[10]Watch our video on how we fact-checked the hockey stick graph [10].

“Climate science has basically been at the receiving end of the best-funded, best-organized smear campaign by the wealthiest industry that the Earth has ever known—that’s the bottom line,” Mann told me when I visited him at his Penn State office last November. Near his desk, Mann keeps an actual hockey stick, signed by Middlebury College’s championship hockey team to show the school’s support for his work.
Things really heated up for Mann in late 2009, when more than 1,000 emails from him and other climate scientists were lifted from a server at the Climatic Research Unit [22] (CRU) of the UK’s University of East Anglia, the world’s leading research institution focused on climate change. The emails offered a window into the climate-science bunker, with a view of Mann and his fellow researchers growing increasingly defensive. One scientist wrote[23] that he was “tempted to beat the crap out of” a skeptic at the libertarian Cato Institute. Another joked that the way to deal with skeptics was “continuing to publish quality work in quality journals (or calling in a Mafia hit).” Scientists suggested that they would rather destroy data than provide them to their critics. They also discussed using “tricks” in their research, debated how to frame uncertainties in some of their data, and attempted to control access to peer-reviewed journals.
 [24]Click here to see our timeline of the Climategate scandal[25].
Within days, the heist—soon dubbed “Climategate [26]“—was all over the news. Glenn Beck called it [27] a “potentially major scandal”; Fox News crowed [28] that the emails “undercut the whole scientific claim for man’s impact on global warming.” Rep. James Sensenbrenner (R-Wis.) decried [29] (PDF) them as evidence of “scientific fascism.”
The immediate impact on public opinion was dramatic. A poll by Yale and George Mason University [30] (GMU) found that in November 2008, 71 percent of respondents agreed that the planet is warming (PDF). Five weeks after Climategate, only 57 percent believed it. The emails, said a Yale report [31] (PDF), had “a significant effect on public beliefs in global warming and trust in scientists.”

IF A SINGLE PERSON CAN BE credited with setting the stage for Climategate, it’s Stephen McIntyre, the retired mining consultant behind the popular skeptic blog Climate Audit [32]. Over the past decade, McIntyre has built a reputation for finding methodological errors—some real, some perceived—in climate studies. The Wall Street Journal heralded McIntyre [33] as “global warming’s most dangerous apostate.”
Indeed, McIntyre has made goading scientists—particularly Mann—close to a full-time job. Like Mann, McIntyre is genial in interviews, but on his blog, his tone toward the scientists targeted by his audits ranges from inquisitive to openly hostile.
The 63-year-old squash enthusiast from Toronto made his money in mining. He has also consulted for the Canadian oil and gas exploration company CGX Energy [34]. He says his mining ties don’t affect his views on climate change and insists that his prolific blogging on the topic has not benefited him financially—rather, it’s taken time away from more profitable business.

So how much of a nuisance was McIntyre? Consider his attempts to procure the crucial global temperature data sets that are jointly held by the CRU and the UK’s Met Office Hadley Centre [75]. McIntyre dogged the CRU for access to them for years, a campaign that escalated over the course of 2009. The CRU repeatedly turned down these requests, arguing that granting them would violate agreements over data its partners had collected. Then, in June 2009, McIntyre found out that the CRU had provided the very information he had been requesting to a scientist at Georgia Institute of Technology [76]. In response, McIntyre penned [77] an angry screed onClimate Audit. In just the last week of July 2009, CRU received [78] 58 FOIA requests from McIntyre and others [79] (PDF) affiliated with Climate Audit. CRU head Phil Jones argued that responding to these requests was creating an unmanageable burden.
Emails from this period show the scientists lashing out against McIntyre. He is referred to as a “bozo [80]” and “a playground bully [81].” McIntyre clearly gets a rise out of irking scientists, whom he frequently refers to as “the Team [82]“—another play on the hockey-stick metaphor. He likes to “tease these guys and kind of make fun of them,” he says, and their evident aggravation at his inquiries only egged him on. “I think it was a mistake for them to in effect adopt a fatwa against Climate Audit,” says McIntyre.
McIntyre’s latest requests for both the raw CRU data and the email correspondence between scientists about those data were formally denied on November 13, 2009. Four days later, a massive bundle of files named FOIA.zip was anonymously posted on several prominent skeptic blogs and RealClimate. In it were years’ worth of the climate scientists’ email exchanges. McIntyre says he doesn’t know who posted the file but adds that the timing is one of several “really strange coincidences” surrounding the emails, “if it is a coincidence.” It was also, notably, just days before the start of the Copenhagen climate talks, which many hoped would result in a new global deal for regulating greenhouse gas emissions.

