Climategate Revisited: New Theory Explains The Tree Ring Controversy

The tree-ring divergence problem, at the center of 2009’s “Climategate,” can be explained by normal changes in light intensity Mark Ralston/AFP/Getty
 




by Elijah Wolfson, Newsweek, May 7, 2014

In November 2009, climate skeptics had their day in the sun when an anonymous hacker posted years' worth of emails sent back and forth between some of the world’s most prominent climate scientists, working with the Climate Research Unit (CRU). Buried within these thousands of emails were a handful of fragments that skeptic seized on as proof positive that climate scientists had fabricated the idea of man-made global warming. After the emails were made public, a media frenzy ensued; “Climategate” culminated in deep investigations into the legitimacy of the science that backed of the theory of a man-made global warming. Ultimately, the CRU scientists were acquitted of any malfeasance, and their science was verified to be clean, but the events had a significant impact on public perception.

Five years later, a new study published in Nature Communications may help cool the lingering fallout from Climategate. The study, led by Alexander Stine of San Francisco State University and Peter Huybers at Harvard University provides a compelling scientific explanation for the issue at the center of the 2009 controversy: the tree-ring divergence problem.

Scientists are nearly 100% sure of the world’s daily temperatures for the last 150 years or so—which is when we started to keep daily weather records. But before that, it’s a little less clear. So many climate scientists, on both sides of the debate, have come to use tree rings, in conjunction with other proxy measurement tools like coral growth, isotope variation in ice cores, ocean and lake sediment records, and more, in order to reconstruct temperatures changes over years.

“The tree-ring records are in many ways the best record we have,” says Stine. “There are trees all over the Earth, and they have this annual resolution, which very few of our proxies do.” Trees reflect a more human time scale; ice core records show temperature changes across time periods on the order of millions and millions of years, while trees rings track changes year by year. In temperate climates (like much of the U.S.), trees only grow during the part of the year referred to simply as the growing season. In the Northern Hemisphere, this is the spring and summer. In a good growing season—where there’s plenty of precipitation and warm temperatures for months on end—the resulting growth ring will be relatively wide. In poor growing seasons, the rings will be narrow.

It’s not perfect, but it’s a pretty decent proxy for those years before thermometers and recordkeeping.

The problem, though, is that since the 1960s, Arctic tree-ring growth seems to not match the actual temperature records we have. Thermometer measurements show a sharp jump in temperature in the late 20th century. This is one of the primary arguments for man-made climate change: as the global population increased, and we began to build bigger and more industrial cities, and rely more on fossil-fuel based travel in cars and planes, humans greatly sped up the warming of the planet. But Arctic tree-ring records don’t back this up. In fact, they seem to indicate a decline in temperatures during those years. This is called the tree-ring divergence problem, and has been recognized, accounted for, and written on extensively—not the least notably by Keith Briffa, one of the CRU scientists singled out as supposedly burying data after the emails were leaked, in a paper published almost a decade before Climategate.

Briffa had put forth—and the scientific community had long-since accepted—the notion that this “divergence issue” was actually a strong decline in tree sensitivity to temperatures after 1960—and not the temperature themselves. In fact, Stine says, if you look more closely at the numbers you can see that year to year, the rings on an individual tree in the Arctic Circle still do change size with year to year temperature changes—there is just a “systematic underprediction by the tree rings” that began in the mid-20th century. “And when you average all the trees, everything goes away except for that systematic underprediction.”

In 2009, critics from latched on to one email in which Phil Jones, at the time the head of the CRU, wrote that in a recent graph (prepared for a World Meteorological Organization Report) he used “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.”

It was unfortunate phrasing. Jones was referring to the famous “hockey stick” graph used by Michael Mann, the director the Earth System Science Center at Pennsylvania State University, in an article published in the journal Nature, in which he combined a number of different data sources to show overall global temperature increase over the years. According to Mann, the criticism was simply a “cynical misrepresentation” of Jones’s email, which he tells Newsweek “spoke of something that was already well known to the scientific community—that tree-ring density data should not be used to depict temperatures after 1960.” Following the release of these emails, Mann was extensively investigated for any scientific misconduct—and completely acquitted.

Today, Mann says that the whole Climategate fiasco was based around the misconception that the only evidence there is for climate change from the paleoclimate record (i.e., the record of the climate change throughout the entire history of earth) was from tree rings. “Nothing could be further from the truth,” he says. “[There are] multiple independent lines of evidence for human-caused climate change. And the most important evidence for modern warming comes from instrumental measurements—thermometers—not paleoclimate data.”

