n historical climate readings in order to make a more dramatic point. Yet numerous other reconstructions of historical temperature records made since Mann’s graph have also shown a dramatic uptick in the 20th century, and a 2006 assessment from the National Academy of Sciences concluded (PDF) that while Mann’s methodology wasn’t perfect, the story the chart told was accurate.
Yet global warming skeptics have made the graph exhibit A in their cause. Congressional hearings have focused on it, and it has been the impetus for multiple critical books and blog posts. Skeptics have dismissed the graph as “little more than paleo-phrenology” and claimed that “Mann-made warming is real, while man-made warming remains at best a theory, more likely a hypothesis.”
And Mann himself has become a target. Virginia’s crusading Republican attorney general has suggested that he may have committed research “fraud.” The 2011 Conservative Political Action Conference had a booth where attendees could throw eggs at his picture. There was a flood of hate mail, much of it containing death threats: “Your work is finished. YOU ARE GOING TO HANG SOON!”
“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 (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 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.
Within days, the heist—soon dubbed “Climategate“—was all over the news. Glenn Beck called it a “potentially major scandal”; Fox News crowed that the emails “undercut the whole scientific claim for man’s impact on global warming.” Rep. James Sensenbrenner (R-Wis.) decried (PDF) them as evidence of “scientific fascism.”
The immediate impact on public opinion was dramatic. A poll by Yale and George Mason University (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 (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. 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 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. He says his mining ties don’t affect his views on climate change and insists that his prolific blogging 