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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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John Cook

John Cook is a research assistant professor at the Center for Climate Change Communication at George Mason University. He obtained his PhD at the University of Western Australia, studying the cognitive psychology of climate science denial. His research focus is understanding and countering misinformation about climate change. In 2007, he founded Skeptical Science, a website which won the 2011 Australian Museum Eureka Prize for the Advancement of Climate Change Knowledge and 2016 Friend of the Planet Award from the National Center for Science Education. John authored the book Cranky Uncle vs. Climate Change, that combines climate science, critical thinking, and cartoons to explain and counter climate misinformation. He also co-authored the college textbooks Climate Change: Examining the Facts and Climate Change Science: A Modern Synthesis and the book Climate Change Denial: Heads in the Sand. In 2013, he published a paper finding 97% scientific consensus on human-caused global warming, a finding that has been highlighted by President Obama and UK Prime Minister David Cameron.


Books, Booklets, Textbooks & Dissertation

Cook, J. (2020). Cranky Uncle vs. Climate Change: How to Understand and Respond to Climate Science DeniersNew York, NY: Citadel Press.

Cook, J. (2016). Closing the “consensus gap” by communicating the scientific consensus on climate change and countering misinformation. (Doctoral dissertation, University of Western Australia).

Bedford, D., & Cook, J. (2016). Climate Change: Examining the FactsSanta Barbara, CA: ABC-CLIO.

Farmer, G. T. & Cook, J. (2013). Climate Change Science: A Modern Synthesis. Dordrecht, Netherlands: Springer Science+Business Media.

Cook, J., & Lewandowsky, S. (2011). The Debunking Handbook. St. Lucia, Australia: University of Queensland. ISBN 978-0-646-56812-6. Available at

Washington, H. & Cook, J. (2011). Climate Change Denial: Heads in the Sand, Earthscan, Oxford, UK.

Cook, J. (2010). The Scientific Guide to Global Warming Skepticism, Cook, J.,

Book Chapters

Cook, J. (in press). Deconstructing Climate Science Denial. In Holmes, D. & Richardson, L. M. (Eds.) Edward Elgar Research Handbook in Communicating Climate Change. Cheltenham: Edward Elgar.

Cook, J. (in press). Consensus on Consensus: Countering Misinformation Targeting Expert Agreement on Climate Change. World Science Encyclopedia of Climate Change: Finance, Economics and Policy. World Scientific.

Winkler, B., Rice, K., Lubitz, T., & Cook, J. (in press). Skeptical Science. World Science Encyclopedia of Climate Change: Finance, Economics and Policy. World Scientific.

Cook, J. (2019). Chapter 9 : Is Emphasising Consensus In Climate Science Helpful For Policymaking? YES : Failure to communicate consensus leaves the public vulnerable to misinformation. In Hulme, M. (Ed.) Contemporary Climate Change Debates: A Student Primer. Abingdon, UK: Routledge

Cook, J. (2019). Understanding and countering misinformation about climate change. In Samoilenko, S., & Chiluwa, I. (Eds.), Handbook of Research on Deception, Fake News, and Misinformation Online (pp. 281-306). Hershey, PA: IGI-Global.

Cook, J. (2019). Turning climate misinformation into an educational opportunity. In J. C. Fessmann (Ed.), Strategic Climate Change Communications: Effective Approaches to Fighting Climate Denial (pp. 27-44). Wilmington, DE: Vernon Press.

Cook, J. (2016). Countering climate science denial and communicating scientific consensus. In M. Nisbett (Ed.), Oxford Encyclopedia of Climate Change Communication. London: Oxford University Press.

Cook, J. (2014). How Has the Carbon Tax Affected the Public ‘Debate’ on Climate Change? Quiggin, J., Adamson, D., & Quiggin, D. (Eds.), In Carbon Pricing: Early Experience and Future Prospects (pp. 49-64). Cheltenham Glos: Edward Elgar Publishing.

Journal Articles

Compton, J., van der Linden, S., Cook, J., & Basol, M. (in review). Inoculation Theory and Science Communication: New Avenues for Persuasion Research. Annals of the International Communication Association.

Vraga, E. K., Kim, S. C., & Cook, J. (2019). Testing Logic-based and Humor-based Corrections for Science, Health, and Political Misinformation on Social Media. Journal of Broadcasting & Electronic Media63(3), 393-414.

Lewandowsky, S., Cook, J., Fay, N., & Gignac, G. E. (2019). Science by Social Media: Attitudes Towards Climate Change are Mediated by Perceived Social ConsensusMemory & Cognition.

Cook, J. (2018). Understanding and countering climate science denial. Journal & Proceedings of the Royal Society of New South Wales150(2), 207–219. 

Cook, J., Ellerton, P., and Kinkead, D. (2018). Deconstructing climate misinformation to identify reasoning errors. Environmental Research Letters11(2).

Cook, J., Winkler, B., Finn, C., & Dodgen, T. (2017, January). Challenges and learning opportunities in a controversial MOOC forum on climate science denial. In 10th International Conference of Education, Research and Innovation (Iceri2017) (pp. 3460-3468). IATED Academy.

Lewandowsky, S., Ecker, U. K., & Cook, J. (2017). Letting the Gorilla Emerge From the Mist: Getting Past Post-Truth. Journal of Applied Research in Memory and Cognition6(4), 418-424.

van der Linden, S., Maibach, E., Cook, J., Leiserowitz, A., Lewandowsky, S. (2017). Inoculating against misinformation. Science, 358(6367), 1141-1142.

Lewandowsky, S., Ecker, U. K., & Cook, J. (2017). Beyond Misinformation: Understanding and Coping with the “Post-Truth” Era. Journal of Applied Research in Memory and Cognition6(4), 353-369.

Cook, J. (2017). Response by Cook to “Beyond Counting Climate Consensus. Environmental Communication, 1-3.

van der Linden, S., Maibach, E., Cook, J., Leiserowitz, A., Ranney, M., Lewandowsky, S., Árvai, J., & Weber, E. U. (2017). Culture versus cognition is a false dilemma. Nature Climate Change7(7), 457-457.

Cook, J., Lewandowsky, S., & Ecker, U. (2017). Neutralizing misinformation through inoculation: Exposing misleading argumentation techniques reduces their influence. PLOS ONE, 12(5): e0175799.

Skuce, A. G., Cook, J., Richardson, M., Winkler, B., Rice, K., Green, S. A., ... & Nuccitelli, D. (2017). Does It Matter if the Consensus on Anthropogenic Global Warming Is 97% or 99.99%? Bulletin of Science, Technology & Society, 0270467617702781.

Cook, J. (2017). How to Effectively Debunk Myths About Aging and Other Misconceptions. Public Policy and Aging Report27(1), 13-17. doi: 10.1093/ppar/prw034

Lewandowsky, S., Cook, J., & Lloyd, E. (2016). The `Alice in Wonderland' Mechanics of the Rejection of (Climate) Science: Simulating Coherence by Conspiracism, Synthese195(1), 175-196.

Cook, J., Oreskes, N., Doran, P. T., Anderegg, W. R. L., Verheggen, B., Maibach, E. W., Carlton, J.S., Lewandowsky, S., Green, S. A., Skuce, A. G., Nuccitelli, D., Jacobs, P., Richardson, M., Winkler, B., Painting, R., Rice, K. (2016). Consensus on consensus: a synthesis of consensus estimates on human-caused global warming. Environmental Research Letters11(4), 048002.

Cook, J. & Lewandowsky, S. (2016). Rational Irrationality: Modeling Climate Change Belief Polarization Using Bayesian Networks. Topics in Cognitive Science8(1), 160-179.

Cook, J., & Cowtan, K. (2015). Reply to Comment on ‘Quantifying the consensus on anthropogenic global warming in the scientific literature’Environmental Research Letters10(3), 039002.

Cook, J., Ecker, U. & Lewandowsky, S. (2015). Misinformation and how to correct it, Emerging Trends in the Social and Behavioral Sciences. Robert Scott and Stephen Kosslyn (Eds.), Hoboken, NJ: John Wiley and Sons.

Benestad, R. E., Nuccitelli, D., Lewandowsky, S., Hayhoe, K., Hygen, H. O., van Dorland, R., & Cook, J. (2015). Learning from mistakes in climate researchTheoretical and Applied Climatology, 1-5.

Lewandowsky, S., Cook, J., Oberauer, K., Brophy, S., Lloyd, E. A., & Marriott, M. (2015). Recurrent Fury: Conspiratorial Discourse in the Blogosphere Triggered by Research on the Role of Conspiracist Ideation in Climate Denial. Journal of Social and Political Psychology3(1), 142-178.

Abraham, J. P., Cook, J., Fasullo, J. T., Jacobs, P. H., Mandia, S. A. & Nuccitelli, D. A. (2014). Review of the Consensus and Asymmetric Quality of Research on Human-Induced Climate Change, Cosmopolis2014-1, 3-18.

Cook, J. & Jacobs, P. (2014). Scientists are from Mars, Laypeople are from Venus: An Evidence-Based Rationale for Communicating the Consensus on ClimateReports of the National Center for Science Education. 34, 6, 3.1-3.10.

Cook, J., Nuccitelli, D., Skuce, A., Way, R., Jacobs, P., Painting, R., Lewandowsky, S. & Coulter, A. (2014). 24 critical errors in Tol (2014): Reaffirming the 97% consensus on anthropogenic global warming.

Cook, J., Bedford, D. & Mandia, S. (2014). Raising Climate Literacy Through Addressing Misinformation: Case Studies in Agnotology-Based Learning. Journal of Geoscience Education, 62(3), 296-306.

Cook, J., Nuccitelli, D., Skuce, A., Way, R., Jacobs, P., Painting, R., Honeycutt, R., Green, S.A. (2014). Reply to Comment on ‘Quantifying the consensus on anthropogenic global warming in the scientific literature: a Reanalysis’. Energy Policy. DOI: 10.1016/j.enpol.2014.06.002

Verheggen, B., Strengers, B., Cook, J., van Dorland, R., Vringer, K., Peters, J., Visser, H. & Meyer, L. (2014). Scientists’ views about attribution of global warming. Environmental science & technology48(16), 8963-8971.

Bedford, D., & Cook, J. (2013). Agnotology, Scientific Consensus, and the Teaching and Learning of Climate Change: A Response to Legates, Soon and Briggs. Science & Education22(8), 2019-2030.

Cook, J., Nuccitelli, D., Green, S.A., Richardson, M., Winkler, B., Painting, R., Way, R., Jacobs, P., & Skuce, A. (2013). Quantifying the consensus on anthropogenic global warming in the scientific literature. Environmental Research Letters8(2), 024024+.

Lewandowsky, S., Ecker, U. K. H., Seifert, C. M., Schwarz, N., & Cook, J. (2012). Misinformation and its correction: Continued influence and successful debiasing. Psychological Science in the Public Interest13, 106-131.

Nuccitelli, D., Way, R., Painting, R., Church, J., & Cook, J. (2012). Comment on ocean heat content and Earth's radiation imbalance. II. Relation to climate shifts. Physics Letters A, 376(45), 3466-3468.

Massive Open Online Course (MOOC)

Cook, J., Schuennemann, K., Nuccitelli, D., Jacobs, P., Cowtan, K., Green, S., Way, R., Richardson, M., Cawley, G., Mandia, S., Skuce, A., & Bedford, D. (April 2015). Making Sense of Climate Science Denial. edX


Recent blog posts

The Debunking Handbook 2020: Debunk often and properly

Posted on 26 October 2020 by John Cook

This blog post is part 4 of a series of excerpts from The Debunking Handbook 2020 which can be downloaded here. The list of references is available here.

Debunk often and properly

dbh-oftenIf you cannot preempt, you must debunk. For debunking to be effective, it is important to provide detailed refutations 2, 3. Provide a clear explanation of (1) why it is now clear that the information is false, and (2) what is true instead. When those detailed refutations are provided, misinformation can be “unstuck.” Without detailed refutations, the misinformation may continue to stick around despite correction attempts.

Simple corrections on their own are unlikely to fully unstick misinformation. Tagging something as questionable or from an untrustworthy source is not enough in the face of repeated exposures.

Debunking is more likely to be successful if you apply the following 3 or 4 components:


FACT: State the truth first

If it’s easy to do in a few clear words, state what is true first. This allows you to frame the message—you lead with your talking points, not someone else’s.

The best corrections are as prominent (in the headlines, not buried in questions) as the misinformation.

Do not rely on a simple retraction (“this claim is not true”).



The Debunking Handbook 2020: References

Posted on 26 October 2020 by John Cook

This is the list of references for The Debunking Handbook 2020

Lewandowsky, S., Cook, J., Ecker, U. K. H., Albarracín, D., Amazeen, M. A., Kendeou, P., Lombardi, D., Newman, E. J., Pennycook, G., Porter, E. Rand, D. G., Rapp, D. N., Reifler, J., Roozenbeek, J., Schmid, P., Seifert, C. M., Sinatra, G. M., Swire-Thompson, B., van der Linden, S., Vraga, E. K., Wood, T. J., Zaragoza, M. S. (2020). The Debunking Handbook 2020. Available at

1 Johnson, H. M., & Seifert, C. M. (1994). Sources of the continued influence effect: When misinformation in memory affects later inferences. Journal of Experimental Psychology: Learning, Memory, and Cognition, 20(6), 1420-1436.

2 Ecker, U. K. H., O’Reilly, Z., Reid, J. S., & Chang, E. P. (2020). The effectiveness of short‐format refutational fact‐checks. British Journal of Psychology, 111(1), 36-54.

3 Paynter, J., Luskin-Saxby, S., Keen, D., Fordyce, K., Frost, G., Imms, C., ... & Ecker, U. K. H. (2019). Evaluation of a template for countering misinformation—Real-world autism treatment myth debunking. PLOS ONE, 14, e0210746. journal.pone.0210746.

4 Lewandowsky, S., Ecker, U. K. H., & Cook, J. (2017). Beyond misinformation: Understanding and coping with the post-truth era. Journal of Applied Research in Memory and Cognition, 6, 353-369.