Stine points out that in most of the scientific papers at the time, researchers would typically plot tree-ring records and thermometer records next to each other—then make an argument about the gaps between the two. “I don’t think you need to argue too hard to convince me that thermometers are better than tree-ring records,” says Stine. “What got turned into a big hoopla was the putting together of a summary graph, to say ‘this is our best interpretation of what the numbers have been.’ ”

Nevertheless, Stine and Huybers set out to explain the tree-ring divergence data—mostly, Stine says, because he wanted to get a better sense of what the Earth’s most ancient trees are actually able to tell us. Their solution is simple, elegant, and intuitive: global dimming. Since the 1960s—exactly when tree-ring data started to go awry—“there’s been large scale decreases in the amount of light that’s reaching the earth,” says Stine. It’s fairly easy to see why, too. In rapidly industrializing parts of the world with fewer emissions laws—like Southeast Asia—the light decline is particularly steep, and continues into the 21st century. On the other hand, in areas like the U.S. and Europe, you see a rapid decline in the middle of the 20th century, but then light levels steady themselves later on—right around the time most air pollution laws were put into place.

Trees of course, need light to grow—they use photosynthesis to turn light energy into chemical energy to fuel all their activities, including their growth. “My hypothesis,” says Stine, “is that the light is directly affecting tree growth: You turn down the lights, you turn down tree growth.

In the scientific community, skeptics of human-induced climate change have mostly been silenced; the 2014 National Climate Assessment published Tuesday unequivocally laid global warming and its resulting environmental impacts at the feet of human civilization, stating ominously that “climate change, once considered an issue for a distant future, has moved firmly into the present.”

 

http://www.newsweek.com/climategate-revisited-new-theory-explains-tree-ring-controversy-250208

Newsweek: A Change in the Legal Climate

by Kurt Eichenwald, Newsweek, January 30, 2014

For years, the tiresome back-and-forth has played on like a broken record. Scientists announce new data showing that the global climate is warming, creating potentially devastating changes in the world. Skeptics attack, proclaiming the researchers are lying as part of a conspiracy to gin up research funding. The climatologists respond, calling the detractors anti-science deniers who push their claims at the behest of fossil-fuel companies that stand to lose the most if the research is accepted as fact. And round and round it goes, with no end in sight.

That is, until maybe now, with the spinning potentially coming to a stop in the most unlikely of places - a Federal district court in Washington, D.C. There, a little-noticed lawsuit filed by one of the world's preeminent climatologists against a premiere conservative publication and a conservative think tank is moving forward, and both sides - absent dismissal or settlement - will have to put up or shut up.

The suit filed by Michael Mann, director of the Earth System Science Center at Pennsylvania State University, claims that the National Review and the Competitive Enterprise Institute (CEI) libeled him in a pair of articles in which they stated he had manipulated climate data and that the fraud had been covered up by his employer, which said its investigation concluded he had done nothing wrong. To make the point, the CEI writer, Rand Simberg, drew a comparison between Penn State's handling of abuse allegations against Jerry Sandusky - the university's longtime assistant football coach convicted as a child molester - and its review of Mann's work.

"Mann could be said to be the Jerry Sandusky of climate science, except that instead of molesting children, he has molested and tortured data," Simberg wrote in the article Mann says is libelous.

Mark Steyn, a writer with National Review Online, wrote about the Simberg article and tossed in his own thoughts. While at first openly shying away from the Sandusky metaphor, Steyn called some of Mann's most prominent work "fraudulent" - a graph of historical temperatures showing rapid rises in modern times, which is widely known as the "hockey stick." Then Steyn returned to the references to the child molester.

"Graham Spanier, the Penn State president forced to resign over Sandusky, was the same [person] who investigated Mann," Steyn wrote. "And, as with Sandusky...the college declined to find one of its star names guilty of any wrongdoing." He went on to say that the investigation "was a joke."

Ugly stuff. Accusations of scientific fraud, lies, cover-ups and then comparisons with some of the most horrific crimes imaginable. Because of the prominence of his research in climate change science, similar - though rarely so caustic - attacks had been leveled at Mann for years by skeptics. But circumstances had changed. Not only had the two writers gone further than most by creating an equivalence between Mann and an infamous child molester, but they appear to have done so at the worst possible time.

