Tag Archives: hockey stick

The science and politics of climate change

Michael Mann: The Hockey Stick and the Climate Wars – TAM 2013.

Have a look at this video for an excellent description of the history and science of climate change. It’s presented by one of the central figures.

Michael Mann has become a great popular science communicator – especially on climate science and the political attacks on science.

He was effectively forced into this public role by the political attacks on him He tells his story very well in his book  The Hockey Stick and the Climate Wars: Dispatches from the Front Lines. It’s a great read – highly recommended.

Read “Good faith” science – and its enemies for my review of Michael Mann’s book.

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New “Hockey Stick” but same tired old denial

Ian Wishart is on his climate change conspiracy high horse again (see New global warming scandal hits climate science). His fevered imagination has managed to produce a “scandal” out of the publication of a scientific paper. Of course the scandal is based entirely on his climate change denial echo chamber. His denier mates have ripped into this paper. They are obviously very upset by it – more so than normal. It’s worth asking why?

I think the simplest answer lies with the word “Hockey Stick!” This phrase, together with reference to Dr Michael Mann, usually gets them foaming at the mouth. And it’s amazing what rubbish they can spout once so provoked.

This time they are reacting to a new “Hockey Stick” presented in a recent Science paper by Shaun A. Marcott, Jeremy D. Shakun, Peter U. Clark and Alan C. Mix. (see “A Reconstruction of Regional and Global Temperature for the Past 11,300 Years.”) The earlier research had extended back roughly 1,500 years, and suggested that the rapid temperature spike of the past century, believed to be a consequence of human activity, exceeded any warming episode during those years. This new work confirms that result while suggesting the modern warming is unique over a longer period.

The new work compiled the most meticulous reconstruction yet of global temperatures over the past 11,300 years, almost the entire Holocene. They used indicators like the distribution of microscopic, temperature-sensitive ocean creatures to determine past climate. The plots below compare these new results with those found by previous workers


The temperature reconstruction of Marcott 2013 (past 11,000 years) and a collection of reconstructions (past 1800 years) as presented by Mann 2008. (Credit: The two epochs of Marcott and the Wheelchair).

Wishart says the new paper “claimed to have validated the discredited “hockey stick” graph and proven that modern temperatures were the highest in four millennia.” He then goes on to use the authors’ simple acknowledgement that “The 20th century portion of our paleotemperature stack is not statistically robust” to claim their “story is rapidly unravelling” and that this is a “new global warming scandal.”

Bloody hell – is that all it takes to produce a scandal? For a scientist to point out limitations in part of their data (an area already extensively covered by other work)? What does Ian think – that every piece of scientific work must repeat in depth all the previous work? That no existing information can be used?

No of course not. He is just being dishonest. Using anything he can get hold of to weave a story discrediting honest science – and honest scientists. We have seen it all before in the lies he and his climate change denial mates promoted about Dr Michael Mann’s work – the work producing the original “Hockey Stick.”

For example, Wishart’s reference to “the discredited “hockey stick” graph” is a lie he promotes in his book “Con Air” (see  Alarmist con for my review) and is repeated ad nauseum in the climate denial echo chamber. But it is just not true. Far from being discredited this work has been validated again and again. It’s the critics of this work who have been discredited. Been caught lying.

I summarised this several years ago in my article Climate change deniers’ tawdry manipulation of “hockey sticks”. Have a look at that if you want details.

The climate change denial movement worked extremely hard to discredit the work of Michael Mann which produced the original “Hockey Stick.” Mann has described this campaign in his book The Hockey Stick and the Climate Wars: Dispatches from the Front Lines (see The truth about the hockey stick for my review of the book). Their campaign failed. This work has been discredited in one place only – the  biased mind of the committed climate change denier like Ian Wishart.

Meanwhile, if you wish to learn more about the Marcott (2013) paper and their work here are some links:

A Reconstruction of Regional and Global Temperature for the Past 11,300 Years.
Global Temperatures Highest in 4,000 Years
Response by Marcott et al.
Recent Warming Is Still Unprecedented In Speed, Scale And Cause: A Marcott Et Al. FAQ
Fresh Thoughts from Authors of a Paper on 11,300 Years of Global Temperature Changes

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A concise summary of climate change – science and politics

Here’s a relatively short (26 min) video of a lecture by Michael Mann. I think it gives a very concise and accurate picture of the current science of climate change and the political attacks on climate scientists (Mann calls this the scientization of politics).

via The Hockey Stick and the Climate Wars – Michael Mann Speaks at SOS 2012 on Vimeo.