5 Southwell, B. G., Thorson, E. A., & Sheble, L. (2018). Misinformation among mass audiences as a focus for inquiry. In B. G. Southwell, E. A. Thorson, & L. Sheble (Eds.), Misinformation and mass audiences (pp. 1–14). Austin: University of Texas Press.



The Debunking Handbook 2020: The elusive backfire effects

Posted on 22 October 2020 by John Cook

This blog post is part 3 of a series of excerpts from The Debunking Handbook 2020 which can be downloaded here. The list of references is available here.

The elusive backfire effects

Ten years ago, scholars and practitioners were concerned that corrections may “backfire”; that is, ironically strengthen misconceptions rather than reduce them. Recent research has allayed those concerns: backfire effects occur only occasionally and the risk of occurrence is lower in most situations than once thought.

Do not refrain from attempting to debunk or correct misinformation out of fear that doing so will backfire or increase beliefs in false information 66, 67, 68.


Backfire Effect: A backfire effect is where a correction inadvertently increases belief in, or reliance on, misinformation relative to a pre-correction or nocorrection baseline.

Familiarity backfire effect

Repetition makes information more familiar, and familiar information is generally perceived to be more truthful than novel information (the aforementioned illusory-truth effect). Because a myth is necessarily repeated when it is debunked, the risk arises that debunking may backfire by making a myth more familiar (see figure below). Early evidence was supportive of this idea, but more recently, exhaustive experimental attempts to induce a backfire effect through familiarity alone have come up empty 69, 70. Thus, while repeating misinformation generally increases familiarity and truth ratings, repeating a myth while refuting it has been found to be safe in many circumstances, and can even make the correction more salient and effective 71.

FamiliarityBackfireEffect “Debunking a myth makes it more familiar but the debunking usually overpowers the increase in familiarity.”



The Debunking Handbook 2020: Prevent misinformation from sticking if you can

Posted on 20 October 2020 by John Cook

This blog post is part 2 of a series of excerpts from The Debunking Handbook 2020 which can be downloaded here. The list of references is available here.

Prevent misinformation from sticking if you can

dbh-preventBecause misinformation is sticky, it’s best preempted. This can be achieved by explaining misleading or manipulative argumentation strategies to people—a technique known as “inoculation” that makes people resilient to subsequent manipulation attempts. A potential drawback of inoculation is that it requires advance knowledge of misinformation techniques and is best administered before people are exposed to the misinformation.

As misinformation is hard to dislodge, preventing it from taking root in the first place is one fruitful strategy. Several prevention strategies are known to be effective.

Simply warning people that they might be misinformed can reduce later reliance on misinformation 27, 78. Even general warnings (“the media sometimes does not check facts before publishing information that turns out to be inaccurate”) can make people more receptive to later corrections. Specific warnings that content may be false have been shown to reduce the likelihood that people will share the information online 28.

The process of inoculation or “prebunking” includes a forewarning as well as a preemptive refutation and follows the biomedical analogy 29. By exposing people to a severely weakened dose of the techniques used in misinformation (and by preemptively refuting them), “cognitive antibodies” can be cultivated. For example, by explaining to people how the tobacco industry rolled out “fake experts” in the 1960s to create a chimerical scientific “debate” about the harms from smoking, people become more resistant to subsequent persuasion attempts using the same misleading argumentation in the context of climate change 30.

The effectiveness of inoculation has been shown repeatedly and across many different topics 30, 31, 32, 33, 34. Recently, it has been shown that inoculation can be scaled up through engaging multimedia applications, such as cartoons 35 and games 36, 37.



The Debunking Handbook 2020: Misinformation is damaging and sticky

Posted on 16 October 2020 by John Cook

This blog post is part 1 of a series of excerpts from The Debunking Handbook 2020 which can be downloaded here. The list of references is available here.

Misinformation can do damage

DBH-damageMisinformation is false information that is spread either by mistake or with intent to mislead. When there is intent to mislead, it is called disinformation. Misinformation has the potential to cause substantial harm to individuals and society. It is therefore important to protect people against being misinformed, either by making them resilient against misinformation before it is encountered or by debunking it after people have been exposed.

Misinformation damages society in a number of ways 4, 5. If parents withhold vaccinations from their children based on mistaken beliefs, public health suffers 6. If people fall for conspiracy theories surrounding COVID-19, they are less likely to comply with government guidelines to manage the pandemic 7, thereby imperiling all of us.

It’s easy to be misled. Our feelings of familiarity and truth are often linked. We are more likely to believe things that we have heard many times than new information.

This phenomenon is called the “illusory truth effect” 8, 9. Thus, the more people encounter a piece of misinformation they do not challenge, the more the misinformation seems true, and the more it sticks. Even if a source is identified as unreliable or is blatantly false and inconsistent with people’s ideology, repeated exposure to information still tilts people towards believing its claims 10, 11, 12, 13.

Misinformation is also often steeped in emotional language and designed to be attention-grabbing and have persuasive appeal. This facilitates its spread and can boost its impact 14, especially in the current online economy in which user attention has become a commodity 15.

Misinformation can also be intentionally suggested by “just asking questions”; a technique that allows provocateurs to hint at falsehoods or conspiracies while maintaining a facade of respectability 16. For example, in one study, merely presenting questions that hinted at a conspiracy relating to the Zika virus induced significant belief in the conspiracy 16. Likewise, if you do not read past a headline such as “Are aliens amongst us?” you might walk away with the wrong idea.



The Debunking Handbook 2020: Downloads and Translations

Posted on 14 October 2020 by John Cook

DBH2020-EN-ThumbIn November 2011, we published The Debunking Handbook. As the update notice on that page already shows, more research has come in since then and the time had finally come for a complete overhaul of this very popular handbook (it still gets downloaded a couple of thousand times in most months!). The two authors of the original handbook - Stephan Lewandowsky and John Cook - got in touch with other researchers who look into how best to counter misinformation and 20 of them signed up as co-authors. The result of their work can now be downloaded as The Debunking Handbook 2020.

The handbook is a consensus document that was created by an innovative process that involved a series of predefined steps, all of which were followed and documented and are publicly available. The authors were invited based on their scientific status in the field, and they all agreed on all points made in the handbook. We therefore believe that the new Handbook reflects the scientific consensus about how to combat misinformation. Read more about the consensus process.

The Handbook distills the most important research findings and current expert advice about debunking misinformation and contains information about these topics available in four excerpts:

Part 1:

  • Misinformation can do damage
  • Where does misinformation come from?
  • Misinformation can be sticky
  • Sticky myths leave other marks

Part 2:

  • Prevent misinformation from sticking if you can
  • Simple steps to greater media literacy
  • The strategic map of debunking
  • Who should debunk?

Part 3:

  • The elusive backfire effects
  • Role of worldview in belief confirmation

Part 4:

  • Debunk often and properly
  • Collective action: Debunking on social media





Critical Thinking about Climate - a video series by John Cook

Posted on 5 October 2020 by John Cook

This is a collection of videos based on individual blog posts on John Cook's Cranky Uncle website. The videos are part of a virtual grad class “Understanding and Responding to Climate Misinformation” that John Cook is teaching at George Mason University with Natalie Burls & Tim DelSole. Their class teaches climate & communication students the climate & comm research needed to debunk climate misinformation.

Part 1 - The five climate disbeliefs

The five climate disbeliefs: a crash course in climate misinformation (27 minutes)

You can summarize climate change in just ten words: it's real, it's us, experts agree, it's bad, there's hope. Climate change misinformation is like a bizarro world version of this summarized with five categories: it's not real, it's not us, experts are unreliable, it's not bad, there's no hope. Understanding the arguments of climate denial is the first step to countering it. This video is a crash course in climate misinformation, summarizing the key arguments used to cast doubt on the reality of climate change and delay climate action.



How to debunk misinformation

Posted on 10 September 2020 by John Cook

An effective rebuttal requires three elements. Fact. Myth. Fallacy. This video to explain how to tie these together into a cohesive debunking.



The story of climate consensus

Posted on 2 September 2020 by John Cook

The scientific consensus on human-caused global warming has been a fierce topic for decades. To understand why, you need to know the history of consensus. The first message the public heard about the consensus on climate change was that there was no consensus. Next, scientists published a series of studies quantifying expert agreement on human-caused global warming – multiple studies found 90 to 100% agreement with multiple studies converging on 97% consensus. In response, climate deniers continued to argue there was no consensus (as well as argue scientists should stop talking about it because science isn’t done by consensus).



Cranky Uncle cartoons available as PPT slides

Posted on 10 August 2020 by John Cook

Since finishing the Cranky Uncle vs. Climate Change book, I’ve frequently dipped into that 176-page clip-art library, reshaping the cartoons to fit the 1920 x 1080 pixel format for Powerpoint presentations. I’ve also adapted many of the cartoons for the Cranky Uncle video series.

Over the last few weeks, a few people have asked if they could use some of my Cranky Uncle cartoons in their climate talks. In response, I’ve now collected a bunch of 1920 x 1080 Cranky Uncle cartoons and uploaded them all in a freely available Powerpoint presentation. Any educators, scientists, activists, or climate communicators giving a talk about climate change are welcome to use any of the cartoons in your talks. They are free to use (but letting us know the context of how you used them in the comment thread below would be much appreciated).


Almost all the cartoons come from the Cranky Uncle book with a few exceptions. One is a cartoon I drew of Scott Pruitt. This was actually in the first draft of the book, which I wrote back when Pruitt was head of the EPA. Pruitt actually featured quite a lot in that first draft – which I think was a way for me to cope with the frustration of the endless series of scandals following him. My editor wisely advised me to trim Pruitt from the book, suggesting it would date very quickly. Sure enough, Pruitt was fired before I even finished the first draft!

Another cartoon I drew after the book was finished was a cartoon I drew for a Guardian article by Dana Nuccitelli. As is usual for Dana, his article was excellent and went viral so that the article got featured on the Guardian homepage – which meant my cartoon appeared on the Guardian homepage for a short while. That was fun!



Coronavirus conspiracy theories are dangerous – here’s how to stop them spreading

Posted on 27 April 2020 by Stephan Lewandowsky

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The number of coronavirus infections and deaths continues to rise at an alarming rate, reminding us that this crisis is far from over. In response, the global scientific community has thrown itself at the problem and research is unfolding at an unprecedented rate.

The new virus was identified, along with its natural origins, and tests for it were rapidly developed. Labs across the world are racing to develop a vaccine, which is estimated to be still around 12 to 18 months away.

At the same time, the pandemic has been accompanied by an infodemic of nonsense, disinformation, half-truths and conspiracy theories that have spread virally through social networks. This damages society in a variety of ways. For example, the myth that COVID-19 is less dangerous than the seasonal flu was deployed by US president Donald Trump as justification for delaying mitigation policies.

The recent downgrading of COVID-19 death projections, which reveal the success of social-distancing policies, has been falsely used to justify premature relaxing of social distancing measures. This is the logical equivalent of throwing away your umbrella in a rainstorm because it’s kept you dry until then.


This article is part of the Expert guide to conspiracy theories, a series by The Conversation’s The Anthill podcast. Listen here, on Apple Podcasts or Spotify, or search for The Anthill wherever you get your podcasts.

The new conspiracy theory that blames COVID-19 on the 5G broadband system is one of the most bizarre pieces of misinformation. There are several strains of this theory, ranging from the claims that 5G alters people’s immune systems to the idea that 5G changes people’s DNA, making them more susceptible to infection. Then there’s the idea that secret messages about 5G and coronavirus were hidden in the design of the new £20 note in the UK. In reality, 5G relates to viruses and bank notes as much as the tooth fairy relates to zoology – not at all.

The 5G conspiracy theory originated in early March when an American physician, Thomas Cowan, proposed it in a YouTube video (which has since been taken down by YouTube according to their new policy). Some people have taken this conspiracy theory so seriously that it led to people setting 5G towers in the UK on fire and threatening broadband engineers.

The conspiracy theory has begun to penetrate mainstream society. Among other celebrities, UK TV personality Eamonn Holmes and US actor Woody Harrelson have given fuel to the idea.



A history of FLICC: the 5 techniques of science denial

Posted on 31 March 2020 by John Cook

In 2007, Mark Hoofnagle suggested on his Science Blog Denialism that denialists across a range of topics such as climate change, evolution, & HIV/AIDS all employed the same rhetorical tactics to sow confusion. The five general tactics were conspiracy, selectivity (cherry-picking), fake experts, impossible expectations (also known as moving goalposts), and general fallacies of logic.

Two years later, Pascal Diethelm and Martin McKee published an article in the scientific journal European Journal of Public Health titled Denialism: what is it and how should scientists respond? They further fleshed out Hoofnagle’s five denialist tactics and argued that we should expose to public scrutiny the tactics of denial, identifying them for what they are. I took this advice to heart and began including the five denialist tactics in my own talks about climate misinformation.

In 2013, the Australian Youth Climate Coalition invited me to give a workshop about climate misinformation at their annual summit. As I prepared my presentation, I mused on whether the five denial techniques could be adapted into a sticky, easy-to-remember acronym. I vividly remember my first attempt: beginning with Fake Experts, Unrealistic Expectations, Cherry Picking… realizing I was going in a problematic direction for a workshop for young participants. I started over and settled on FLICC: Fake experts, Logical fallacies, Impossible expectations, Cherry picking, and Conspiracy theories.

When I led a 2015 collaboration between the University of Queensland and Skeptical Science to develop the free online course Denial101x: Making Sense of Climate Science Denial, we made FLICC the underlying framework of the entire course. An important component of our debunking of the most common myths about climate change was identifying the denial techniques in each myth. A common comment we received from students was how much they appreciated learning about FLICC.



Upcoming Cranky Uncle events

Posted on 25 February 2020 by John Cook

The Cranky Uncle vs. Climate Change book is now available! The book uses cartoons, humor, and critical thinking to expose how and why some people reject climate science. It's now available for sale on Amazon, Barnes & Noble, and other book outlets.

Cranky Uncle vs Climate Change cover

If you're near the DC area, you're very welcome to attend our launch event at the George Mason University Arlington campus on March 4. I'll be talking about how my psychological and critical thinking research was applied in the creation of this book, and will be signing books afterwards. There'll also be some limited edition Cranky Uncle swag for some lucky attendees! You can register for this free event here.