For months before those articles, Mann and other climatologists had been speaking among themselves about the need to start fighting back against the attacks on their work and their character. The science is on their side, they argue, and by not responding aggressively against the skeptics, they have allowed the discussion to become derailed. And if critics have slandered or libeled them, they shouldn't stand for it.

"If we don't step up to the plate, we leave a vacuum [for] those with an ax to grind," Mann says, while cautioning that he would not specifically address the lawsuit. Mann has no doubt some critics are advancing their positions honestly, but he believes that responding to bad-faith attacks on climatologists and their work is "a call to arms to our fellow scientists. We should not apologize for trying to inform that discussion."

Before filing his suit, Mann told both CEI and National Review that he would take action if they didn't remove the offending statements and apologize. While CEI edited some of the more aggressive words out of Simberg's online piece, National Review practically sneered. In a piece headlined "Get Lost," the magazine's editor, Rich Lowry, dismissed Mann's warning, labeled any litigation as nothing more than a nuisance and all but invited the climatologist to sue by declaring the magazine would use the discovery process to investigate and write about him. Lowry also asked readers to contribute money to help finance any legal battle.

The email held up as the most damning was from 1999, which, in regard to Mann, made reference to "Mike's Nature trick," and used the words "hide the decline" in reference to something one of the scientists was preparing that compared different means of reconstructing historical temperatures through proxies like tree rings. This, the skeptics claimed, showed that Mann had devised a dishonest way to disguise historicallyfalling temperatures. They demanded investigations of Mann and the other climatologists on the emails to prove their research was part of a fraudulent scheme to fool the world into believing in climate change.

While those accusations were blared across television and newspapers, the scientists countered that the skeptics were cherry-picking words, misrepresenting them and ignoring the scientific meaning of what was being said. At the most basic level, the scientists said, a 10-year-old email, regarding a single piece of information being prepared for one group - the World Meteorological Organization - was hardly proof of a conspiracy.

"The email was written at the end of the warmest month of the warmest year on record," Mann says. "It got contorted illogically, in a way that makes no sense at all until you understand the context."

While "trick" and "hide the decline" were often cited by skeptics as being related, they were in fact referring to two different things, Mann said. The "Nature trick" referred to a means of comparing two data sets on a single graph, which Mann and other scientists had used in 1998 for an article in Nature magazine, he says. In reconstructing temperatures, one of the proxy models for charting them did not extend past the early 1980s, Mann explains, so the reviewers of the article asked for the climatologists to add instrumental temperatures for the two decades that followed - in other words, two different means were used to plot historic temperatures. The separate curves were labeled, and the data for both could be downloaded by anyone who wanted to review them.

The words "hide the decline" had nothing to do with temperature, Mann says. The use of tree ring data as a proxy for temperature reconstruction was known to be useful only up to the 1960s, when the density of tree rings dropped in response to warming temperatures. In other words, the email wasn't discussing declines in temperatures, but declines in tree ring growth. The divergence between tree ring data and temperature could not be explained, although some scientists theorized it had something to do with pollution. But it was no secret - it has been publicly discussed in peer-reviewed science journals since 1995. Either way, the decline in tree ring density compromised the quality of it as a proxy for temperature; the "hiding" phrase, while inartful, was referring to not displaying tree ring data over years when it was known to be misleading, Mann says.

Climate scientist Michael Mann applauds as he listens to former President Bill Clinton during a rally for Democratic gubanatorial candidate Terry McAuliffe, in Charlottesville, Va., Wednesday, Oct. 30, 2013. AP Photo/Steve Helbe

The skeptics have dismissed these explanations as hokum, and argue that the email speaks for itself, proving climate science showing warming is based on manipulated data. But multiple investigations - at Penn State, the University of East Anglia, the United Kingdom's House of Commons Science and Technology Committee, the U.K. Secretary of State for Energy and Climate Change, the Environmental Protection Agency (EPA), the National Academy of Science - have independently concluded that there was no basis for claims that the emails show Mann and the other climatologists had engaged in misconduct or fudged the data. The decline was about tree rings; the trick was about a publicly revealed technique used in Nature. Moreover, in 2010, CEI filed a request to the EPA calling for reconsideration on some of its findings, citing in part the emails. The EPA responded by brushing aside the allegations: the emails among the climatologists "do not show either that the science is flawed or the scientific process has been compromised." The agency added that it had investigated the emails "and found no indication of improper data manipulation or misrepresentation of the results."

