressure an academic journal Climate Research to stop publishing submissions from climate skeptics, with Mann suggesting that they consider encouraging colleagues not to submit papers to the journal until it changes its editorial stance. Jones also wrote repeatedly about rebuffing requests by climate skeptics for raw temperature data from CRU, and seemingly encourages his colleagues to delete e-mails concerning a Freedom of Information request for the data.

In other e-mails, scientists appear to have trouble reconciling recent temperature data with the warming expected from climate models. And overall, the correspondence evinces climate scientists' outright scorn for global-warming skeptics; in one message, Ben Santer, a researcher from Lawrence Livermore Laboratory offers — presumably in jest — to "beat the crap out of" a leading skeptic.

Perhaps most damningly, in an e-mail from 1999, Jones refers to one of Mann's studies from the prominent journal Nature in a discussion of his own data: "I've just completed Mike's Nature trick of adding in the real temps to each series for the last 20 years (i.e. from 1981 onwards) and from 1961 for Keith's to hide the decline." (By the "decline," Jones is presumably referring to the fact that temperature data reconstructed from tree-ring density — a common way to estimate global temperatures before the widespread use of the thermometer — diverges somewhat from recorded temperatures after 1960.)

3. How have the e-mails been interpreted? To global-warming doubters, the CRU e-mails are the new Pentagon Papers, proof that the powers that be — in this case, international climate scientists — are engaged in outright fraud and were exposed only by a brave whistle-blower.

Many skeptics argue that the case for man-made global warming has been essentially undone, and that before the world goes any further in considering action to control greenhouse-gas emissions, all scientific evidence for warming must be reevaluated. Jones' e-mail about Mann's "trick" appears to indicate that climate researchers have been actively manipulating scientific data to better fit their models on climate change, while other e-mails seemingly confirm what skeptics had long suspected — that the globe in recent years wasn't warming as fast as theories on climate change had assumed. Most of all, the tone of the CRU e-mails suggests that climate scientists are mired in groupthink, utterly resistant to skeptical viewpoints and willing to use pressure to silence dissenters of the global-warming mainstream. In other words, the e-mails showed what Republican Representative Jim Sensenbrenner called "scientific fascism," which he argues is "at worst ... junk science" and "part of an international scientific fraud."

Climate scientists are taking the e-mail controversy seriously. Inquiries are under way at University of East Anglia and Penn State, and IPCC head Rajendra Pachauri has said that the controversy cannot be "swept under the carpet," promising also that the U.N. body will examine the e-mails independently. But global-warming skeptics have already declared victory. "It appears from the details of the scandal that there is no relationship whatsoever between human activities and climate change," said Mohammed Al-Sabban, Saudi Arabia's lead climate negotiator, according to the BBC.

4. Do the e-mails weaken the scientific case for global warming? Put it this way: when it comes to climate-science analysis from the representative of the world's biggest oil-producing state, it's wise to be suspicious. In the weeks since the e-mails first became public, many climate scientists and policy experts have looked through them, and they report that the correspondence does not contradict the overwhelming scientific consensus on global warming, which has been decades in the making. "The content of the stolen e-mails has no impact whatsoever on our overall understanding that human activity is driving dangerous levels of global warming," wrote 25 leading U.S. scientists in a letter to Congress on Dec. 4. "The body of evidence that underlies our understanding of human-caused global warming remains robust."

According to PSU's Mann, that statistical "trick" that Jones refers to in one e-mail — which has been trumpeted by skeptics — simply referred to the replacing of proxy temperature data from tree rings in recent years with more accurate data from air temperatures. It's an analytical technique that has been openly discussed in scientific journals for over a decade — hardly the stuff of conspiracy.

As for Mann and Jones' apparent effort to punish the journal Climate Research, the paper that ignited his indignation is a 2003 study that turned out to be underwritten by the American Petroleum Institute. Eventually half the editorial board of the journal quit in protest. And even if CRU's climate data turns out to have some holes, the group is only one of four major agencies, including NASA, that contribute temperature data to major climate models — and CRU's data largely matches up with the others'.

It's true that the e-mails reveal CRU climate scientists were dismissive of skeptics, often in harsh terms, but that's not unusual for scientists. Science is a rough arena, as anyone who has ever survived a doctoral examination knows, and scientists aren't shy about attacking ideas they believe are wrong — especially in private communication. Still, Jones et al. could have been more open and accepting of their critics, and if it turns out that e-mails were deleted in response to the Freedom of Information request for data, heads should roll. (Jones maintains that no e-mails or documents were deleted.)

Ultimately, though, we need to place Climategate/Swifthack in its proper context: amidst a decades-long effort by the fossil-fuel industry and other climate skeptics to undercut global-warming research — often by means that are far more nefarious than anything that appears in the CRU e-mails. George W. Bush's Administration attempted to censor NASA climatologist James Hansen, while the fossil-fuel industry group the Global Climate Coalition ignored its own scientists as it spread doubt about man-made global warming. That list of wrongdoing goes on. One of the main skeptic groups promoting the e-mail controversy, the Nongovernmental International Panel on Climate Change, was recently revealed to have links to the energy company Exxon-Mobil, which has long funded climate-change deniers. "This is being used to confuse the public," says blogger James Hoggan, whose new book Climate Cover-Up details Exxon-Mobil's campaign. "This is not a legitimate scientific issue."

5. Will the controversy derail efforts to curb warming? Although the e-mails have no bearing on the scientific case for climate change, they'll likely have a major political impact. At the very moment when countries around the world — including the U.S. — seem poised, finally, to begin to control greenhouse-gas emissions, the controversy created by the e-mails allows skeptics to roll some of the momentum back, at least by injecting doubt among a confused public.

That strategy might be working. A survey published on Dec. 3 by the conservative-leaning polling group Rasmussen Reports found that 52% of Americans polled believe there remains significant disagreement within the scientific community over global warming, and that 84% of Americans believe it is at least somewhat likely that some scientists have falsified data to support their theories on global warming. Unfortunately, scientific truth matters less than public perception — a doubtful public is that much less likely to support tough caps on greenhouse-gas emissions.

In the aftermath of the e-mails, climate scientists and advocates will need to rethink how they engage with critics. Judith Curry, an atmospheric scientist at Georgia Tech, wrote in a much discussed blog post that researchers need to make climate data much more open and transparent, and that scientists need to be wary of falling into what she calls "climate tribalism." She argues that mainstream climate scientists are now resorting to the same smear tactics that skeptics have long used against climate scientists — something Michael Shellenberger and Ted Nordhaus of the think tank Breakthrough Institute have called "climate McCarthyism."

"Heavy-handed efforts to narrow the scientific debate have seriously damaged the credibility of climate science," says Nordhaus, whose work has come under sharp criticism from many environmentalists. "Environmental advocates and sympathetic scientists have set back efforts to address global warming."

And yet climate scientists cannot be expected to debate with a skeptical monolith. While the largely conservative doubters of man-made climate change are a small minority, they remain immovable. What scientists view as healthy debate, critics tend to see as evidence that the scientific case is still open — and the American public, large portions of which are all but scientifically illiterate, are not equipped to make the distinction.

Despite the e-mail controversy, however, momentum on climate-change action is still building. Environmentalists are feeling increasingly hopeful that the Copenhagen summit could produce concrete action on emissions cuts, with U.S. President Barack Obama changing his schedule to arrive on the final day of negotiations. "The clock has ticked down to zero," said the U.N.'s climate chief Yvo de Boer on the first day of the talks. "After two years of negotiation, the time has come to deliver." There's nothing invented about that urgency.

• Bryan Walsh