How deniers maintain the consensus gap

Posted on 18 February 2020 by John Cook

An excerpt from the book Cranky Uncle vs. Climate Change, released Feb 25. First posted here.

A number of studies have quantified the level of scientific agreement on climate change. In 2009, a survey by Peter Doran found that 97.4% of publishing climate scientists agreed that humans were changing global temperature. In 2010, Bill Anderegg analyzed public statements about climate change. He found 97–98% agreement among the most actively publishing climate scientists that humans are causing global warming.

In 2013, I led a team of researchers analyzing 21 years of scientific papers about global warming. Among relevant climate papers, 97% affirmed the consensus. Three different studies all found overwhelming scientific agreement.

The scientific consensus has also been endorsed by many scientific organizations around the world, such as the American Geophysical Union, European Geosciences Union, Royal Meteorological Society, and Australian Bureau of Meteorology. The National Academies of Science from eighty countries have all affirmed human-caused global warming.

Deniers argue that there’s no scientific consensus on climate change because thirty-one thousand science graduates signed a petition rejecting the consensus. This argument appeals to fake experts. The only requirement for the Petition Project is an undergraduate degree in any kind of science. Only 0.1% of the signatories are climate scientists. Asking for nonexpert opinion on a complex topic is like asking a computer scientist to perform heart surgery.



Climate goes extreme!

Posted on 13 February 2020 by John Cook

An excerpt from the book Cranky Uncle vs. Climate Change, released Feb 25.

Every weather event is affected in some way by global warming, including the buildup of heat, more moisture in the atmosphere, and rising sea levels. A direct impact of the extra heat is more intense and frequent heatwaves.

Warming also accelerates evaporation of water from the ground and water sources. As the ground dries out, drought intensifies and fire danger increases. Extra evaporation also puts more moisture into the atmosphere, and warmer air can hold more water vapor. Both these factors result in heavier downpours. The warmer oceans also provides additional energy for hurricanes, making them more intense.

Weather is somewhat unpredictable, like rolling dice. Global warming increases the occurence and/or strength of many types of extreme weather. It’s like drawing extra dots on the dice, increasing the odds of a higher roll.

People often ask: “Was a specific weather event caused by climate change?” That’s the wrong question. A more appropriate question is: “Are weather events being affected by climate change?” The answer is yes, global warming is increasing the occurence and/or strength of extreme weather. As NOAA climate scientist Deke Arndt says, "weather throws the punches, but climate trains the boxer."



On climate misinformation and accountability

Posted on 10 February 2020 by dana1981

Lately there has been a great deal of misinformation regarding the origins and purpose of Skeptical Science.  As John Cook wrote nearly a decade ago, Skeptical Science is primarily a website that debunks climate misinformation with peer-reviewed science.  Despite the ever-worsening impacts from climate change, with record after record being broken in our warming climate, misinformation casting doubt on climate science is rampant and showing no signs of going away. Sadly, a resource that shines disinfecting daylight on climate misinformation is needed more than ever.

When we find ourselves frequently debunking myths from the same sources, we collect that information in our 'Misinformation by Source' database. There are several reasons why we created that particular database. 

First, because we at Skeptical Science simply love data.  That's the backbone of our website.  We love to gather it, analyze it, and organize it for easy reference. One of the strengths of our site is making our debunkings accessible in different ways for ease-of-use, such as our multi-level rebuttals, translations, short URLs for easy sharing, and organized in a fact-myth-fallacy format.

Second, for the sake of accountability.  If an individual propagates a climate myth to the public via a setting like a blog or media interview or congressional testimony, it's useful to have a resource documenting if that individual has frequently promoted climate myths in the past.  If so, that individual should be considered a relatively unreliable source of accurate climate science information. 

To those who object to being included on the 'Misinformation by Source' database, the remedy is simple – stop purveying climate myths.  Perhaps acknowledge the mistakes you made in communicating those myths.  Take responsibility for your own actions.



Why is the Keeling curve so curvy?

Posted on 4 February 2020 by John Cook

An excerpt from the book Cranky Uncle vs. Climate Change, released Feb 25.

In 1958, Charles Keeling began measuring atmospheric carbon dioxide (CO2) levels in Mauna Loa, Hawaii. He found CO2 rising and falling from year to year. This graph became known as the Keeling Curve.

This yearly cycle is due to CO2 moving between the atmosphere and vegetation. In spring, plants convert CO2 into foliage. In autumn, the leaves fall and rot, emitting CO2 into the atmosphere.

Keeling also found that over time, the amount of CO2 in the air was increasing. All our fossil fuel burning is causing a rise in atmospheric CO2.



Global warming is happening here and now

Posted on 28 January 2020 by John Cook

An excerpt from the book Cranky Uncle vs. Climate Change, released Feb 25.

Signs of global warming are being observed all over our planet. Thermometers measure surface warming. Buoys sunk to ocean depths measure heat building up in our oceans. Ice is melting across our planet, with ice sheets crumbling and glaciers retreating. Spring is coming earlier. Sea levels are rising. Species are migrating to flee warming temperatures. Even tree lines are shifting!

Over the last century and a half, our planet has warmed around 1°C. This involves a huge amount of heat, with negative impacts all over our planet. But locally, we experience tens of degrees of temperature change every day, so one degree doesn’t seem like much. Like frogs in a pot slowly coming to a boil, we find the severity of global warming difficult to grasp.

The notion that global warming is some far-off, distant threat is an insidious but prevalent misconception. It arises in part from the way we maintain psychological distance from our fears. We think of something as psychologically distant if we’re not directly experiencing it.

Psychological distance manifests in different forms—thinking that global warming is happening in the distant future, that it’s happening in far-off places (this misconception perpetuated by clichéd images such as polar bears), that climate impacts are hypothetical and uncertain, and that the impacts are happening to communities different from us.



How did climate change get so controversial?

Posted on 21 January 2020 by John Cook

An excerpt from the book Cranky Uncle vs. Climate Change, released Feb 25.

Our human brain is poorly equipped to deal with a threat like climate change. Over millions of years, we’ve evolved to avoid life-threatening dangers like predators jumping out of bushes. We’ve survived by quickly detecting and avoiding immediate, short-term dangers.

In contrast, global warming is a slow-motion disaster happening on a global scale. Our brains aren’t built to respond to planetary crises stretched out over a lifetime. It should come as no surprise that people have trouble appreciating just how dangerous climate change is.

Predators vs. scientific data

On top of all these difficulties, we are also being hit with a massive wave of misinformation about climate change. Vested interests, political polarization, the global nature of climate change, and misinformation combine to form a perfect psychological storm, preventing people from accepting climate science and supporting climate action.

Climate change: a psychological perfect storm

From the public’s point of view, the tsunami of misinformation looks like scientific controversy. We hear experts and contrarians on TV or social media spouting jargon and assume scientists are still undecided on basic questions, like whether humans are causing global warming.

This veneer of controversy conceals the fact that our scientific understanding of human-caused global warming is built on more than a century of research. Scientific confidence is strongest when many different lines of evidence all point to a single conclusion. That’s what we observe with climate change. 



Cranky Uncle crowdfunding campaign launches!

Posted on 3 December 2019 by John Cook

Cranky Uncle Matching Gift! We're closing in on our stretch goal to fund Cranky Uncleas an Android app. $6,000 will finish this stretch goal. To get us over the line, two anonymous contributors have agreed to match other contributions until midnight of December 31st, dollar for dollar up to $3,000, taking us past the post. Double your impact by contributing right now while you're thinking about it! To all those who've already contributed, a huge Thank You! 

We've just launched our crowdfunding campaign to develop the Cranky Uncle smartphone game. The purpose of this free game is to teach resilience against misinformation. We've already tested the game in college classes across the country, finding it increases students' ability to detect reasoning fallacies in misinformation across a range of topics. You can donate to help turn our game into reality at the Cranky Uncle Crowdfunding Page.

Lest I bury the lede, I should mention the most time-sensitive element of our crowdfunding campaign: I'm going to personally draw the first 97 early birds who donate $250 or more in our Giving Tuesday event. These cartoons will be an integral part of the game, used in critical thinking quiz questions that help players practice spotting logical fallacies in false arguments. But I'm only offering this reward to the first 97 Cameo donors because I have to draw you all myself and there are only so many hours in the day! Here's what the process looks like (starring Brendan deMelle from Desmogblog):



Harnessing gamification to defeat climate misinformation

Posted on 26 November 2019 by John Cook

For the past decade, I've been researching the psychology of climate denial, exploring ways to counter misinformation about climate change. I came out of my PhD with inoculation as a powerful solution. After completing my PhD, I explored critical thinking as a tool to help develop inoculating messages.

One of the most intriguing leads from my critical thinking work was the potential of parallel arguments. This involves taking the flawed reasoning in misinformation and transplanting it into an absurd situation, making the logical fallacy more obvious. A lightbulb moment for me was realizing that this technique was used every night by late night comedians to debunk the misinformation of the day, in a way that was both entertaining and instructive.

Having worked as a cartoonist before my PhD, I immediately saw that cartoons were the perfect delivery mechanism for parallel arguments. So for the last two years, I've been experimentally testing parallel arguments as a means of countering misinformation on social media. Not only has this research shown that my funny is statistically significant (yes, that was the first thing I checked after data collection), we have also shown that parallel arguments in cartoon form are effective in neutralizing misinformation.



Consensus on consensus hits half a million downloads

Posted on 2 September 2019 by John Cook

In 2013, the Skeptical Science team published a study in Environmental Research Letters finding 97% scientific consensus on human-caused global warming. However, we weren't the first researchers to find overwhelming scientific consensus, nor were we the last. In 2016, we teamed up with authors of six other consensus studies to publish Consensus on consensus: a synthesis of consensus estimates on human-caused global warming. This week, our Consensus on Consensus study just went past 500,000 downloads.

half mil

Replication is the heart of the scientific method. When multiple scientific studies, using independent methods, all arrive at similar conclusions, we become more confident that our scientific understanding is correct. This is why scientists are so confident that humans are causing global warming: multiple lines of evidence all find human fingerprints in climate change. In the same way, we know there is a scientific consensus because multiple studies independently find overwhelming scientific agreement that humans are causing global warming.

So I was always bemused by the fact that our 2013 consensus study received so many attacks, as if this would singlehandedly overturn the 97% consensus on human-caused global warming. This sentiment is most explicitly articulated by Senator Ted Cruz who argued that the 97% consensus was based "on one bogus study." The simplest retort to this argument is that the 97% consensus has been confirmed by multiple studies, including Doran & Zimmerman 2009, Anderegg et al 2010, and Carlton et al. 2015.



The consensus on consensus messaging

Posted on 7 August 2019 by John Cook

A scientist would never tolerate statements about climate change that weren't based on scientific research and empirical evidence. However, the same evidentiary standards don't always seem to apply to statements about how to communicate about climate change. For example, on the topic of communicating the scientific consensus on human-caused global warming, there are lots of opinions on whether communicating the scientific consensus is effective or not. Many of these opinions are not based on the body of empirical research into consensus messaging. 



97% consensus study hits one million downloads!

Posted on 17 July 2019 by John Cook

Our 2013 study Quantifying the consensus on anthropogenic global warming in the scientific literature just hit one million downloads! This makes it the #1 most downloaded paper at the journal Environmental Research Letters. In fact, it's the most downloaded paper in the 80+ journals published by the Institute of Physics. One million+ downloads are usually reserved for viral videos involving piano-playing cats. Not a bad effort for a peer-reviewed scientific paper!



Skeptical Science takes the Pro-Truth-Pledge

Posted on 7 January 2019 by BaerbelW

Skeptical Science has been fighting misinformation about human-caused climate change since the website was launched in 2007. But with the rise in prevalence of fake news over the last few years, protecting truth and facts has become more important than ever. To help with that task, some additional means by which to distinguish between truth-tellers and those who spread misinformation would be useful to have. This is where the Pro-Truth-Pledge comes in.


The Pro-Truth-Pledge (website: has been established in order to reclaim the fuzzy concept of "truth," which different people may interpret differently.  It gives a much stricter definition, outlined by the following twelve clearly-observable behaviors that research in behavioral science shows correlate with truthfulness:



Upcoming webinars on turning misinformation into an educational opportunity

Posted on 27 July 2018 by John Cook

Since starting Skeptical Science in 2007, I've been researching how to counter misinformation.  One answer is inoculation - you can neutralize misinformation by exposing people to a "weak form of misinformation" (e.g., explain the techniques used to mislead). But how do we put this into practice?

One of the most powerful ways to teach science and counter science denial is in the classroom through misconception-based learning. I've been lucky enough to collaborate with several organizations to provide educational resources using this approach. The Skeptical Science team worked with UQx to develop the online course Making Sense of Climate Science Denial.

Now I'm based in the U.S., I've been lucky enough to collaborate with the National Center for Science Education and the Alliance of Climate Educators to develop a set of lesson plans teaching key facts about climate change while addressing five of the most common climate myths. With Brad Hoge (Director of Teacher Support at NCSE) and teachers from around the country who field-tested the lessons, we'll be presenting a five-part webinar series on how to teach our five lessons.

Each webinar will focus on a single NGSS-aligned lesson plan. You can sign up for free to any or all five to get the full complement of lessons. All participants will receive a certificate that can be used for continuing education units. The webinars will be at 7:00-8:30 pm Eastern Time via Zoom.

Register at 



Humans need to become smarter thinkers to beat climate denial

Posted on 6 February 2018 by dana1981

Climate myths are often contradictory – it’s not warming, though it’s warming because of the sun, and really it’s all just an ocean cycle – but they all seem to share one thing in common: logical fallacies and reasoning errors.

John Cook, Peter Ellerton, and David Kinkead have just published a paper in Environmental Research Letters in which they examined 42 common climate myths and found that every single one demonstrates fallacious reasoning. For example, the authors made a video breaking down the logical flaws in the myth ‘climate changed naturally in the past so current climate change is natural.’

Video abstract for paper “Deconstructing climate misinformation to identify reasoning errors” published in Environmental Research Letters by John Cook, Peter Ellerton, and David Kinkead.