Which leads back to the court case between Mann, CEI and National Review. In the articles, Mann says in his lawsuit, the think tank and the publication ignored more than half a dozen investigations that found no scientific wrongdoing, focusing almost exclusively on the Penn State inquiry in order to call him a fraud. CEI also mentioned the National Academy of Science's investigation, but dismissed those findings by saying the body had obtained information from Penn State, meaning the inquiry was "not truly independent." The basis mentioned by CEI to call the Penn State investigation a whitewash was stating it had only interviewed Mann, and "seemingly ignored the content of the emails."

After Mann filed his lawsuit, the defendants attempted to have it thrown out, stating that the accusations were merely opinion and hyperbole protected under the First Amendment, and that the climatologist failed to allege anyone acted with actual malice. What followed was a procedural train wreck, resulting in an order rejecting the motion to dismiss, an appeal of the order, a reversal and, this month, a new order from a new judge refusing to toss out Mann's suit. That new order has been appealed by CEI and Simberg; if the court refuses to reverse, the next step would be discovery and then the filing by the defendants of a summary judgment motion with the lower court seeking dismissal before trial.

While some of the defendants or their representatives declined interviews or did not respond to emails, those who did speak expressed confidence that they would prevail. The statements in the CEI article "are fully protected speech under the First Amendment and will likely be treated as such by the Court of Appeals," said Andrew Grossman of BakerHostetler, who represents the think tank and Simberg. Anthony Dick, a lawyer with Jones Day, which represents National Review, declined to comment. Steyn, the author of the original National Review piece, said by email, "I stand by everything I wrote, and I'm happy to defend it in court and before a jury - if it comes to that."

There have been signs, however, of discord among the defendants. National Review recently switched law firms to Jones Day, while Steyn is now representing himself after a dispute over strategy.

In an email and on his website, Steyn expressed frustration that National Review refuses to take on Mann directly, in court, rather than spending so much money on legal maneuvering to keep the case from going to trial. "You can't win a free speech battle if you're not prepared to fight it, and I don't think I'm giving anything away when I say that the silence of NR's editorial team (the only guy over there who ever writes anything is the publisher) has been very dispiriting," Steyn said by email.

Steyn also said - as did his co-defendants in court filings - that the investigations of Climate-gate didn't back up Mann's conclusions, and he was legitimately questioning the science behind the climatologist's work. "He's suing me for calling his hockey stick 'fraudulent' ", Steyn said by email. "Which it is."

Mann says he is frustrated about the bitterness of the years of disputes between climatologists and the skeptics but now accepts that responding to attacks will be part of the job for all of them.

"A lot of us would much rather be spending our time doing science, but an increasingly large amount of our time is spent on defending ourselves against bad-faith attacks," he says. "Over time, I have come to embrace that."

http://mag.newsweek.com/2014/01/31/change-legal-climate.html

Barry Bickmore: “How to Manipulate Rubes into Covering Your Legal Bills,” Mark Steyn edition

by Barry Bickmore, "Climate Asylum" blog, January 26, 2014

If you haven’t been following the Michael Mann v. National Review, Inc. et al. case, here’s a quick summary.  Rand Simberg, of the Competitive Enterprise Institute, thought he had a clever way to capitalize on the Jerry Sandusky scandal at Penn State.  Compare Penn State climate scientist Michael Mann to Jerry Sandusky, and accuse him of producing fraudulent scientific data!  This charge was repeated by Mark Steyn, blogging for the National Review magazine, and of course, neither Steyn nor Simberg had the presence of mind to clearly label their accusations as opinion, or provide any caveats whatsoever, or… you know… provide any “evidence” for the accusations.  Having put up with such accusations by wingnuts for a number of years, Mann sued.  Of course, the defendants have been complaining about their “free speech” rights, and trying to get the case thrown out based on certain laws meant to stop people from using defamation/libel suits to stifle legitimate public discourse.  But there are limits on “free speech,” and now two different judges have ruled that they would allow the case to proceed, because it is likely to succeed if presented to a jury.  Meanwhile, Mark Steyn and others at the National Review… well, especially Steyn… can’t seem to keep their pie-holes shut long enough to keep from making their prospects even worse.  For instance, Steyn let loose with some searing remarks about how stupid and incompetent the first judge (who recently retired) was, which appears to have resulted in a parting of the ways between Steyn (and probably the NR) and their lawyers, so that now Steyn is representing himself (badly).  Anyway, if you want to  protect your “right” to publicly throw out baseless accusations of fraud, it’s going to cost you some cabbage, and so lately Steyn has been out begging the rubes to finance his Crusade for Freedom and Justice.  Recently, he did so on Hugh Hewitt’s radio show.  Hewitt was quite supportive of Steyn, but given that he claims to be a Constitutional Law professor (and given Steyn’s comments on the show,) I thought it likely that Steyn might not have been completely forthcoming about the nature of the case.  Here’s the note I sent Hewitt through his Facebook page.  We’ll see if he was really misinformed, or just another rube Steyn is trying to manipulate into paying his bills.

