On the morning of November 17, 2009, I awoke to learn that my private e-mail correspondence with fellow scientists had been hacked from a climate research center at the University of East Anglia in the United Kingdom and selectively posted on the Internet for all to see. Words and phrases had been cherry-picked from the thousands of e-mail messages, removed from their original context, and strung together in ways designed to malign me, my colleagues, and climate research itself. Sound bites intended to imply impropriety on our part were quickly disseminated over the Internet. Through a coordinated public relations campaign,...

It is November 27, 1995, several years before my colleagues and I published our “hockey stick” study. Bill Clinton has been president for nearly three years. The Dow Jones Industrial Average just passed the 5,000 mark for the first time. The TV series E.R., created by novelist Michael Crichton, is the top-rated show on television.

In Madrid, Spain, the Intergovernmental Panel on Climate Change (IPCC) is holding the final plenary meeting for the Second Assessment Report, the purpose of which is to summarize the consensus among scientists regarding the extent of humanity’s impact on Earth’s climate. At a nearly identical...

When I entered the field of climate research in the early 1990s, the science was just coming of age. Major research centers around the world were using some of the fastest supercomputers available to run ever-more sophisticated models of Earth’s climate. Important new observations were coming in. Thermometer measurements showed that the globe—both land and ocean—had by that time warmed approximately 1 degree Fahrenheit over the past century. The accumulated loss of ice during the previous four decades from melting glaciers around the world could fill Lake Huron. An increasing number of climate measurements were painting a picture...

When I first began to work with my Ph.D. adviser Barry Saltzman in the early 1990s, he, like many other climate researchers at the time, remained unconvinced that there was yet a detectable human influence on the climate. You might say that Barry was skeptical. Scientists should in fact strive to be skeptics—in the truest sense of the word. That is to say, they should always apply healthy scrutiny to any new claim or finding. True skepticism, however, demands that one subject all sides of a scientific contention or dispute to equal scrutiny and weigh the totality of evidence...

Although scientific revolutions in how we see the world do occur, the bulk of our scientific understanding comes from the cumulative impact of numerous incremental studies that together paint an increasingly coherent picture of how nature works. The hockey stick was no different. To employ a mixed sports metaphor, the hockey stick did not suddenly appear out of left field. Rather, it arose as a logical consequence of decades of work by paleoclimate researchers that led to increasingly rich networks of climate proxy data and the introduction of new ways to use such data to reconstruct past climates.My colleagues and...

In the 1990s, as the scientific evidence for human-caused global warming grew stronger and calls for action to curtail greenhouse gas emissions grew louder, fossil fuel industry executives made a critical decision. Rather than concede the potential threat climate change posed and the necessity of ultimately reducing fossil fuel use, they would instead engage in a massive, media-savvy public relations campaign. The strategy was simple: While presenting a seemingly forward-thinking, proenvironmental public face, oil companies and allied economic and political interests would, behind the scenes, use various means to sow doubt about the validity of the underlying science on climate...

Skepticism plays an essential role in the progress of science. Properly employed, it is a key self-correcting mechanism that helps lead science inexorably, if erratically, toward a better understanding of the natural world.¹ Yet, as the philosopher Bertrand Russell’s statement above reveals, skepticism in science can also be abused. His admonition has proven remarkably prophetic in the context of the climate change denial movement, wherein the term skeptic has often been co-opted to describe those who simply deny, rather than appraise critically.

Skepticism in the sense of critical consideration of evidence is intrinsic to the scientific enterprise. It is inherent...

The most critical development in the tale of the hockey stick—the prominent display of the MBH99 graph in the IPCC Third Assessment Report’s Summary for Policy Makers in 2001—was beyond my control. In hindsight, it would have been wiser for the authors of the summary to instead have shown the other figure from our chapter which compared three different reconstructions that collectively pointed to the same conclusion: that recent warmth was anomalous in a millennial context. The fact that the MBH99 hockey stick alone had been featured in the policy makers’ document would establish it as a fundamental...

As we entered the new millennium, the hockey stick emerged as a central object of attack in the broader battles waged against climate science, and the attacks became increasingly political. Among them was an effort by the Bush administration to purge the hockey stick from a government science report, a hostile hearing held by a prominent congressional climate change denier to attack our work, and a denunciation of our work by that same congressman on the floor of the U.S. Senate on the eve of a vote on a key climate bill.