Beating myths with critical thinking

Cook has previously published research on using ‘misconception-based learning’to dislodge climate myths from peoples’ brains and replace them with facts, and beating denial by inoculating people against misinformers’ tricks. The idea is that when people are faced with a myth and a competing fact, the fact will more easily win out if the fallacy underpinning the myth is revealed. In fact, these concepts of misconception-based learning and inoculation against myths were the basis of the free online Denial101x course developed by Cook and colleagues.



Why the 97% climate consensus is important

Posted on 2 October 2017 by dana1981

John Cook is a research assistant professor at the Center for Climate Change Communication at George Mason University, researching cognitive science.

Sander van der Linden is an Assistant Professor in Social Psychology, Director of the Cambridge Social Decision-Making Lab and a Fellow of Churchill College.

Anthony Leiserowitz is a Research Scientist and Director of the Yale Project on Climate Change at the School of Forestry and Environmental Studies at Yale University.

Edward Maibach is a University Professor and Director of Mason’s Center for Climate Change Communication.

Unfortunately, humans don’t have infinite brain capacity, so no one can become an expert on every subject. But people have found ways to overcome our individual limitations through social intelligence, for example by developing and paying special attention to the consensus of experts. Modern societies have developed entire institutions to distill and communicate expert consensus, ranging from national academies of science to the Intergovernmental Panel on Climate Change. Assessments of scientific consensus help us tap the collective wisdom of a crowd of experts. In short, people value expert consensus as a guide to help them navigate an increasingly complex and risk-filled world.

More generally, consensus is an important process in society. Human cooperation, from small groups to entire nations, requires some degree of consensus, for example on shared goals and the best means to achieve those goals. Indeed, some biologists have argued that “human societies are unable to function without consensus.” Neurological evidence even suggests that when people learn that they are in agreement with experts, reward signals are produced in the brain. Importantly, establishing consensus in one domain (e.g. climate science) can serve as a stepping stone to establishing consensus in other domains (e.g. need for climate policy).

The value of consensus is well understood by the opponents of climate action, like the fossil fuel industry. In the early 1990s, despite the fact that an international scientific consensus was already forming, the fossil fuel industry invested in misinformation campaigns to confuse the public about the level of scientific agreement that human-caused global warming is happening. As has been well-documented, fossil fuel companies learned this strategy from the tobacco industry, which invested enormous sums in marketing and public relations campaigns to sow doubt in the public mind about the causal link between smoking and lung cancer.

However, some academics have recently argued that communicators and educators should not inform the public about the strong scientific consensus on climate change. UK sociologist Warren Pearce and his colleagues recently published a commentary (and corresponding Guardian op-ed) arguing that communicating the scientific consensus is actually counter-productive. John Cook published a reply, which we summarize here.



Welcome to Skeptical Science

Posted on 25 August 2017 by John Cook





Inoculation theory: Using misinformation to fight misinformation

Posted on 17 May 2017 by John Cook

The ConversationJohn Cook, Research Assistant Professor, Center for Climate Change Communication, George Mason University.  This article was originally published on The Conversation. Read the original article.

As a psychologist researching misinformation, I focus on reducing its influence. Essentially, my goal is to put myself out of a job.

Recent developments indicate that I haven’t been doing a very good job of it. Misinformation, fake news and “alternative facts” are more prominent than ever. The Oxford Dictionary named “post-truth” as the 2016 word of the year. Science and scientific evidence have been under assault.

Fortunately, science does have a means to protect itself, and it comes from a branch of psychological research known as inoculation theory. This borrows from the logic of vaccines: A little bit of something bad helps you resist a full-blown case. In my newly published research, I’ve tried exposing people to a weak form of misinformation in order to inoculate them against the real thing – with promising results.

Two ways misinformation damages

Misinformation is being generated and disseminated at prolific rates. A recent study comparing arguments against climate science versus policy arguments against action on climate found that science denial is on the relative increase. And recent research indicates these types of effort have an impact on people’s perceptions and science literacy.

A recent study led by psychology researcher Sander van der Linden found that misinformation about climate change has a significant impact on public perceptions about climate change.

The misinformation they used in their experiment was the most shared climate article in 2016. It’s a petition, known as the Global Warming Petition Project, featuring 31,000 people with a bachelor of science or higher, who signed a statement saying humans aren’t disrupting climate. This single article lowered readers’ perception of scientific consensus. The extent that people accept there’s a scientific consensus about climate change is what researchers refer to as a “gateway belief,” influencing attitudes about climate change such as support for climate action.

At the same time that van der Linden was conducting his experiment in the U.S., I was on the other side of the planet in Australia conducting my own research into the impact of misinformation. By coincidence, I used the same myth, taking verbatim text from the Global Warming Petition Project. After showing the misinformation, I asked people to estimate the scientific consensus on human-caused global warming, in order to measure any effect.

I found similar results, with misinformation reducing people’s perception of the scientific consensus. Moreover, the misinformation affected some more than others. The more politically conservative a person was, the greater the influence of the misinformation.

Response to misinformation about climate change. Cook et al. (2017), CC BY-ND



Podcast on National Review & the science of climate science denial

Posted on 15 May 2017 by John Cook

National Review recently published an article by Oren Cass that misrepresents a 2016 paper on the scientific consensus on climate change, written by coauthors of 7 leading consensus studies and members of the Skeptical Science team (coauthors include Naomi Oreskes, Peter Doran, William Anderegg, Bart Verheggen & Stuart Carlton). I asked National Review for a right-of-reply and to their credit, they agreed. Here is my reply to Oren Cass: How to Recognize ‘Science Denial’.

National Review also published a reply-to-my-reply from Oren Cass: John Cook’s Leap of Faith. Unfortunately, Cass justifies his use of the fake expert strategy because, well, Bernie Sanders. He also misrepresents Gavin Schmidt and the IPCC, attempting to argue that I am an outlier compared to them

Interestingly, this is the same strategy that Richard Tol once tried in arguing our 97% was an outlier compared to other consensus studies, which led to my co-authoring the 2016 consensus-on-consensus study with other consensus researchers (which was the paper that Cass misrepresents, everything is coming full circle). The position of the IPCC, Gavin Schmidt and myself are in perfect agreement: our best estimate of human contribution to global warming is 100% with the lowest bound being around 50%.

Anyway, I also recorded an Evidence Squared podcast with Peter Jacobs, where we critique the original National Review article. We discuss the techniques of climate science denial, focusing on the technique of fake experts that Cass uses to cast doubt on expert agreement.



Evidence Squared #10: Debunking William Happer's carbon cycle myth

Posted on 2 May 2017 by John Cook

In the first “Breaking Debunking” mini-episode of the Evidence Squared podcast, John Cook and Peter Jacobs explain how the carbon cycle works (the CO2 we breath out originally came from the air) and debunk William Happer’s myth from CNN that breathing adds CO2 to the atmosphere.



Evidence Squared: Episode 9

Posted on 28 April 2017 by John Cook

In Episode 9 of their podcast, John Cook and Peter Jacobs talk about the March for Science, including interviews with people from the DC march.



Heartland Institute's misinformation campaign into schools

Posted on 21 April 2017 by John Cook

Last month, the Heartland Institute sent a climate denial booklet to 25,000 teachers around the US. In Episode 8 of the Evidence Squared podcast, we look at the why and how of this book. What is the chief motivation for the book’s misinformation and what are the techniques they employ to cast doubt on climate science?

Follow Evidence Squared on iTunesFacebookTwitterYouTube and Soundcloud.



New podcast Evidence Squared by John Cook & Peter Jacobs

Posted on 29 March 2017 by John Cook

Since arriving in the US two months ago, I've been developing a podcast with Peter Jacobs, a PhD student studying paleoclimate at George Mason University. While there are a number of podcasts about climate change, there were no podcasts about the science of science communication, how to talk about climate change. Today, we've launched our podcast, Evidence Squared.

You can check us out on iTunes and listen to our first four episodes (more on those in a moment). Be sure to subscribe and rate us



What do gorilla suits and blowfish fallacies have to do with climate change?

Posted on 10 February 2017 by John Cook

The ConversationThis article was originally published on The Conversation. Read the original article.

A famous psychology experiment instructed participants to watch a short video, counting the number of times players in white shirts passed the ball. If you haven’t seen it before, I encourage you to give the following short video your full attention and follow the instructions:


At the end, participants discovered the point of the video when asked if they had observed the gorilla walking through the players. Half the participants didn’t notice the gorilla at all. The lesson? When we laser-focus on specific details (like players in white shirts), we can miss the gorilla in the room.

What does this have to do with climate change? I’m a cognitive psychologist interested in better understanding and countering the techniques used to distort the science of climate change. I’ve found that understanding why some people reject climate science offers insight into how they deny science. By better understanding the techniques employed, you can counter misinformation more effectively.

Every movement that has rejected a scientific consensus, whether it be on evolution, climate change or the link between smoking and cancer, exhibits the same five characteristics of science denial (concisely summarized by the acronym FLICC). These are fake experts, logical fallacies, impossible expectations, cherry picking and conspiracy theories. When someone wants to cast doubt on a scientific finding, FLICC is an integral part of the misinformation toolbox.

The five characteristics of science denial. Skeptical Science, CC BY-ND



Skeptical Science at AGU 2016 - a recap

Posted on 26 December 2016 by BaerbelW

This year's Fall Meeting of the American Geophysical Union (AGU) has come and gone and quite a lot happened during the week from Dec. 12 to 16. As mentioned in our earlier post, several SkS teammembers were actively involved with giving talks and/or presenting posters while others were there to take it all in as was the case for me with attending AGU for the very first time.

This post is a (long) recap divided into the following sections:

SkS presentations

Denial101x featured in a poster session

Rally to stand up for Science

ERL's 10th anniversary reception

NCSE Friend of the Planet awards

Interviewing Stephan Lewandowsky

Further Reading


Some impressions from AGU 2016 (photos: Baerbel Winkler)

SkS presentations

John Cook presented a talk A Brief History of Consensus (PPT 6.8Mb), outlining the misinformation campaign against consensus, the studies quantifying the level of scientific agreement and how to neutralise misinformation.

Dana Nuccitelli presented a talk on climate model accuracy – comparing past global temperature projections to observations, and effectively debunking associated myths.  The model-data comparisons can be seen in the video below.



Skeptical Science at AGU 2016

Posted on 11 December 2016 by John Cook

Next week is going to be an exciting and busy period for Skeptical Science. Several of us will be presenting talks and posters at this week's AGU 2016 Fall Meeting.


John Cook and Dana Nuccitelli will each be presenting talks in a Monday morning session on climate literacy (session ED12A in Moscone South, room 307). This session will also feature Naomi Oreskes, Richard Alley, Mark Jacobson, Peter Sinclair, Stephan Lewandowsky and Alan Robock - not to be missed!)

John Cook will be presenting a poster about our Denial101x MOOC  in a poster session on science communication through curricula (ED13A-0923) on Monday afternoon. You can check out the poster below (full PDF 28Mb):

Sarah Green (who happens to cameo in John Cook's poster shown above, sporting a very fashionable jacket!) is also presenting a poster Monday afternoon:



Trump or NASA – who's really politicising climate science?

Posted on 25 November 2016 by John Cook

This article was originally published on The Conversation. Read the original article.The Conversation

Climate research conducted at NASA had been “heavily politicised”, said Robert Walker, a senior adviser to US President-elect Donald Trump.

This has led him to recommend stripping funding for climate research at NASA.

Walker’s claim comes with a great deal of irony. Over the past few decades, climate science has indeed become heavily politicised. But it is ideological partisans cut from the same cloth as Walker who engineered such a polarised situation.

Believe it or not, climate change used to be a bipartisan issue. In 1988, Republican George H.W. Bush pledged to “fight the greenhouse effect with the White House effect”.

Since those idealistic days when conservatives and liberals marched hand-in-hand towards a safer climate future, the level of public discourse has deteriorated.

Surveys of the US public over the past few decades show Democrats and Republicans growing further apart in their attitudes and beliefs about climate change.

For example, when asked whether most scientists agree on global warming, perceived consensus among Democrats has steadily increased over the last two decades. In contrast, perceived consensus among Republicans has been in stasis at around 50%.

Polarisation of perceived consensus among Republicans and Democrats. Dunlap et al. (2016)



Debunking climate myths with Leonardo DiCaprio's Before The Flood

Posted on 29 October 2016 by John Cook

On Sunday October 30, 9 PM EST, Leonardo DiCaprio's film Before The Flood will screen free online as well as on National Geographic. The film explores the causes and impacts of climate change, arguing for urgent action and a rapid transition off fossil fuels.

It will be streamed all week on Facebook, Youtube, Hulu, Playstation, and can be viewed on demand on Apple iTunes, Amazon, and GooglePlay. Here's more details on how to see the film and here's the trailer:

I was invited to contribute to, debunking some of the most common myths about climate change. Here are my pages on Leonardo DiCaprio's site:



Researching climate change communication at George Mason University

Posted on 7 September 2016 by John Cook

Next January, I’ll be relocating to the Center for Climate Change Communication at George Mason University. For a Brisbane boy who has never lived outside of Australia, moving to walking distance from Washington, DC is a big call. Two factors influenced this life-changing decision.

First, since I initially learnt about psychological research into debunking, my approach to climate communication has been guided by social science. When I started my research fellowship at GCI at The University of Queensland, my two-pronged approach was to research how to better communicate science, while putting that research into practice. 

As we communicated the scientific consensus on climate change, I also ran psychological experiments into the efficacy of consensus messaging. While we’ve debunked over 190 climate myths, we’ve also published the Debunking Handbook, a summary of psychological research into misinformation. Our MOOC on climate science denial is informed by a synthesis of cognitive psychology, inoculation theory and educational research.

What attracted me to MASON'S Center for Climate Change Communication (or 4C) was their approach to climate communication: a mix of theoretical research combined with practical outreach. They’re not ivory tower boffins - they directly engage with the public, putting into practice their research into the psychology of climate change.

Second, I was also enticed by the collaborative research environment at 4C - a center of scientists and students conducting academic research into the psychology of climate communication. The potential for future lines of enquiry springing from that community is quite exciting.