Dear Hugh,

I am an active Republican and a geochemistry professor at Brigham Young University.  I noticed that you had Mark Steyn on your show the other day, complaining about how Michael Mann’s lawsuit against him had not been dismissed, and trying to drum up some donations to help him with his legal defense.  I thought you should know, however, that Steyn wasn’t being completely honest with you about the case.

On your show, Steyn seemed to imply that the case was about his right to disagree with Mann’s “Hockey Stick” reconstructions of paleotemperatures over the last 1000 years or so.  This is not the case.  Steyn is being sued because he made the accusation that Mann “molested and tortured data in the service of politicized science,” and that Mann’s scientific work was “fraudulent.”  Both judges in the case have noted that this accusation was a statement of fact rather than mere opinion, and can hypothetically be proved true or false.  It is therefore grounds for a defamation suit, if it can be shown that (1) the accusation is false, and (2) Steyn made the accusation either knowing it was false, or with reckless disregard for the truth.  

I don’t know whether Mann will win the case, or not, but it is clearly not just some frivolous suit meant to stifle legitimate public discourse.  For one thing, the accusation is clearly false.  The main charge against the “Hockey Stick” work was that Mann and his colleagues had misused principal components analysis (a statistical technique) to obtain a certain outcome.  But when scientific bodies such as the National Research Council reviewed the case, they found that the statistics could have been done better, but the mistakes didn’t change the results much.  They also found no evidence of “fraud.”  Now, if you were going to commit scientific “fraud,” wouldn’t you fudge your data so as to actually obtain substantially different results?  The “fraud” charge is just ridiculous, whether or not you believe the “Hockey Stick” accurately describes the temperature evolution over the last 1,000 years.  For another thing, it seems very likely that Mann’s legal team can show that, at the very least, Steyn made the accusation with “reckless disregard for the truth.”  

Why am I so confident about that?  Because several scientific, academic, and governmental panels had already ruled there was no evidence of fraud, and Steyn knew that.  Second, because Steyn can’t seem to keep his ignorant mouth shut.  On your show, for instance, he claimed that the National Research Council agrees with him.  About what?  Certainly not about the fraud charge, which is what he is actually being sued over.  Also consider this passage from one of Steyn’s recent columns.

“In a post at NATIONAL REVIEW’s website, I mocked Dr. Michael Mann, the celebrated global warm-monger, and his ‘hockey stick,’ the most famous of all the late-Nineties global-warming climate models to which dull, uncooperative 21st-century reality has failed to live up. So he sued.”

Ummm… Aside from the fact that Steyn is once again implying that he is being sued for something other than calling Mann’s work “fraudulent,” I note that Steyn apparently thinks the “Hockey Stick” is a “climate model” that made predictions about the 21st century.  It isn’t.  It didn’t.  So in other words, Steyn is insisting on his right to publicly call a scientist’s work “fraudulent,” when he clearly has made no effort to understand what said scientific work is even about.  So let’s just please ignore all his posturing about his right to his opinion about the matter.  He doesn’t even care what the facts are.

So, Hugh, I believe you said you are a Constitutional Law professor.  Are you still quite so hot to defend Steyn’s foolishness?

Sincerely, 

Barry Bickmore

http://bbickmore.wordpress.com/2014/01/26/how-to-manipulate-rubes-into-covering-your-legal-bills-mark-steyn-edition/

Michael Mann's "The Hockey Stick and the Climate Wars" -- Now in paperback, highly recommended

by Rick Piltz, Climate Science Watch, November 22, 2013

In The Hockey Stick and the Climate Wars, Michael Mann brings a unique vantage point to his "dispatches from the front lines," chronicling the war on climate science and scientists by the global warming denial machine, alongside the advance of scientific research and understanding.  Prof. Mann tells an essential story, as many readers of this site are well-aware -- with detail, references, and interpretation of events during the past two decades that make this book not only a very good read, but a good reference work on science versus the denial machine.