Five years after the IPCC Third Assessment Report...

I instead got a dubious honor of a different sort some five years earlier: On February 14, 2005, I received a Valentine’s Day present—a rather unwelcome one—from the Wall Street Journal ( WSJ ).³ My likeness was featured as one of the paper’s stylized, hand-rendered portraits on the front page accompanying the article “In Climate Debate, the ‘Hockey Stick’ Leads to a Face-Off” by environment reporter Antonio Regalado. The article reported the latest attacks on the hockey stick by Stephen McIntyre, whose likeness was also featured on the front page. McIntyre missed making the cover of the Rolling...

In The Demon-Haunted World, Carl Sagan recounts an episode from the McCarthy era involving the distinguished American physicist Edward U. Condon.¹ Condon had been a participant in the Manhattan Project to develop an atomic bomb; the director of the National Bureau of Standards; and president of the American Physical Society. In 1948, he came under attack by the House Committee on Un-American Activities, chaired by Representative J. Parnell Thomas (R-NJ). During the course of the hearings, Thomas variously referred to Condon as “Dr. Condom,” the “weakest link” (i.e., for American security],² and even the “missing link.” Most remarkable, though, was...

The appearance of two dueling reports within weeks of each other in early summer 2006 constituted the next major development in the Hockey Stick battle. The first of the reports, Surface Temperature Reconstructions for the Last 2,000 Years, commissioned by Representative Sherwood Boehlert (R-NY), was published on June 22 and carried the imprimatur of the National Academy of Sciences (NAS).¹ The NAS committee was chaired by a leading expert in statistical climatology, Gerald North of Texas A&M University, and consisted of a blue ribbon panel of a dozen experts with diverse relevant expertise, including leading climate scientists, paleoclimatologists, and statisticians,...

In 2007, climate science was on somewhat of a winning streak. Al Gore’s summer 2006 documentary An Inconvenient Truth, love it or hate it, had introduced a far greater number of Americans to the science of climate change than ever before. Many media outlets were now treating the scienfific evidence more seriously, not inserting a contrarian in every piece for “balance.” Even Frank Luntz of the infamous “Luntz memo,” which had coached climate change deniers on their messaging back in 2002, had now come to accept the reality of humancaused climate change.¹ This same summer, the Intergovernmental Panel on Climate...

By early 2009, a troubling complacency had emerged among climate scientists. Perhaps it was the result of a confluence of seemingly gamechanging events over the preceding few years: the rather conclusive and well-publicized Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment, the increased public awareness resulting from the highly successful movie An Inconvenient Truth featuring Al Gore, the generally improved media coverage, and the images of devastation thrown up by several natural events—such as the 2005 hurricane season and hurricane Katrina in particular—that served as wake-up calls to the public of potential looming threats from climate change. On...

The most malicious of the assaults on climate science would be timed for maximum impact: the run-up to the Copenhagen climate change summit of December 2009, a historic, much anticipated opportunity for a meaningful global climate change agreement. ¹ The episode began with a crime committed by highly skilled computer hackers, followed by a massive public relations campaign conducted by major players in the climate change denial movement.

On November 17, 2009, RealClimate was hacked by someone operating via an anonymous server located in Turkey. At roughly 6:20 a.m. EST, the hacker had uploaded a large file, FOIA.zip, to the...

Though hardly surprising to those who had taken a hard, honest look at the matter, each of the investigations launched in response to the climategate affair ultimately proved exculpatory. That applied not just to me, but to the scientists of the University of East Anglia’s Climate Research Unit (CRU), and indeed all of the scientists who were embroiled in the manufactured scandal, as well as to the underlying science of climate change itself.

At the end of March 2010, the House of Commons Science and Technology select committee of the UK Parliament issued its findings.The report noted that CRU’s “analyses...

We look back now with revulsion at the corporate CEOs, representatives, lobbyists, and scientists-for-hire who knowingly ensured the suffering and mortality of millions by hiding their knowledge of tobacco smoking’s ill effects for the sake of short-term corporate profits. Will we hold those who have funded or otherwise participated in the fraudulent denial of climate change similarly accountable—those individuals and groups who both made and took corporate payoffs for knowingly lying about the threat climate change posed to humanity, those who willfully have led the public and policy makers astray, and those politicians and media figures who have sought...