So after long, thoughtful conversations with my family plus focused research into how to source Vegemite in the U.S., I made the life-changing decision to relocate to the USA. Over the last five years that I’ve been at The University of Queensland, the Skeptical Science team has achieved impact far beyond our expectations, being highlighted by Senators, Presidents and Prime Ministers. My hope is that working at 4C will take our societal impact to another level.



One Nation's Malcolm Roberts is in denial about the facts of climate change

Posted on 5 August 2016 by John Cook

This article was originally published on The Conversation. Read the original article.The Conversation

The notion that climate science denial is no longer a part of Australian politics was swept away yesterday by One Nation Senator-Elect Malcolm Roberts.

In his inaugural press conference, Roberts claimed that “[t]here’s not one piece of empirical evidence anywhere, anywhere, showing that humans cause, through CO₂ production, climate change”.

He also promoted conspiracy theories that the CSIRO and Bureau of Meteorology are corrupt accomplices in climate conspiracy driven by the United Nations.

His claims conflict with many independent lines of evidence for human-caused global warming. Coincidentally, the University of Queensland is releasing a free online course this month examining the psychology and techniques of climate science denial. The very first video lecture addresses Roberts’ central claim, summarising the empirical evidence that humans are causing climate change.

Consensus of Evidence (from Denial101x course)

Scientists have observed various human fingerprints in recent climate change, documented in many peer-reviewed scientific papers.

Satellites measure less heat escaping to space at the exact wavelengths at which CO₂ absorbs energy. The upper atmosphere is cooling at the same time that the lower atmosphere is warming – a distinct pattern unique to greenhouse warming. Human activity is also changing the very structure of the atmosphere.

Human fingerprints in climate change Skeptical Science



Online course on climate science denial starts Aug 9

Posted on 2 August 2016 by John Cook

The next run of our free online course, Making Sense of Climate Science Denial, launches next Tuesday, August 9. The MOOC (Massive Open Online Course) is a collaboration between Skeptical Science and The University of Queensland, that takes a interdisciplinary look at climate science denial. We explain the psychological drivers of denial, debunk many of the most common myths about climate change and explore the scientific research into how to respond to climate misinformation.

The course first launched in April 2015. Since then, over 25,000 students from over 160 countries have enrolled in the course. A few weeks ago, we were honoured to be named one of the finalists for the first-ever edX Prize for Exceptional Contributions in Online Teaching and Learning. We've received some wonderful feedback from students who've taken the course, particularly teachers who are using our course videos in their classes. Here is a video compilation of some feedback from the students:



A brief history of fossil-fuelled climate denial

Posted on 21 June 2016 by John Cook

This article was originally published on The Conversation. Read the original article.The Conversation

The fossil fuel industry has spent many millions of dollars on confusing the public about climate change. But the role of vested interests in climate science denial is only half the picture.

Interest in this topic has spiked with the latest revelation regarding coalmining company Peabody Energy. After Peabody filed for bankruptcy earlier this year, documentation became available revealing the scope of Peabody’s funding to third parties. The list of funding recipients includes trade associations, lobby groups and climate-contrarian scientists.

This latest revelation is significant because in recent years, fossil fuel companies have become more careful to cover their tracks. An analysis by Robert Brulle found that from 2003 to 2010, organisations promoting climate misinformation received more than US$900 million of corporate funding per year.

However, Brulle found that from 2008, open funding dropped while funding through untraceable donor networks such as Donors Trust (otherwise known as the “dark money ATM”) increased. This allowed corporations to fund climate science denial while hiding their support.

The decrease in open funding of climate misinformation coincided with efforts to draw public attention to the corporate funding of climate science denial. A prominent example is Bob Ward, formerly of the UK Royal Society, who in 2006 challenged Exxon-Mobil to stop funding denialist organisations.

John Cook interviews Bob Ward at COP21, Paris.

The veils of secrecy have been temporarily lifted by the Peabody bankruptcy proceedings, revealing the extent of the company’s third-party payments, some of which went to fund climate misinformation. However, this is not the first revelation of fossil fuel funding of climate misinformation – nor is it the first case involving Peabody.

In 2015, Ben Stewart of Greenpeace posed as a consultant to fossil fuel companies and approached prominent climate denialists, offering to pay for reports promoting the benefits of fossil fuels. The denialists readily agreed to write fossil-fuel-friendly reports while hiding the funding source. One disclosed that he had been paid by Peabody to write contrarian research. He had also appeared as an expert witness and written newspaper op-eds.

John Cook interviews Ben Stewart, Greenpeace at COP21, Paris.



Ten years on: how Al Gore's An Inconvenient Truth made its mark

Posted on 30 May 2016 by John Cook

The ConversationThis article was originally published on The Conversation. Read the original article.

Ten years ago, An Inconvenient Truth opened in cinemas in the United States.

Starring former US vice president Al Gore, the documentary about the threat of climate change has undoubtedly made a mark. It won two Academy Awards, and Gore won the 2007 Nobel Peace Prize for his efforts to communicate human-induced climate change.

An Inconvenient Truth (AIT for short) is the 11th-highest-grossing documentary in the United States. According to Texan climatologist Steve Quiring:

AIT has had a much greater impact on public opinion and public awareness of global climate change than any scientific paper or report.

But has the film achieved what it set out to do – raise public awareness and change people’s behaviour in order to reduce greenhouse gas emissions?



The things people ask about the scientific consensus on climate change

Posted on 12 May 2016 by John Cook

This article was originally published on The Conversation. Read the original article.

It’s been almost a month since the paper I co-authored on the synthesis of research into the scientific consensus on climate change was published. Surveying the many studies into scientific agreement, we found that more than 90% of climate scientists agree that humans are causing global warming.

It’s a topic that has generated much interest and discussion, culminating in American Democrat Senator Sheldon Whitehouse highlighting our study on the US Senate floor this week.

My co-authors and I even participated in an Ask Me Anything (AMA) session on the online forum Reddit, answering questions about the scientific consensus.

While my own research indicates that explaining the scientific consensus isn’t that effective with those who reject climate science, it does have a positive effect for people who are open to scientific evidence.

Among this “undecided majority”, there was clearly much interest with the session generating 154,000 page views and our AMA briefly featuring on the Reddit homepage (where it was potentially viewed by 14 million people).

Here is an edited selection of some of the questions posed by Reddit readers and our answers.

Q: Why is this idea of consensus so important in climate science? Science isn’t democracy or consensus, the standard of truth is experiment.

If this were actually true, wouldn’t every experiment have to reestablish every single piece of knowledge from first principles before moving on to something new? That’s obviously not how science actually functions.

Consensus functions as a scaffolding allowing us to continue to build knowledge by addressing things that are actually unknown.

Q: Does that 97% all agree to what degree humans are causing global warming?

Different studies use different definitions. Some use the phrase “humans are causing global warming” which carries the implication that humans are a dominant contributor to global warming. Others are more explicit, specifying that humans are causing most global warming.

Within some of our own research, several definitions are used for the simple reason that different papers endorse the consensus in different ways. Some are specific about quantifying the percentage of human contribution, others just say “humans are causing climate change” without specific quantification.

We found that no matter which definition you used, you always found an overwhelming scientific consensus.



Consensus confirmed: over 90% of climate scientists believe we're causing global warming

Posted on 16 April 2016 by John Cook

This article was originally published on The Conversation. Read the original article.The Conversation

When we published a paper in 2013 finding 97% scientific consensus on human-caused global warming, what surprised me was how surprised everyone was.

Ours wasn’t the first study to find such a scientific consensus. Nor was it the second. Nor were we the last.

Nevertheless, no-one I spoke to was aware of the existing research into such a consensus. Rather, the public thought there was a 50:50 debate among scientists on the basic question of whether human activity was causing global warming.

This lack of awareness is reflected in a recent pronouncement by Senator Ted Cruz (currently competing with Donald Trump in the Republican primaries), who argued that:

The stat about the 97% of scientists is based on one discredited study.

Why is a US Senator running for President attacking University of Queensland research on scientific agreement? Cruz’s comments are the latest episode in a decades-long campaign to cast doubt on the scientific consensus on climate change.

Back in 2002, a Republican pollster advised conservatives to attack the consensus in order to win the public debate about climate policy. Conservatives complied. In conservative opinion pieces about climate change from 2007 to 2010, their number one argument was “there is no scientific consensus on climate change”.

Recent psychological research has shown that the persistent campaign to confuse the public about scientific agreement has significant societal consequences. Public perception of consensus has been shown to be a “gateway belief”, influencing a range of other climate attitudes and beliefs.

People’s awareness of the scientific consensus affects their acceptance of climate change, and their support for climate action.

The psychological importance of perceived consensus underscores why communicating the 97% consensus is important. Consensus messaging has been shown empirically to increase acceptance of climate change.

And, crucially, it’s most effective on those who are most likely to reject climate science: political conservatives.

In other words, consensus messaging has a neutralising effect, which is especially important given the highly polarised nature of the public debate about climate change.



How to inoculate people against Donald Trump's fact bending claims

Posted on 23 March 2016 by John Cook

This article was originally published on The Conversation. For Skeptical Science readers wondering what Trump has to do with climate science, note that this article is actually about critical thinking and inoculation, key topics in our Denial101x online course (Trump is just a case study).The Conversation

A potential Donald Trump presidency terrifies people worldwide. His racism, bullying, and enthusiasm for violence are a great concern for onlookers.

But we see a positive in Trump’s candidacy: We can improve our critical thinking by using him as an example of how people spread misinformation.

And there is no shortage of material to work with, given Trump’s firehose of falsehoods.

Politifact found that 78% of Trump’s statements were Mostly False, False, or “Pants on Fire” (the most extreme form of false). Fact-checking websites, parody videos, and even a debunking speech by former governor Mitt Romney have highlighted his misinformation.

But pundits and political scientists are mystified that this hasn’t hurt his level of support, with fact-checking efforts sometimes helping Trump and energising his supporters.

When facts aren’t enough

Psychologists are quite familiar with the fact that die-hard supporters of an idea aren’t swayed by contrary evidence, which can backfire and strengthen preexisting attitudes. Indeed, trying to change the minds of headstrong Trump supporters may be largely futile.

Communicating to the larger majority who are still open-minded to facts is more effective. Psychological research on science denial provides a model for how to reduce Trump’s influence on the general populace: inoculation theory.

This uses the metaphor of vaccination. Vaccines stop viruses from spreading through inoculation, which is when when healthy people are injected with a weak form of a virus and then build immunity to the virus.

The inoculation theory applies the same principle to knowledge. Research has found we can make people “immune” to misinformation using the Fact-Myth-Fallacy approach. In this method, we first explain the facts, then introduce a related myth, and then explain the technique the myth uses to distort the facts. By understanding the technique used to create the myth, people are exposed to a “weakened form” of the misinformation.

Science deniers use five techniques to distort facts: fake experts, logical fallacies, impossible expectations, cherry picking evidence, and conspiracy theories. The acronym FLICC is an easy way to remember these techniques.

FLICC: Fake experts, Logical fallacies, Impossible expectations, Cherry picking, Conspiracy theories. John Cook



The science for climate change only feeds the denial: how do you beat that?

Posted on 27 January 2016 by John Cook

The ConversationAs the scientific consensus for climate change has strengthened over the past decade, the arguments against the science of climate change have been on the increase.

That’s the surprise finding of a study, published in the journal Global Environmental Change last month, which analysed and identified the key themes in more than 16,000 publications about climate change by conservative organisations.

Conservative think-tanks are organisations that oppose policies, such as regulation of pollution by the fossil fuel industry (some have also opposed regulation of the tobacco industry in the past and, in fact, some continue to do so today).

One study found that from 1972 to 2005, over 92% of climate contrarian books originated from conservative think-tanks. They are often ground zero for misinformation casting doubt on climate science, with their messages spread by contrarian blogs, conservative media and politicians opposing climate policy.



Exxon climate revelations are just part of a long history of science misinformation

Posted on 16 November 2015 by John Cook

The ConversationA recent investigation by Pulitzer Prize winner Inside Climate News has uncovered damning activity by fossil fuel company Exxon. Long before they supplied millions of dollars to conservative think-tanks who misinformed the public about climate science, Exxon’s own scientists informed them of the scientific consensus that fossil fuel burning would cause disruptive climate change.

This echoes past activity of the tobacco industry, who knew from internal research about the health consequences of smoking but nevertheless funded misinformation casting doubt on the link between smoking and cancer. The same misinformation tactics employed by the tobacco industry are used by the fossil fuel industry.

Even the same spokespeople defending tobacco have also attacked the science on climate change. Given the obvious parallels between the activities of the tobacco and fossil fuel industries, the New York Attorney General has issued a subpoena further investigating Exxon’s activities regarding climate change.



Skeptical Science honoured by the Committee for Skeptical Inquiry

Posted on 16 October 2015 by John Cook

I’m honoured to be elected as one of ten new Fellows of the Committee for Skeptical Inquiry. It’s especially cool to be listed with some scientists whom I deeply admire such as Naomi Oreskes, Stephan Lewandowsky and James Powell.

One of the goals when I started Skeptical Science was to restore the good name of skepticism, whose reputation has been sullied by being associated with science denial. The Committee for Skeptical Inquirer have also worked hard to claim back the word skepticism, including the powerful article Deniers are not Skeptics written by a number of prominent skeptics, featuring Mark Boslough, Eugenie Scott, Richard Dawkins and Bill Nigh. They also published my article Taking Back Skepticism.

What to call those who reject mainstream climate science (to borrow the terminology of Associated Press) is a topic of hot debate. There are two key points to remember in this debate, which we emphasise in our free online course, Making Sense of Climate Science Denial.

Firstly, skepticism and denial are polar opposites. A genuine scientific skeptic first considers the full body of evidence then comes to a conclusion. A denialist comes to a conclusion first (usually influenced by ideology), then denies any science that conflicts with their position.



Conspiracy theories about Skeptical Science

Posted on 27 July 2015 by John Cook

There is a growing body of research linking climate science denial and conspiratorial thinking. While Stephan Lewandowsky's Moon Landing paper has attracted most of the attention, another important paper from Yale University has flown somewhat under the radar. This research found that when those who deny climate change are asked to name the first thing that came to mind regarding climate change, the most common type of response involved conspiracy theories.