The Hockey Stick and the Climate Wars: Dispatches from the Front Lines, is available from Amazon and from Columbia University Press. If you order from Columbia University Press, use the promotional coupon code HOCMAN to get a 30% discount on the purchase price.

*    *    *

The global warming denial machine's predatory "Serengeti strategy" of singling out individual scientists and scientific findings for attack has been applied relentlessly to several leading climate scientists, none more so than Mann and the iconic "hockey stick" graph from paleoclimate research published in 1998. That pathbreaking work found that warming in the late 20th century was unprecedented over the last millennium. Since then, a growing and diverse body of painstaking paleoclimate research has produced multiple studies that essentially confirm and strengthen that early finding.

Mann begins his chronicle by revisiting 1995, when the IPCC Second Assessment Report concluded that "the balance of evidence suggests a discernible human influence on climate." This conclusion, arrived at by the leading climate scientists who had authored the IPCC report, and adopted by the governments of the world in the assessment's Summary for Policymakers, was seen as a threat by climate change contrarians and by a fossil fuel industry-funded campaign of denialism and obstruction.

That campaign of contrarianism and obstruction had been underway at least since the time of the 1992 Earth Summit held in Rio de Janeiro, where the foundational Framework Convention on Climate Change was adopted.  I saw it in operation at a meeting at the State Department under the first Bush Administration, and in testimony at a hearing on global warming I organized as a professional staff member on the House Science, Space and Technology Committee in 1992.

So, with the IPCC 1995 report, the denialists began to hone their Serengeti strategy in earnest, singling out Ben Santer, lead author of the climate change detection and attribution chapter of the report, for an attack that was intended to destroy his reputation and career. They failed to do this -- Santer remains an active scientist at the cutting edge of research -- but they did establish a method and a template for action by a denial machine that has played a seriously destructive role in recent years.

In addition to a good discussion of the early years of what Mann calls the "climate wars," the first several chapters of the book also discuss the advancement of climate research through the 1990s. Chapters 5 ("The Origins of Denial") and 6 ("A Candle in the Dark") run through a rogues gallery of predatory denialists and contrarian scientists and how they came to use the media and the Internet as a substitute for peer-reviewed science -- along with a good discussion of how real science advances, and the importance of the major, multiply-authored and carefully vetted climate science assessments.

The scientifically based assessment, produced by leading experts in a field, which synthesizes the state of knowledge and relates it to the concerns of its intended users, is an exceptionally significant scientific-intellectual creation of the past several decades.  And whether it's the international assessments of the Intergovernmental Panel on Climate Change or the periodic U.S. National Climate Assessments, the denial machine always goes to great lengths in seeking to discredit them.

I saw this in action while working in the U.S. Global Change Research Program/Climate Change Science Program Office, in particular under the second Bush Administration. The Bush White House did its best to ignore the IPCC Third and Fourth Assessment Reports (2001 and 2007), as well as the Arctic Climate Assessment Report (2004) -- and they went so far as to officially disown and effective suppress the first National Climate Assessment report (2000-2001). I have written and spoken about this Bush Administration science scandal at length on numerous occasions.

The work of Mann and his co-authors on the temperature record from paleoclimate research, i.e., the hockey stick graph, was given high salience in the IPCC 2001 Third Assessment Report -- and thus, predictably in retrospect, the authors and their findings became the target of a Serengeti strategy denialist attack that continued over the past decade. We had seen it with Ben Santer, with Jim Hansen, the most eminent federal climate scientist, and with my dear friend the great Stephen Schneider, a pioneering scientist on multiple fronts who also knew how to communicate. The denialists acted as though they believed that, if one or a few key scientists, or a single piece of significant research, was discredited, that the science of anthropogenic global warming would collapse.

But the denial machine hasn't really been interested in advancing the science of climate change, which is a complex and multifaceted body of work developed by thousands of scientists. Their fundamental aim is more in the realm of politics: manufacture an enhanced impression of fundamental scientific uncertainty -- create a sense in the media, in public opinion, that there is a raging debate in the science community over what are essentially widely-agreed findings -- provide talking points to elected politicians who have an interest in blocking policy action on climate -- and use attack tactics to question the credibility of climate science as an enterprise and undermine the reputations of leading scientists.