From the video description:

Michael E. Mann- Director of the Earth System Science Center gives a very eye-opening presentation at the 2012 Sustainable Operations Summit. Mann’s presentation highlighted themes from his most recent book: The Hockey Stick and the Climate Wars: Dispatches from the Front Lines. In his talk, Mann discussed the “Hockey Stick,” a graph he created with his colleagues to depict changes in Earth’s temperature dating back to 1000 AD. The graph was featured in the Summary for Policy Makers portion of the 2001 report of the Intergovernmental Panel on Climate Change (IPCC) and became an icon in the debate over human-caused climate change. Mann told the story behind the Hockey Stick, using it as a vehicle for exploring broader issues regarding the role of skepticism in science and the relationship between science and politics.

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“Good faith” science – and its enemies

Book review: The Hockey Stick and the Climate Wars: Dispatches from the Front Lines by Michael E. Mann

Price: US$18.22; Kindle US$9.99; NZ$33.34
Hardcover: 384 pages
Publisher: Columbia University Press (March 6, 2012)
Language: English
ISBN-10: 023115254X
ISBN-13: 978-0231152549

Most readers have watched nature programmes hosted by David Attenborough. So you are familiar with scenes where predators will work together to target a single animal in a herd. If they can isolate it they will usually make a kill. If not they will go hungry.

You have seen it with Arctic wolves attacking oxen and African lions attacking zebras. Over recent years we have also seen it with politicians attacking climate scientists.

Michael Mann calls this the “Serengeti strategy:”

It “is a tried-and-true tactic of the climate change denial campaign. The climate change deniers isolate individual scientists just as predators on the Serengeti Plain of Africa hunt their prey: picking off vulnerable individuals from the rest of the herd.”

Mann is an authority on this phenomena – he has seen it from the inside, as a victim, for over a decade. Now he has written up his experiences, and the lessons drawn from them, in this new book appropriately called “The Hockey Stick and the Climate Wars.”

The “Hockey Stick”

In a sense Mann was a inadvertent victim of the climate denier campaign. His work had more to do with natural climate variation than human caused effects. As he puts it: “I felt that natural climate variability might be more important than some scientists thought. Indeed, it was that very assumption that motivated my Ph.D. research topic.” But in the process of researching the history of past climate changes, earth’s paleoclimate, he produced an “icon” of the climate change wars – the “Hockey Stick.” This research was included in the 2001 IPCC Report – and the “Hockey Stick” image, a record of the global and hemispheric temperature record over the last  600 years (in its original form), made it into the Summary for policy makers.

The personalisation of attacks on Mann over the “Hockey Stick” was also misplaced because he was not making any claim about human causes of global warming:

” I was always very careful not to claim that our work could firmly establish a human role in the warming. To draw such a conclusion based on our work alone would necessarily buy into the classic logical fallacy of “correlation without causation.” We had established correlation—the anomalous warming that we documented coincided with the human-caused ramp-up in greenhouse gas concentrations—but we hadn’t established causality.”

Mann’s record was based on proxy measurements (estimations of temperature from tree rings, ice cores, etc.), as well as, for more recent times, instrumental measurements. It did show changes attributable to natural events – which you would think would make the deniers happy. But it also showed very graphically, the global warming that has occurred over the last half century. This appeared to be quite anomalous over the last 1000 years. In fact, it was most likely to be greater than that which had occurred during the so-called “Medieval Warm Period.” The deniers could not forgive Mann for that finding – they had worked hard to convey the impression that global temperatures were actually higher then than they are today. (To some extent deniers have relied on regional temperature estimates – Mann’s estimate are for hemispherical and global temperatures). The iconic “Hockey Stick” threatened the climate denier’s icon – The Medieval Warm Period!

The McKittrick/McIntyre attack

The book describes controversy around The Hockey Stick – some of it based on genuine science, some derived from contrarian and denier attacks often financed by the fossil fuel industry.

One attack, much quoted by climate change deniers and contrarians, is that of  right-wing economist Ross McKittrick and Stephen McIntyre (a self described “semi-retired minerals consultant” with close ties to the energy industry). Published in a then controversial journal Energy and Environment it claimed Mann  had made fundamental mistakes in his statistical procedures. Their own analysis could not reproduce the “blade” of the hockey stick – that is no recent warming could be found in the data.