Busting myths: a practical guide to countering science denial

Posted on 12 June 2015 by John Cook

The ConversationIt should go without saying that science should dictate how we respond to science denial. So what does scientific research tell us?

One effective way to reduce the influence of science denial is through “inoculation”: you can build resistance to misinformation by exposing people to a weak form of the misinformation.

How do we practically achieve that? There are two key elements to refuting misinformation. The first half of a debunking is offering a factual alternative. To understand what I mean by this, you need to understand what happens in a person’s mind when you correct a misconception.

People build mental models of how the world works, where all the different parts of the model fit together like cogs. Imagine one of those cogs is a myth. When you explain that the myth is false, you pluck out that cog, leaving a gap in their mental model.



Ask Me Anything about Climate Science Denial

Posted on 7 May 2015 by John Cook

The good folk at edX (who host our online course Making Sense of Climate Science Denial) generously organised a Reddit AMA (Ask Me Anything) for me this week. The AMA was scheduled to start at 7 am here in Brisbane. When I woke up at 6 am and loaded the AMA webpage on Reddit, 2000 comments had already been posted! So I gulped down a coffee and in the short time available, belted out as many answers as I could as quickly as possible (while linking to relevant videos from our MOOC). Here are a selection of my answers, grouped into categories:

Psychology of climate science denial

Q: What are the main reasons someone would deny climate change?

A: The main driver of climate science denial is political ideology. Some people don't like the solutions to climate change that involve regulation of polluting industries. Not liking the solutions, they deny there's a problem in the first place. A number of empirical studies (including my own PhD research) have found an extremely strong correlation between conservative political ideology and denial of science. And randomised experiments have demonstrated a causal relationship between the two.

This is extremely important to understand. You can't respond to science denial without understanding what's driving it. We examine this in Scott Mandia's lecture

Q: Do you think the psychology behind climate science denial can also explain other types of science denial?

A: A general principle is that people reject scientific evidence that they perceive threatens their worldview. So while different factors drive denial of different areas of science, often you will find the mechanisms are similar. For example, religious ideology drives rejection of evolution science in similar ways to political ideology driving rejection of climate science. Another thing that different types of science denial have in common is they all share the 5 characteristics of denial, as examined in this video from our course:

Q: How can you tell the difference between willful ignorance (or maybe not ignorance but disagreement) based on an agenda, and legitimate disagreement based on really misunderstanding data, or surface level policy disagreement?



Week 1 of Denial101x: 14,000 students from 159 countries

Posted on 4 May 2015 by John Cook

Last week, we launched our Massive Open Online Course (MOOC), Making Sense of Climate Science Denial. Already, there's been a great deal of interest in the course, with articles in Newsweek, Salon, Lifehacker and the formidable IFLScience. Currently, the MOOC has 14,000 enrolled students from 159 countries.

As you might imagine, the discussion forum has been vigorous and thought provoking, with a great deal of questions, suggestions and feedback. The positive feedback from the students, enjoying and learning from the week 1 material, has been overwhelming. Here's a word cloud from the student feedback.



Inoculating against science denial

Posted on 27 April 2015 by John Cook

The ConversationScience denial has real, societal consequences. Denial of the link between HIV and AIDS led to more than 330,000 premature deaths in South Africa. Denial of the link between smoking and cancer has caused millions of premature deaths. Thanks to vaccination denial, preventable diseases are making a comeback.

Denial is not something we can ignore or, well, deny. So what does scientific research say is the most effective response? Common wisdom says that communicating more science should be the solution. But a growing body of evidence indicates that this approach can actually backfire, reinforcing people’s prior beliefs.

When you present evidence that threatens a person’s worldview, it can actually strengthen their beliefs. This is called the “worldview backfire effect”. One of the first scientific experiments that observed this effect dates back to 1975.



Katharine Hayhoe's climate elevator pitch

Posted on 3 February 2015 by John Cook

At last December's AGU Fall Meeting, Peter SinclairCollin Maessen and myself spent most of the week holed up in a tiny room interviewing scientists. The downside was we missed most of the amazing, informative talks at the conference. The upside was we got to have long, in-depth conversations with some of the world's leading climate scientists.

The full interviews will be available when our MOOC, Making Sense of Climate Science Denial, comes out in April. In the meantime, Collin and Peter have been having a lot of fun releasing excerpts from our interviews (frankly, I'm a little jealous). The latest release is a wonderfully edited snippet from an interview with Katharine Hayhoe, where I ask her how she would summarise climate change in just a few floors of an elevator ride.

Stay tuned for more videos as Collin and Peter continue to dig through our goldmine of footage. We'll be announcing any new videos from our MOOC interviews on the Denial101x Facebook and Twitter pages.



Call to climate scientists: submit your quote for 97 Hours of Consensus 2015

Posted on 19 January 2015 by John Cook

On 7 September 2014, we launched 97 Hours of Consensus. Every hour for 97 consecutive hours, we published a cartoon of a climate scientist with a quote about climate change. We also published a very cool interactive webpage. Our purpose: to raise awareness of the scientific consensus on human-caused global warming.

The series was an amazing success. We reached millions of people through social and mainstream media, including President Obama tweeting about 97 hours to 43 million followers:

On 7 September 2015, we're repeating 97 Hours of Consensus with another 97 climate scientists. But with a different approach. This time, we're asking climate scientists to submit their quotes to us. So this is my call to action to the climate science community. If you're a climate scientist who:

  • has something to say about the issue of human-caused global warming,
  • and is interested in your words reaching millions of people,
  • and would like to be drawn in cartoon form

then submit your quote in our 97 Hours of Consensus Submission Form.



My AGU talk on tackling climate myths in a free online course

Posted on 20 December 2014 by John Cook

This post is based on an invited presentation I gave at the 2014 American Geophysical Union Fall Meeting in San Francisco. The talk was titled Applying Agnotology Based Learning in a MOOC to Counter Climate Misconceptions. In it, I explained the approach taken in our upcoming MOOC (Massive Open Online Course) titled Making Sense of Climate Science Denial.

The slides for my talk are available in PDF form.

For the last few years, I’ve been talking to people about agnotology-based learning.  Usually they blink or stare at me with blank eyes, responding with “agno-what now?” I explain that agnotology is the study of how and why we don’t know things, coming from the word agnostic. For example, studying the negative influence of misinformation about climate science. 

In 2009, Dan Bedford coined the term “agnotology-based learning”. I met Dan a few years ago at a previous AGU Fall Meeting. We got on famously, sharing similar attitudes to climate communication and how to address misinformation. I was especially impressed with his approach to teaching climate science by debunking myths. As well as teach the scientific concepts, this approach also equipped the students with the critical thinking skills needed to identify the misleading techniques in misinformation. 

Since then, I’ve continued to investigate agnotology-based learning, even co-authoring a paper in the Journal of Geoscience Education with Dan and Scott Mandia. When I began developing a MOOC based on the agnotology-based learning approach, naturally I was keen for Dan to be involved. This week at AGU, we recorded Dan’s MOOC lecture. Some of the SkS team think I have a bit of a bromance going with Dan but I think it’s just a strong working relationship with a healthy dose of mutual appreciation!



Our short film on the One-Two Punch of Climate Change

Posted on 1 December 2014 by John Cook

For our upcoming free online course, Making Sense of Climate Science Denial, we've been interviewing scientists in England and Australia. While on Heron Island last month talking to coral reef researchers, we also had the privilege of interviewing Sir David Attenborough about a range of issues, including the effects of climate change on the Great Barrier Reef. 

So when GetUp! announced the #ReefReels short film competition, asking for 3 minute films about the Great Barrier Reef, it seemed logical to use some of our wonderful interviews to communicate what the science is telling us about how climate change is impacting coral reefs.

The full interviews with Sir David Attenborough, Ove Hoegh-Guldberg and Annamieke Van Den Heuvel (as well as many others) will be released in March and April 2015 when we release our MOOC, Making Sense of Climate Science Denial. You can sign up for free now.



Why we need to talk about the scientific consensus on climate change

Posted on 20 November 2014 by John Cook

An interesting sequence of events followed the publication of a scientific paper the Skeptical Science team published in May last year. The paper found a 97% consensus that humans were causing global warming in relevant scientific papers. Finding an overwhelming consensus was nothing new. Studies in 2009 and 2010 also found 97% agreement among climate scientists on human-caused global warming. Nevertheless, the paper attracted much media attention, including tweets from Elon Musk and President Obama.

We expected our work would be attacked from those who reject climate science. We weren’t disappointed. Since publication, hundreds of blog posts, reports, videos, papers and op-eds have been published attacking our paper. A year and a half later, there is no sign of slowing. But this is just the latest chapter in over two decades of manufactured doubt on the scientific consensus about climate change.

What did surprise me were criticisms from scientists who accept the science on climate change. They weren’t arguing against the existence of a consensus, but whether we should be communicating the consensus. This surprised me, as our approach to climate communication was evidence-based, drawing on social science research. So in response, I along with co-author Peter Jacobs have published a scholarly paper summarising all the evidence and research underscoring the importance of consensus messaging.

One objection against consensus messaging is that scientists should be talking about evidence, rather than consensus. After all, our understanding of climate change is based on empirical measurements, not a show of hands. But this objection misunderstands the point of consensus messaging. It’s not about “proving” human-caused global warming. It’s about expressing the state of scientific understanding of climate change, which is built on a growing body of evidence.

Consensus messaging recognises the fact that people rely on expert opinion when it comes to complex scientific issues. Studies in 2011 and 2013 found that perception of scientific consensus is a gateway belief that has a flow-on effect to a number of other beliefs and attitudes. When people are aware of the high level of scientific agreement on human-caused global warming, they’re more likely to accept that climate change is happening, that humans are causing it and support policies to reduce carbon pollution.

Another argument against consensus messaging is that public understanding of the climate issue has moved on from fundamental issues such as the consensus. The evidence says otherwise. Public surveys have found that the public are deeply unaware of the consensus. On average, the public think there’s a 50:50 debate. There are several contributors to this “consensus gap”, including mainstream media’s tendency to give contrarian voices equal weight with the climate science community.

Funnily enough, a third objection to consensus messaging argues that we shouldn’t communicate consensus because public views have not moved on. In other words, the fact that public opinion about consensus hasn’t shifted over the last decade implies that consensus messaging is ineffective.

Dan Kahan argues that consensus is a polarizing message. Liberals are predisposed to respond positively to consensus messaging. Meanwhile, conservatives are more likely to reject the scientific consensus.

Political ideology certainly does influence people’s attitudes towards climate change. The following graph shows data I’ve collected from a representative sample of Americans, asking them how many climate scientists agreed about human-caused global warming. The horizontal access in this graph represents political ideology (specifically, support for an unregulated free market, free of interference from government).

These data come from research by John Cook, taken from a survey of a US representative sample (N=200).



97 Hours of Consensus reaches millions

Posted on 24 September 2014 by John Cook

On 9/7, Skeptical Science launched 97 Hours of Consensus. Every hour for 97 consecutive hours, we published a quote from a climate scientist, as well as a hand-drawn caricature of the scientist. We had a simple goal: communicate in a playful fashion the overwhelming scientific consensus that humans are causing global warming.

Now that the dust has settled, we've had a chance to analyse how the campaign went. The result exceeded our expectations. Millions of people were exposed to the 97 quotes and caricatures of climate scientists!

Tweets from our twitter account @skepticscience were retweeted by many, being seen potentially 1.1 million times. The graph below shows the number of "impressions" of our tweets, meaning the potential number of times that our followers or followers of retweeters were exposed to our tweets.



Upcoming MOOC makes sense of climate science denial

Posted on 21 September 2014 by John Cook

In collaboration with The University of Queensland, Skeptical Science is developing a MOOC, or Massive Online Open Course, that makes sense of climate science denial. The Denial101x MOOC will launch in March 2015 on the EdX platform. Registration has just opened so you can now register for free. Here is a description of the MOOC:


Denial101x: Making Sense of Climate Science Denial

Climate change is real, so why the controversy and debate? Learn to make sense of the science and to respond to climate change denial.

About this Course

In public discussions, climate change is a highly controversial topic. However, in the scientific community, there is little controversy with 97% of climate scientists concluding humans are causing global warming.

  • Why the gap between the public and scientists?
  • What are the psychological and social drivers of the rejection of the scientific consensus?
  • How has climate denial influenced public perceptions and attitudes towards climate change?

This course examines the science of climate science denial.

We will look at the most common climate myths from “global warming stopped in 1998” to “global warming is caused by the sun” to “climate impacts are nothing to worry about.”

We’ll find out what lessons are to be learnt from past climate change as well as better understand how climate models predict future climate impacts. You’ll learn both the science of climate change and the techniques used to distort the science.

With every myth we debunk, you’ll learn the critical thinking needed to identify the fallacies associated with the myth. Finally, armed with all this knowledge, you’ll learn the psychology of misinformation. This will equip you to effectively respond to climate misinformation and debunk myths.

This isn’t just a climate MOOC; it’s a MOOC about how people think about climate change.



97 hours of consensus: caricatures and quotes from 97 scientists

Posted on 7 September 2014 by John Cook

Climate scientists from across the globe feature in our 97 Hours of Consensus campaign addressing one of the most significant and harmful myths about climate change. Each hour, beginning at 9am Sunday EST, September 7th, we'll publish a statement and playful, hand-drawn caricature of a leading climate scientist. Each caricature lists the scientists’ name, title, expertise and academic institution.

97 Hours of Consensus communicates the fact that 97% of climate scientists have concluded that humans are causing global warming. The research, conducted by scientists at The University of Queensland’s Global Change Institute, University of Reading, Michigan Technological University and Memorial University of Newfoundland found that 97% of relevant climate papers endorsed human-caused global warming. The paper was published in the academic journal Environmental Research Letters in May 2013.