In Chapter 7-11 Mann tells his story, as a participant, of a years-long series of climate war battles, leading up to late 2009, over the effort to undermine climate science, in particular by undermining the temperature record established by Mann and his fellow paleoclimate researchers. Some of this focuses on the denial machine inside the Bush Administration (events that led to my decision to become a whistleblower are summarized on pages 110-112). Some of it focuses on the denial machine in Congress. These chapters document Mann's perspective on and analysis of the criticism from McIntyre and McKitrick, the inquisition of the scientists by the egregious Rep. Joe Barton (R-Texas) and the notorious Wegman report he commissioned, and the sorry case of the Soon and Baliunas study and how it was used by the denialists.

This, like the rest of the book, is valuable memoir material on the collision between the world of science and the realities of politics. For those who already know something about these events, Mann's narrative is a must-read. For attentive readers coming to this story for the first time, it is likely to be a real eye-opener.

Then, in Chapter 14, 207 pages into the book, we come to 'Climategate' -- the bogus controversy over scientists’ stolen emails – a denialist propaganda coup and allegation of scandal that was mishandled with shameful credulity in the mainstream media. Climate Science Watch had quite a bit to say about this matter while it was unfolding, and in connection with events leading up to it, in particular the denialist-contrarian attack on EPA's "Endangerment Finding" on greenhouse gases in 2009 -- including posting relevant statements by Santer, Schneider, and Phil Jones. We defended the scientists throughout against what was clearly a scurrilous attack in the war on climate science and scientists. Mann's 26-page exposition on "Climategate: The Real Story" is a must-read discussion by one who was caught up in the storm and profoundly influenced by the experience.

In the final chapter of the book, "Fighting Back," in an Epilogue, and now in a 14-page Postscript to the paperback edition, Mann brings the story up to date. As Climategate receded in the rearview mirror, ongoing attacks on climate science continued. But at least some members of the science community, which had been so ill-prepared to deal with the kind of politically motivated attacks it was subjected to by the denial machine, seemed to learn from bitter experience the need to confront the attacks and push back in a more timely and concerted way. Scientists have an essential role to play in keeping the public discourse honest, and we need more of them who have the ability and the guts to help hold politicians and the media accountable for not letting scientific illiteracy, misinformation, and the denial machine drive the public narrative.

During the past 25 years, the climate science community, through an extraordinary collaborative effort, has made great advances in understanding the Earth system, global climatic disruption, and the role of human activity in influencing global change. Some of them have made great contributions in communicating their findings and the implications of climate change -- in scientific assessments, congressional testimony, books, articles, and media appearances. There is much more to be done on this score.

We need more scientist-citizens -- experts who sometimes will step out of their labs, as it were, to act as public intellectuals, addressing their fellow citizens and those with policymaking and management responsibilities, drawing on their expertise and translating it for 'civilians' in a way that will elevate the national discourse on climate change and push society to do what needs to be done.

But climate scientists have identified and are characterizing a set of problems that go far beyond the ability of the science community to solve, no matter how well scientists communicate. Climate change must be dealt with in the arenas of politics, public policy, management, the media, and public opinion -- where scientific literacy is generally low and many conflicting agendas compete, driven by leaders with values, and interests to protect, that may be indifferent to, or even antithetical to, the norms and findings of scientific research. Communication and advice from the science community isn't simply delivered into a rational, intellectually sophisticated, public-spirited, pragmatic, problem-solving arena (although reading a nearly impenetrable Summary for Policymakers of an IPCC assessment report might give the impression the scientists believe it does) -- rather, it gets caught up in a political atmosphere that can be downright toxic.

Congress has settled into a gridlock of climate policy inaction, and international negotiations under the climate treaty drag along ineffectually. The U.S., and the world, are far short of where they need to be in order to deal meaningfully with the threat of global climatic disruption. That is a problem that concerns all of us.  But it is great, and indispensable, to have outspoken scientist-citizens who are willing to join the fray.