As Mann explained, this was a result of their own faulty analysis and their mistake was pointed out in subsequent published and refereed replies. Inevitably Mann’s description of the statistical analysis is technical and may be beyond some readers. But he has worked hard to make his description understandable and it is worth persisting because so much undeserved credit has been placed on McKintrick and MacIntyre’s paper. The scientific rejection of their work has of course not stopped the deniers who till this day claim that the M&M paper had discredited The Hockey Stick.

This work was used to denounce Mann’s work in the US House of Representatives. Republic Joe Barton, then head of the House Energy and Commerce Committee, launched a specific investigation of Mann’s work. (Joe Barton became well known five years later for his infamous apology to British petroleum over the fact that the Obama administration was holding it accountable for the oils spill the the Gulf of Mexico).

 Mann describes the political manoeuvring that went on around this House investigation. Particularly useful is his description of the Wegman report, set up by Barton to vindicate the work of McKintrick and McIntyre. It is constantly quoted by climate change contrarians – despite the fact that this report, and other work by Wegman and his students, has been criticised for plagiarism.

However Barton got a lot of political flack for his anti-science manoeuvring and Sherwood Boehlert, Republican chair of the Science Committee, commissioned the US National Academy of science to review the science behind the Hockey Stick. Their authoritative report Surface Temperature Reconstructions for the Last 2,000 Years largely vindicated Mann. Of course, have a read of climate denial books like Ian Wishart’s Air Con and you will find no mention of National Academy Report – only the Wegman’s report is used to perpetuate the lie that Man’s work was found  faulty (see my review of Wishart’s book – Alarmist con).

And, as Mann points out his work has been validated by over a dozen other independent reconstructions of the paleoclimate temperature record.

I have previously discussed the way climate change deniers have lied about the Hockey Stick in Climate change deniers’ tawdry manipulation of “hockey sticks”.

“Climategate” emails

Several times in this book Mann outlines the scientific approach to understanding reality. He uses the term “good faith science” – I think it is rather descriptive in this situation. Scientists welcome good faith criticism – doubt and scepticism are central to the scientific process. But the “scepticism” and attacks on climate science by vested interests and contrarians is quite different. It is not a “good faith” criticism. It is motivated, distorted, cherry picked and very often dishonest criticism. The so-called “climategate scandal” typifies this approach. Stolen emails between climate scientists were cherry picked  in an attempt to discredit the science.

The climate denier frenzy, and the investigations which cleared the scientists involved of any wrong-doing are now history. But scientists in general were rather taken aback by all this. They started to pay attention to these and other anti-science campaigns and debated the need to be proactive in communicating their science and combating the distortions and attacks.

Cuccinelli witchhunt

I think the recent legal attempts by Virginia Attorney General, Kenneth Cuccinelli, to get correspondence and emails relating to Mann and his research are one of the worst acts of the climate denial movement. Because it smacks of McCarthyism. Cuccinelli was on a “fishing trip” – which required him to assert that Mann was guilty of fraud – without any evidence.  Like the McCarthy persecution this sort of mud sticks and its aim was obviously to intimidate scientists.

After a prolonged legal battle the Virginia Supreme Court has now ruled that Mann’s documents cannot be subpoenaed by Cuccinelli (see The chickens are hatching). But his attempted precipitated action from scientific bodies in  defence of Mann and other scientists victimised by such persecution.

A positive conclusion

This book concentrates on Mann’s story. His research and the resulting attacks and persecution by the climate change denial political machine. It has valuable information debunking the denier mythology created around the “Hockey Stick.” There are also interesting background details clarify things like the strange position taken by the Institute of Physics at the UK parliamentary investigation of the climategate email issue (see Institute of Physics in hot seat).

But don’t expect new information on the funding of the climate denial network and links with the fossil fuel industry and politicians. Mann relies on the excellent  research of others here – and references the books Doubt is Their Product by David Michaels and Merchants of Doubt, by Oreskes and Conway.

Apart from the valuable background history the book provides I think its main value is the positive spin it provides, particularly in the final chapters. These discuss the reaction of climate scientists, and scientists in general, to the attacks on the science and the profession. The final straw appears to have come with the McCarthyist political attacks on Mann and other climate scientists. As Mann describes it – the bear has awoken. Scientists are finally recognising they cannot continue to ignore these attacks,. They are starting to fight back.