The power of pie-charts to communicate consensus

Posted on 10 July 2014 by John Cook

Yale University and George Mason University are conducting some of the pioneering research into the efficacy of consensus messaging. Their latest study in Climatic Change tested the effect of three different ways to communicate the scientific consensus: a simple text message, a pie-chart and metaphors (e.g., likening the 97% consensus on climate change to a 97% consensus among doctors). They found that the most effective messages in increasing awareness of consensus were the simple text message and pie-chart. The most interesting result was that pie-charts were most effective on Republicans:

Change in perceived consensus

Pie-charts get a bad rap among science communicators (and often not without reason), but in this particular instance, the pie-chart is quite effective in communicating the overwhelming agreement among climate scientists. When SJI Associates designed The Consensus Project website, they used the 97% pie-chart as the website logo. It seems they knew what they were doing (I also like the visual double-entendre of the pie-chart forming a C). They used the same imagery in the shareable infographics communicating the results of our 97% consensus paper:



An externally-valid approach to consensus messaging

Posted on 21 June 2014 by John Cook

Earlier this week, Dan Kahan published a blog post questioning the value of consensus messaging. He generously allowed me to publish a guest post, An "externally-valid" approach to consensus messaging, responding to his issues. For starters, I examine Dan's idea that the consensus gap (the gap between public perception and the 97% consensus) is due to cultural cognition. I point out that there is a consensus gap even among liberals:

A 2012 Pew surveys of the general public found that even among liberals, there is low perception of the scientific consensus on human-caused global warming. When Democrats are asked “Do scientists agree earth is getting warmer because of human activity?”, only 58% said yes. There’s a significant "consensus gap” even for those whose cultural values predispose them towards accepting the scientific consensus. A “liberal consensus gap”.

My own data, measuring climate perceptions amongst US representative samples, confirms the liberal consensus gap. The figure below shows what people said in 2013 when asked how many climate scientists agree that humans are causing global warming. The x-axis is a measure of political ideology (specifically, support for free markets). For people on the political right (e.g., more politically conservative), perception of scientific consensus decreases, just as cultural cognition predicts. However, the most relevant feature for this discussion is the perceived consensus on the left.

At the left of the political spectrum, perceived consensus is below 70%. Even those at the far left are not close to correctly perceiving the 97% consensus. Obviously cultural cognition cannot explain the liberal consensus gap.



Resources and links documenting Tol's 24 errors

Posted on 6 June 2014 by John Cook

24 Errors in Tol (2014)Yesterday, we published a list of 24 errors in Tol's critique of our consensus paper Quantifying the consensus on anthropogenic global warming in the scientific literature. The short URL for our 24 errors report, handy for tweeting and posting in comments, is:

In addition, the Global Change Institute at The University of Queensland issued a statement summarising our response to Tol (2014) including a scholarly version of the 24-errors report (e.g., the same content but without all the bright, shiny boxes).

Today, a link to our reply to Tol made it onto the homepage of Reddit Science, causing our website traffic to surge to 20 times its normal level (so apologies for the sluggish server performance earlier today).

One of the eyebrow raising elements to Tol (2014) is that his analysis still finds an overwhelming consensus on human-caused global warming. This is significant given a recent George Mason University survey found only 12% of Americans know more than 90% of climate scientists agree on human-caused global warming.

Consequently, it's worth reminding people of Tol's views on consensus, expressed in Tol (2014). I've added a freely shareable graphic to our resource of consensus graphics, featuring an excerpt from Tol (2014). Everyone is encouraged to retweet or republish the graphic which is freely available under creative commons:

Richard Tol endorses the scientific consensus on human-caused global warming



The Quantum Theory of Climate Denial

Posted on 30 April 2014 by John Cook

When you get down to the atomic level, the universe gets weird. Austrian physicist Erwin Schrödinger visualized the funkiness of the atomic world with a thought experiment, famously involving Schrödinger's cat. Maybe he thought the idea would go viral if it included a kitten.

Imagine you have some radioactive material that may or may not decay. Quantum mechanics says that if no one is observing it, the radioactive material is simultaneously in both the decaying and non-decaying states. Only when you observe the material does it collapse into one state or the other.

To illustrate how weird this is, Schrödinger imagined placing the radioactive material in a box, connected to a Geiger counter. Also in the box is a cat. If the radioactive material decays, a bottle of poison is smashed, and the cat dies. If there is no decay, then the cat lives. According to quantum theory, until the box is opened, the cat is simultaneously dead and alive. Schrödinger's cat tells us that what goes on at the microscopic level makes little sense when applied to everyday experience.



Palmer United Party needs to go back to school on carbon facts

Posted on 28 April 2014 by John Cook

When you ask Australians what proportion of climate scientists agree on the reality of human-caused global warming, the average answer is around 58%, despite evidence that the true size of the consensus is 97%.

Australians still think there is a roughly 50/50 debate among climate scientists. This is a huge “consensus gap” between public perception and reality.

A one-person embodiment of this statistic is the Palmer United Party (PUP) Tasmanian Senator-elect Jacqui Lambie. She had this to say about the scientific consensus on ABC’s Q&A:

TONY JONES: If you were to speak to a group of scientists and they were to convince you that climate change is a problem, that it’s caused by global warming and that global warming’s caused by emissions, would you think differently about it?

LAMBIE: Well of course I would, but right now I have half the scientists on this side and the other half on this side so, you know…

Crucial votes

Lambie’s views on climate change are based on a fundamental misconception about the scientific consensus on climate change. This wouldn’t matter so much, were it not for two things.

First, Lambie is one of three PUP Senators-elect who, in a bloc with Ricky Muir of the Motoring Enthusiasts Party, potentially represent four of the six votes the government needs to repeal the current carbon policy after the new Senate comes into effect in July.

Second, Lambie’s party leader Clive Palmer is beset with his own confusion about the carbon cycle, recently telling ABC’s Lateline:

If 97% (of greenhouse gas) comes from nature and 3% comes from man and we say we’ve got to reduce it by 1%, we shouldn’t just look at the 3%, the minority section coming from human enterprise; we need to look at the whole concept. If 1 or 2% comes down from nature, surely that’s a good thing and that brings us back into a balance. It’s the total carbon balance you have to look at. But we’re just focusing on this 3%.

Unpicking these misconceptions (which I will do shortly) does not mean advocating one carbon policy over another. But given PUP’s potentially decisive influence, we should at least expect the party’s elected politicians to understand the basic facts so that they might make an informed decision.



Skeptical Science consensus paper voted ERL's best article of 2013

Posted on 21 April 2014 by John Cook

Environmental Research Letters (ERL)have just announced that our paper, Quantifying the consensus on anthropogenic global warming in the scientific literature, has been voted by the ERL editorial board as the best ERL article of 2013. This award came with a prize of $500 (which we'll use to pay the journal fees of future peer-reviewed papers by the Skeptical Science team).

Certificate from Environmental Research Letters awarding Cook et al as best ERL paper of 2013.

Our consensus paper was published in Environmental Research Letters in May last year. We'd like to express our appreciation especially to the readers of Skeptical Science who generously contributed towards the payment of the page charges ($1600 in 9 hours!), making it possible for ERL to distribute the paper free of charge.

Within 24 hours of publication, our paper was tweeted by President Obama's Twitter account and received mainstream media coverage in countries all over the world. The paper has been downloaded 161,443 times, making it the most downloaded paper in over 80 Institute of Physics journals (the second most downloaded paper has 105,275 downloads). The paper continues to be cited in a wide range of scholarly journals.



Skeptical Science Widget Hacked

Posted on 1 April 2014 by Bob Lacatena

ANNOUNCEMENT — Widget Hacked

This is the widget as it appeared during the hack throughout April 1st.

Late last night, we discovered that the Skeptical Science widget website has been hacked. We are working hard to figure out what's going on.

Rest assured that all credentials and data on this site are well secured. The widget is hosted on an entirely separate server, which also — both fortunately and unfortunately — resides with a completely different host.

We do apologize to everyone who hosts and views the widget. If you are hosting the widget on your blog, there is no need to remove it. We will get it working properly soon. It's only a matter of time.


We are working with the web hosting service to resolve the issue. For now, we don't really have a handle on how the hacker got control, or why we can't fix the widget.


We have some idea now of how the hacker did it.  Doug is running some tests to confirm our theory.

The widget was designed to help to communicate to everyday people how much energy our planet has accumulated as a result of anthropogenic greenhouse gas emissions, and how quickly that energy continues to accumulate.  That rate is equivalent to a startling 4 Hiroshima atomic bombs per second.



The Myth Debunking One-Pager

Posted on 20 March 2014 by John Cook

In late 2011, I co-authored the Debunking Handbook with Stephan Lewandowsky. The purpose of the handbook was to summarise all the psychological research into misinformation and debunking into a short, concise, practical guide. We published a much more comprehensive scholarly review afterwards. Nevertheless, the much shorter version has always been the preferred option.

Until, perhaps, now. I was asked recently if I could boil down the key points of the Debunking Handbook into a one-pager. Apparently boiling down several decades of psychological research into six plain-English, graphics-heavy pages is too much in the age of Twitter :-)

As a result, here is the Debunking One-Pager:

Debunking One-Pager

An effective debunking is more about the fact than the myth

There are two major elements to an effective debunking. The most important thing when debunking a myth is identifying a compelling, memorable factual alternative to the myth. If you're debunking "the sun is causing global warming" and you're eliminating the sun as the cause, how do you communicate the alternative cause in a compelling manner? An effective debunking is more about the fact than the myth.



Peer-reviewed papers by Skeptical Science authors

Posted on 5 March 2014 by John Cook

One of the features of Skeptical Science that makes our content robust is our internal "SkS-review" system. Before any blog posts and rebuttals are published, they are critiqued and reviewed by the SkS team. This process identifies and filters out scientific inaccuracies as well as works on communicating the science more clearly and simply.

The Skeptical Science team is a diverse group of scientists and laypeople scattered all over the globe.  Their expertise covers climate science, social science, environmental science, computer science, physics, chemistry, and biochemistry.  If you want to peruse the scholarly papers published by the SkS team, check out the Google Scholar profiles of some of our team members:

The purpose of Skeptical Science is straightforward: we debunk climate misinformation with peer-reviewed science. Primarily, this involves citing the peer-reviewed research of other scientists. However, a growing aspect of SkS output is adding to the body of scientific knowledge by publishing our own peer-reviewed research. Over the last few years, Skeptical Science authors have published a number of scholarly papers in peer-reviewed journals. Two of our papers, which both have made significant impact both in the mainstream media and in the academic community, have been available to everyone by the generous donations of SkS readers.  Both papers have been marked with a badge below (click on the badges to see the posts when the papers were crowd-funded).

Climate Science

Cowtan, K., & Way, R. G. (2013). Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends. Quarterly Journal of the Royal Meteorological Society.



Cartoon: the climate contrarian guide to managing risk

Posted on 4 March 2014 by dana1981

Climate change is fundamentally a risk management problem.  Whether or not you agree with the 97 percent expert consensus on human-caused global warming, there is an undeniable risk that the consensus is correct and that we're causing dangerously rapid climate change.

Frequently, climate contrarians argue against taking action to mitigate that risk by claiming the uncertainties are too large.  One of the most visible figures to make this argument is climate scientist Judith Curry, who said in 2013,

"I can't say myself that [doing nothing] isn't the best solution."

This argument represents a failure to grasp the principles of basic risk management, as illustrated in the following cartoon.

When it comes to managing risk, uncertainty is not our friend.  Uncertainty means it's possible the outcome will be better than we expect, but it's also possible it will be much worse than we expect.  In fact, continuing with business-as-usual would only be a reasonable option in the absolute best case scenario. 



'It's been hot before': faulty logic skews the climate debate

Posted on 20 February 2014 by John Cook

This article was originally published at The Conversation.

Global warming is increasing the risk of heatwaves. This isn’t a hypothetical abstraction that our grandchildren may experience in the distant future. Heatwaves are currently getting hotter, they’re lasting longer and they’re happening more often. This is happening right now.

Of course, heatwaves have happened in the past, including before humans started altering the climate. But it’s faulty logic to suggest that this means they’re not increasing now, or that it’s not our fault.

Sadly, this logical fallacy pervades the debate over heatwaves, not to mention other extreme events such as droughts, bushfires, floods and storms and even climate change itself. What’s more, we’re hearing it with worrying regularity from our political leaders.

Heatwaves on the rise

First, the science. As the Climate Council has reported, hot days have doubled in Australia over the past half-century. During the decade from 2000 to 2009, heatwaves reached levels not expected until the 2030s. The anticipated impacts from climate change are arriving more than two decades ahead of schedule.

The increase in heatwaves in Australia is part of a larger global trend. Globally, heatwaves are happening five times more often than in the absence of human-caused global warming. This means that there is an 80% chance that any monthly heat record is due to global warming.

As the figure below indicates, the risk from heatwaves is expected to increase in the near future. Assuming our greenhouse gas emissions peak around 2040, heat records will be about 12 times more likely to occur three decades from now.

Increase in the number of heat records compared to those expected in a world without global warming. Coumou, Robinson, and Rahmstorf (2013)

The impacts of heatwaves go a lot further than tennis players’ burnt bottoms. As we are now coming to realise, heatwaves kill more Australians than any other type of extreme weather. Floods, cyclones, bushfires and lightning strikes may capture more media coverage, but heatwaves are deadlier. On top of this comes new research linking heatwaves to increased rates of suicide.

Why are heatwaves increasing? Put simply, our planet is building up heat. Over the past few decades, our climate system has been building up heat at a rate of four Hiroshima bombs every second. As we continue to emit more heat-trapping greenhouse gases into the atmosphere, the warming continues unabated.

“But it’s happened before!”

This is the point at which some people’s logic tends to go off the rails, distorting the science and insidiously distracting us from the risks. The reasoning is that as heatwaves have happened throughout Australia’s history, it follows that current heatwaves must also be entirely natural. This is a myth.

This is the classic logical fallacy of non sequitur – Latin for “it does not follow”. It’s equivalent to arguing that as humans died of cancer long before cigarettes were invented, it therefore follows that smoking does not cause cancer.

ohn Cook's Cartoon: People died of cancer before cigarettes were invented.The non sequitur logical fallacy



Dodgy Diagrams #1 - Misrepresenting IPCC Residence Time Estimates

Posted on 19 February 2014 by Dikran Marsupial

There are a number of diagrams that frequently crop up in discussions of climate change in the blogsphere that are easily demonstrated to be, at best misleading, if not actually fundamentally wrong.  A classic example is shown below, which suggests that the IPCC's estimate of residence time is at odds with those from a wide range of scientific studies.

dodgy diagram

In this case, the diagram was taken from an article at Watts Up With That, entitled "Apparently, 4 degrees spells climate doom"; Google's "search by image" shows it has also appeared on a range of other blogs.