SOMETIME ON OR AFTER November 12, more than 1,000 emails between climate scientists and 3,587 other documents, including raw data and computer code, were copied from the CRU server. The files were posted online, with duplicates posted to several other servers around the world. At 7:24 a.m. EST [83], a link to the files appeared in a comment [84] on McIntyre’s Climate Audit.
Around 7:30 a.m. that day, Gavin Schmidt, a climate modeler at NASA and cofounder with Mann of RealClimate, awoke to find his site disabled. He attempted to log in and failed. When he finally got in as the administrator, he found that the files had been uploaded to the site. At that very moment, the hacker was using a ghost administrator account to try to create a blog post that linked to the files and quoted some portions of the emails.
Schmidt recalls, “I was going, ‘What’s this? Oh God, this is some emails. I wrote some of these emails.'” Schmidt emailed Mann, Jones, and other scientists whose emails were included.

AMERICAN SKEPTICISM about the danger of global warming was already on the rise when Climategate hit the news in 2009, but the story made independents (and some Democrats) far more likely to answer yes to the question: Do the media exaggerate the seriousness of climate change?

A YEAR AND A HALF LATER, the question of who stole the emails and released them has never been answered. Mosher and other climate skeptics maintain that it was likely an inside job, carried out by someone at the University of East Anglia who wanted problematic science exposed. The CRU, on the other hand, maintains that it was the work of someone outside of the university—a “very professional job,” says Trevor Davies [109], pro-vice chancellor for research at East Anglia and the former head of the CRU.
Meanwhile, the university hasn’t disclosed the evidence for its assertion, nor has the Norfolk Constabulary [110], the local police department responsible for the official ongoing investigation. McIntyre says British counterterrorism officers have contacted him and other bloggers about the case, but as far as he knows, nothing has ever come of the inquiry.
It’s clear that the hacker was at least familiar with the climate-science debate; he knew enough to search through the hacked emails using keywords like “Mann,” “hockey stick,” and “Phil Jones” and to sort them accordingly. A source close to the CRU explains that the unit’s security wasn’t very tight—its server is separate from the rest of the university’s.
That said, the cybersecurity experts I talked to noted that a hack like this would have required some sophisticated skills. Once the hacker breached the server, he still would have had to find his way into the system administrator’s account, a feat that could have required special software to access the password. Then, in order to remain anonymous when posting the emails online, he would have had to scan the internet for nonsecure servers to work from—this would have allowed him to cover his own IP address. The hacker also used servers in multiple countries, making it even more difficult to trace his whereabouts.
It later became clear that CRU was not the only target [111]. In the fall of 2009, unknown parties posing as network technicians attempted to break into the office of a climate scientist at the University of Victoria in British Columbia. There were also attempts to gain access to servers at the Canadian Centre for Climate Modelling and Analysis. According to a source within the institution, there were also unsuccessful attempts to breach the server at the National Center for Atmospheric Research in Colorado. A US diplomatic cable that WikiLeaks[112] released in late 2010 also revealed “evidence of an attempt to gain unauthorized entry to computer systems” belonging to the State Department’s climate bureau in 2009. The cable warned that “as negotiations on the subject of climate change continue, it is probable intrusion attempts such as this will persist.”

SO DID THE SCIENTISTS DO something more diabolical than gripe about critics and fret over how their research would be interpreted? Not according to seven separate inquiries on the subject, each of which found that the researchers’ work was not in question—though several concluded that their behavior was. An independent probe organized by the University of East Anglia [113] (PDF) found that some had turned down “reasonable requests for information” and had, at times, been “unhelpful and defensive.” It noted “a consistent pattern of failing to display the proper degree of openness.”
But none of the exonerations mattered: The scientists had lost control of the narrative. The percentage of people who believe that the world is warming has fallen 14 points from its 2008 high, according to polling [31] (PDF). Gallup’s annual poll [114] in 2010 found that 48 percent of Americans said they believe that fears of global warming “are generally exaggerated”—the highest figure since pollsters began asking that question in 1997.
Most significant, however, has been the long-term hardening of the political divide on the issue. In 1997, the percentage of Republicans and Democrats who believed in climate change was nearly the same—47 percent and 46 percent, respectively. By March 2010, 66 percent of Democrats and only 31 percent of Republicans agreed that global warming was already occurring. Half of the new House GOP members [115] flatly deny that the planet is warming, and only four say [116] they accept the science of climate change.
Rep. Darrell Issa (R-Calif.), the new head of the House Committee on Oversight and Government Reform [117] (PDF), last fall outlined plans to hold hearings on the “Politicization of Science,” focused largely on Climategate. Rep. Ralph Hall [118] (R-Texas), the new chairman of the House Committee on Science, Space, and Technology, has already said that he plans to look into “the global warming or global freezing.” The vice chairman of the same committee, Rep. James Sensenbrenner (R-Wis.), has accused climate scientists of a “massive international scientific fraud [119] (PDF).” Virginia’s attorney general, Ken Cuccinelli, has subpoenaed [120] (PDF) records from Mann’s time at the University of Virginia in an attempt to prove that he committed “fraud.” Congressional Republicans are also using Climategate as fodder [121] in their fight to bar the Environmental Protection Agency from regulating greenhouse gas emissions.