“The attacks against climate scientists by politicians like Senator James Inhofe and Virginia Attorney General Ken Cuccinelli were now being identified by prominent media outlets for the witch hunts they were. . . . I believe that the climategate attacks represented a turning point for my fellow climate scientist colleagues and how they viewed their role in the public debate. These latest attacks will fade from memory, and new ones will undoubtedly be launched to take their place. But I suspect that the change in heart among climate scientists regarding their role in the debate will be enduring.”

The book is also a good read. For anyone interested in the subject, with a bit of background knowledge, Mann’s reiteration of the public events, together with his knowledge of what was going on behind the scenes, makes the book a real page turner.

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In the front lines of the “climate wars”

Here’s another book to look out for – The Hockey Stick and the Climate Wars: Dispatches from the Front Lines. It will be published at the beginning of March .

The author, Michael Mann,  has been a central figure in the “climate wars.” His research into paleoclimate has been a particular target for climate sceptics/contrarians/deniers. And despite their claims that his work was discredited it has in fact been supported and replicated by other climate scientists. It also received endorsement from the The National Research Council of the US National Academies. (See and download Surface Temperature Reconstructions for the Last 2,000 Years (2006) )

Publisher’s description of book

This is how the publisher describes the book:

“In its 2001 report on global climate, the Intergovernmental Panel on Climate Change of the United Nations prominently featured the “Hockey Stick,” a chart showing global temperature data over the past one thousand years. The Hockey Stick demonstrated that temperature had risen with the increase in industrialization and use of fossil fuels. The inescapable conclusion was that worldwide human activity since the industrial age had raised CO2 levels, trapping greenhouse gases in the atmosphere and warming the planet.

“The Hockey Stick became a central icon in the “climate wars,” and well-funded science deniers immediately attacked the chart and the scientists responsible for it. Yet the controversy has had little to do with the depicted temperature rise and much more with the perceived threat the graph posed to those who oppose governmental regulation and other restraints to protect our environment and planet. Michael E. Mann, lead author of the original paper in which the Hockey Stick first appeared, shares the real story of the science and politics behind this controversy. He introduces key figures in the oil and energy industries, and the media front groups who do their bidding in sometimes slick, bare-knuckled ways to cast doubt on the science. Mann concludes with an account of the “Climategate” scandal, the 2009 hacking of climate scientists’ emails. Throughout, Mann reveals the role of science deniers, abetted by an uninformed media, in once again diverting attention away from one of the central scientific and policy issues of our time.”

McCarthyist attacks on science

Henry Waxman, Democratic member of the U.S. House of Representatives, former chairman of the House Energy and Commerce Committee said this of Michael Mann:

“As one of the nation’s leading climate researchers, no one has felt the brunt of the attacks from politicians and the fossil fuel industry more than Michael Mann. This is his personal account from the center of the maelstrom, documenting the lies and distortions about his work and his heroic efforts to stand up for scientific truth.”

Mann has certainly been one of the most high profile victim of the current McCarthyist attacks on climate science and scientists. This still continues. But he is not the only target. This has become such a problem that A Legal Defense Fund for Climate Scientists has been set up. You can find out more about the fund at its new web site and its recent press release –  Climate Science Legal Defense Fund Gets New Backing. As the press release says:

“The fund is designed to help scientists like Professor Michael Mann cope with the legal fees that stack up in fighting attempts by climate-skeptic groups to gain access to private emails and other correspondence through lawsuits and Freedom of Information Act requests at their public universities.”

The fund will also:

“Educate researchers about their legal rights and responsibilities on issues surrounding their work;

Serve as a clearinghouse for information related to legal actions taken against scientists; and

Recruit and assist lawyers representing these scientists.”

Another important  book to look forward to.

Climate change deniers’ tawdry manipulation of “hockey sticks”

Warning: This post abounds in “hockey sticks.”

Poneke’s recent blog post, 13 years of Climategate emails show tawdry manipulation of science by a powerful cabal at the heart of the global warming campaign, precipitated a lively discussion. Well, perhaps “discussion” is too kind because it was dominated by extreme deniers.

Now, I don’t want to label people unjustly. I respect those who are sceptical of the IPCC climate change conclusions, but are willing to stick with the science in discussing them. I reserve the term “deniers” for those irrational souls who grab at anything they can (cold days, snow, 1998 temperatures, IPCC mistake on Himalyan glaciers, etc., etc.). No interest in the science – just in using “sciencey” claims to advance their preconceived conclusions.

But my point in this post is to deal with one of Poneke’s claims which is demonstratively untrue.

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