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A review at Skeptical Science includes this:

The sustained level of attack that Mann has been forced to endure is extraordinary. He's withstood threats to himself and his family, sustained PR campaigns targeting his university, mocking Youtube videos, slandering Google ads and intimidation from Republican congressmen and district attorneys. While reading through the litany of attacks, I couldn't help wondering what the attackers thought will happen - if they successfully intimidate the scientists, do they think the ice sheets will stop sliding into the ocean and sea levels will stop rising?

The book ends on a hopeful note. The virulent attacks on climate scientists have woken a sleeping bear as the scientific community has not stood by while their own are attacked. Mann speculates that perhaps Climategate and the attack campaign was the turning point when the denial movement tacitly accepted they had no honest, science-based case for denying human-caused global warming and had to resort to smearing and intimidation.

(UPDATE November 28) Also see these reviews:

Sylvia S. Tognetti, More reasons to read The Hockey Stick and the Climate Wars, November 28

D.R. Tucker, Amazing Grace: A Survivor's Story, November 26

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For the record, some earlier posts, selected from a large archive of Climate Science Watch posts that cover events and themes developed in The Hockey Stick and the Climate Wars:

“The Hockey Stick and the Climate Wars” – and a skirmish with denialists on Amazon (February 11, 2012)

On the denialist inquisition against Mann and the University of Virginia:

Closing the book on Ken Cuccinelli, climate science denialist witch-hunter and Tea Party favorite (November 6, 2013)

Virginia Supreme Court tosses out AG Cuccinelli inquisition on Michael Mann (March 2, 2012)

Court rules for Univ. of Virginia and Michael Mann against denialist inquisition - scholarly e-mail and documents are protected communication (September 17, 2012)

Washington Post editorial: Resist denialist ‘freedom of information’ harassment of climate change scientists (May 30, 2011)

On Mann's current defamation lawsuit against the National  Review and the Competitive Enterprise Institute:

DC judge denies another effort to derail Michael Mann's defamation lawsuit (September 13, 2013)

On the "Climategate" stolen scientists' email controversy:

Interview with Michael Mann on the Penn State Final Report and the war on climate scientists (July 1, 2010)

A review of the climate science stolen email controversy, with a few lessons for the future (April 28, 2011)

NSF IG report on Michael Mann investigation: “No research misconduct. Case closed.” Don't bother telling Rick Perry.

Ben Santer: Open letter to the climate science community

Stephen Schneider: Climate Denier Gate a case of Science as a Contact Sport

Open letter to Congress from U.S. scientists on Climate Change and Recently Stolen Emails

Debunking ‘Climategate’

On finding one's email in the hacked climate science email files

On the Congressional denialist witch hunt:

UK Guardian: “US Senate’s top climate sceptic accused of waging ‘McCarthyite witch-hunt’”

Sen. Inhofe inquisition seeking ways to criminalize and prosecute 17 leading climate scientists

Sensenbrenner IPCC witch-hunt: Attempt to blacklist climate scientists must be rejected

Rep. Sensenbrenner projects “fascism” and “fraud” onto scientists, is rebutted at hearing

Deep Climate investigation of denialist and “skeptic” attack on Hockey Stick temperature record

Reports and articles on the denial machine:

New Greenpeace report documents machinations of corporate-funded climate denial machine (September 12, 2013)

Popular Science reviews denialists' war on climate scientists

Michael Mann in Washington Post op-ed: “Get the anti-science bent out of politics”

Leading US climate scientists are being subjected to a barrage of right-wing lunatic hate mail

Books on the denial machine:

“Fool Me Twice: Fighting the Assault on Science in America”

"The Inquisition of Climate Science" takes down the denialists

‘Merchants of Doubt’ responsible for climate confusion - book review

Political interference with climate science communication under the Bush Administration:

“The Denial Machine” – Index on Censorship reviews the Bush record on climate science

“Hot Politics”—PBS FRONTLINE program and extended interviews online(April 26, 2007)

Rick Piltz testimony before the Senate Commerce Committee (February 7, 2007)

Climate Science Watch testimony at House Oversight Hearing (January 30, 2007)

Investigation documents political interference with climate science communication (January 30, 2007)

Atmosphere of Pressure (February 2007): Along with the Union of Concerned Scientists, this Government Accountability Project report uncovers new evidence of widespread political interference in federal climate science.

Redacting the Science of Climate Change (March 2007): Details the findings of a yearlong investigation by the Government Accountability Project into political interference at federal climate science agencies.

http://www.climatesciencewatch.org/2013/11/22/hockey-stick-climate-wars-paperback-review/