So What is Dodgy About The Diagram?

The IPCC actually gives a residence time of about 4 years in the 2007 AR4 WG1 report (see page 948), which is completely in accordance with the other papers referenced in the diagram.  The confusion arises because there are two definitions of "lifetime" that describe different aspects of the carbon cycle.  These definitions are clearly stated on page 8 of the first (1990) WG1 IPCC report (on page 8):



Establishing consensus is vital for climate action

Posted on 7 February 2014 by Stephan Lewandowsky

This article was originally published at The Conversation.

What’s the best way to reduce the roughly half a million annual deaths from smoking in the US alone? Nearly half a million lives cut short, often with untold suffering, by a commercial product that has been known to kill its consumers for more than half a century.

We can raise the price of cigarettes through taxes, which is known to reduce demand, especially among young people who are the industry’s reservoir of future addicts to their legal product.

We can introduce plain packaging, which replaces the glamourous, glittery gold of Benson & Hedges with the graphic image of a lung destroyed by cancer. Or we can put warning labels on packs, in bus shelters, on TV. The possibilities are almost endless.

Many policy options exist, and research has shown that they work. Tobacco control policies save lives. They also save addicts the money they no longer pour into tobacco industry coffers.



Debunking climate myths: two contrasting case studies

Posted on 6 February 2014 by John Cook

This article was originally published at The Conversation. Here, I've used my original submitted headline.

Debunking myths requires an understanding of the psychological research into misinformation. But getting your refutation out in front of lots of eyeballs is a whole other matter.

Here, I look at two contrasting case studies in debunking climate myths.

If you don’t do it right, you run the risk of actually reinforcing the myth. Fortunately, there are a number of steps you can take to avoid any potential backfire effects.



Answering questions about consensus in a MOOC webinar

Posted on 25 January 2014 by John Cook

I was honoured to be invited as a guest lecturer for Climate Change in Four Dimensions, a Massive Open Online Course (MOOC) hosted at Coursera. This is a free, online course run by the University of San Diego, featuring two of my personal heroes: Richard Somerville and Naomi Oreskes. Week 2 featured some must-watch lectures by Naomi Oreskes on the nature of scientific knowledge. The required activity for that week involved reading the peer-reviewed paper authored by the Skeptical Science team, Quantifying the Consensus on Anthropogenic Global Warming in the Scientific Literature.

The webinar had students shooting questions to me about our consensus paper. The time seemed to pass all too quickly (sign of a good time) and a number of questions went unanswered. So I thought I would use this blog post to go through the webinar transcript and address the unanswered questions (the advantage of blogging is I can also bling up my answers with gratuitious infographics):

You said the authors "err[ed] on the side of least drama." Is this still a good idea?

To provide some background to this question, erring on the side of least drama (ESLD) suggests that rather than lean towards alarmism, scientists tend to be conservative and downplay their science. We discuss the evidence for this when looking at how the IPCC tend to underestimate climate impacts.

When deciding on the criteria for categorising climate papers, we took somewhat of a conservative approach in that if there was any doubt whether a paper was stating a position on anthropogenic global warming (AGW), we rated it as stating No Position on AGW. Did this significantly affect our results? Our method found that by rating abstracts, 97.1% of abstracts stating a position on AGW endorsed the consensus. When we asked scientists to rate their own papers, we found 97.2% of papers self-rated as stating a position on AGW endorsed the consensus.



Three perfect grade debunkings of climate misinformation

Posted on 21 January 2014 by John Cook

Professor Scott Mandia at Suffolk County Community College teaches his students using the approach of agnotology-based learning. Agnotology is the study of ignorance and misconceptions. Agnotology-based learning addresses misconceptions and myths while teaching climate science. Two decades of research have found that  direct refutation in the classroom is one of the most effective ways of reducing misconceptions.

As part of the college class MET103  - Global Climate Change, students pick a climate myth from the Skeptical Science list of myths. Our refutations are often written at multiple levels: Basic, Intermediate and Advanced. Students are required to carefully study all the versions of a specific myth, then summarise all the information in their own words. Students are marked on how well they describe the myth, why it persists and how well they refute the misinformation. They're encouraged to read the Debunking Handbook for techniques on effective debunking.

In 2013, three students scored 100%, well above the class average of 72% or 77% in the Spring classes. All three students used an alternative explanation to fill the gap created by the debunking. They also used simple explanations to avoid the Overkill Backfire Effect.

Countering the “It's the Sun” Argument

Robert Necci began his paper by providing an explicit warning mentioning the myth, useful in avoiding the Familiarity Backfire Effect:



Merry Christmas and Happy Holidays from Skeptical Science

Posted on 25 December 2013 by dana1981

And from Santa Claus too.

Santa Coal



Attacks on scientific consensus on climate change mirror tactics of tobacco industry

Posted on 28 November 2013 by John Cook

The importance of public perception of scientific consensus has been established in a number of studies (e.g., here, here and here). Perhaps nothing underscores its importance more than the strenuous efforts that opponents of climate action have exerted in attacking consensus. For over two decades, fossil fuel interests and right-wing ideologues have sought to cast doubt on the consensus:

Consequently, it comes as no surprise that our paper Quantifying the consensus on anthropogenic global warming in the scientific literature has come under intense attack. Since published 6 months ago, nearly 200 articles have been published online attacking our paper. The attacks have come in the form of blog posts, Youtube videos, cartoons, papers, reports and conspiracy theories. The most entertaining conspiracy theories are Christopher Monckton's suggestion that the high-impact journal Environmental Research Letters was created for the purpose of publishing our paper and Anthony Watts' accusation that Dana Nuccitelli has vested interests in oil.

Attacks on any scientific consensus, whether it be human-caused global warming or the link between smoking and cancer, exhibit five characteristics of science denial. Similarly, the attacks against our paper have exhibited the same five characteristics. Some of these characteristics are on offer in an opinion piece by Anthony Cox published in the Newcastle Herald. I was granted the opportunity to publish a response in the Newcastle Herald, which was published today:

OPINION: Climate change deniers use tobacco tactics



4 Hiroshima bombs per second: a widget to raise awareness about global warming

Posted on 25 November 2013 by John Cook

This is a working version of the widget, as it would appear on the sidebar of a blog.  To use it, just click the buttons.

Our planet is building up a lot of heat. When scientists add up all the heat warming the oceans, land, atmosphere and melting the ice, they calculate that our planet is accumulating heat at a rate of 2.5x1014 Watts. This is equivalent to 4 Hiroshima bombs worth of heat per second.

When I mention this in public talks, I see eyes as wide as saucers. Few people are aware of how much heat our climate system is absorbing. To actively communicate our planet's energy imbalance, Skeptical Science is releasing the Skeptical Science Heat Widget.

The widget can be added to just about any blog or web site. You can customise the colour of the widget, the style of the design and even the year from which the heat graph begins. It's the result of months of diligent programming and testing by SkS team member Bob Lacatena (Sphaerica). If you have a webpage or blog, here's an opportunity to help raise awareness of global warming.

If you don't have a website but are on Facebook, Bob has also put together a Facebook app and an app for the iPad and iPhone. For complete instructions on how to get and install the widget on your blog or web site, visit the Skeptical Science Widgets page.

The widget shows the amount of energy that has been and continues to be added to the earth's climate system, expressed in ways that non-scientists can more easily relate to. Meanwhile, the counter actively increases with time, showing exactly how much and how fast the planet continues to warm.

For more information on the science behind the heat in the climate system, visit the widget's companion site, This website was put together by Bob, in collaboration with the SkS team.



Skeptical Science at the 2013 AGU Fall meeting

Posted on 21 November 2013 by John Cook

The American Geophysical Union (AGU) Fall Meeting is one of the largest gatherings of climate scientists in the world. Every December, tens of thousands of Earth scientists converge on San Francisco. Over 5 days, the scientific community present a mind-boggingly huge and diverse number of talks and posters. And they offer free beer at the poster sessions!

This year, Skeptical Science team members will be presenting a number of talks and posters. Some of it will be about work we've published over the last year while we'll also be presenting upcoming research. On Monday at 10.50am, I'll be presenting the latest results from my PhD research, which includes some fascinating findings that may change the way we think about misinformation. For those not attending the conference, AGU are offering virtual options on the three talks, which means they'll all be available as live video streams. I'll post URLs of the live stream as soon as its available.

Here are the talks and posters where you'll be able to find us - do be sure to track us down at the poster sessions as there will likely be a number of SkSers hovering around (heckling the poster presenter).

Sun 8 Dec
10am - 2.30pm
Workshop John Cook Marriott Marquis Communicating climate science in an IPCC year
(registration is now full)

Mon 9 Dec
10.50am - 11.05am
Talk John Cook Moscone South, 104 The Importance of Consensus Information in Acceptance of Climate Change
Tue 10 Dec
8am - 12pm
Poster Peter Jacobs Moscone South, Halls A-C The Once and Future North Atlantic: How the Mid-Pliocene Warm Period Can Increase Stakeholder Preparedness in a Warming World
Tue 10 Dec
Talk John Cook Moscone South, 103 The Strategic Combination of Open-Access Peer-Review, Mainstream Media and Social Media to Improve Public Climate Literac
Wed 11 Dec
Talk John Cook Moscone South 104 Case Studies in Agnotology-Based Learning
Wed 11 Dec
8am - 12pm
Poster Dana Nuccitelli Moscone South, Halls A-C Taking Social Media Science Myth Debunking to a Presidential Level
Wed 11 Dec
1.40pm - 6pm
Poster Peter Jacobs Moscone South, Halls A-C It Ain’t the Heat, It’s the Humanity

Also, on Tuesday 12pm, I will also be appearing at The Commonwealth Club along with Jim Hoggan (cofounder of Desmogblog) and Bud Ward (editor, Yale Forum on Climate Change and the Media) in an interview with Greg Dalton for Climate One Radio. Here's a video of what Climate One is all about:



Broad consensus on climate change across American states

Posted on 18 November 2013 by John Cook

Reposted from The Conversation.

A recent US “survey of surveys” by Stanford University Professor Jon Krosnick has analysed public opinion on climate change in 46 of USA’s 50 states. Krosnick found to his surprise that, regardless of geography, most Americans accept that global warming is happening and that humans are causing it.

In all 46 states, they found that at least 75% of participants thought global warming was happening. Even in traditionally conservative red states such as Texas, 84% thought global warming was happening and 72% agreed humans were the cause. Acceptance of global warming increased to at least 84% for states hit by drought or vulnerable to sea level rise.

In all states, at least 65% of Americans thought humans were causing global warming. Utah showed the lowest level at 65% while acceptance was highest in New Hampshire with 90%. Most Americans also supported government curbs of greenhouse gas emissions from power plants.



Deconstructing former Australian Prime Minister John Howard's 'gut feeling' on climate change

Posted on 13 November 2013 by John Cook

This article was reposted from

Last week, former Australian Prime Minister John Howard gave a speech on climate change for the Global Warming Policy Foundation, a conservative think-tank opposed to policies that mitigate climate change. Howard characterised scientists who accept the evidence that humans are disrupting climate as religious zealots. Consequently, he is not so convinced of the scientific evidence. On what does he base his views? Howard states that “…I instinctively feel that some of the claims are exaggerated.”

Howard is guided by gut feeling rather than empirical evidence and physics. At the same time, he accuses scientists, who arrived at their position through methodical consideration of the full body of evidence, of ideological bias. How does one make sense of this? An appropriate starting place is the scientific research into the biasing influence of ideology.

There are many factors that influence our climate change knowledge and attitudes, including education, scientific literacy and personal experience. Political ideology has a significant influence on climate change beliefs. A striking demonstration of the powerful effect of ideology is the finding that as education levels increased, Democrats became more concerned about climate change while Republicans became less concerned. Ideology rather than education is the hand at the wheel driving climate attitudes.

Does this mean ideological bias is symmetrical, with liberals exaggerating the effects of climate change while conservatives downplay climate impacts? Again, we can consult empirical research for the answer.



Book review - The Hockey Stick and the Climate Wars now Available in Paperback

Posted on 6 November 2013 by John Cook

This is an updated book review of The Hockey Stick and the Climate Wars, by Michael Mann, with the paperback edition released this week. The re-release features a foreword by Bill "The Science Guy" Nye (which opens with the great line "If you like to worry about things, you are living in a great time"). The book also includes an additional chapter based on the eventful last 18 months. You can order it directly from Columbia University Press or pre-order at Amazon.

The Hockey Stick and the Climate Wars takes us into the heart of the climate change controversy via the scientist standing in the eye of the storm - Michael Mann. He provides an eye-opening account of the lengths the opponents of climate science will go to in their campaign to slander climate scientists and distract the public from the realities of human caused global warming.

Before jumping into the dogfight, the book tells us the human story of how Mann got started in science. It was surprising to learn that his PhD began with the notion that natural variability might be greater than what climate scientists thought. I also didn't realize he'd coined the term "Atlantic Multidecadal Oscillation" (AMO) off the cuff in an interview (that's the kind of trivia that a science geek like me delights in). Ironically the AMO and natural oscillations are often invoked by contrarians to cast doubt on the human influence on global warming.

Mann also describes the progress of paleoclimate science through the 1990s which puts his 1998 hockey stick research in a broader perspective. The hockey stick paper focused on all the "scientifically interesting" periods of regional climate change over the last 600 years. So a phrase that jumped out at me was Mann's characterization that the "least scientifically interesting" thing he could do with all his regional data was average it out to find the hemispheric average. It was this "least scientifically interesting" graph that sparked a smear campaign against the graph and against Michael Mann that has lasted over a decade.

As someone who has endured more attacks from the forces of climate denial than possibly any other person on the planet, Mann provides great insight into the modes of attack. He labels it the "Serengeti strategy", inspired by African lions isolating members of a zebra herd. The climate denial movement isolate individual scientists, fling reckless charges of fraud or incompetence in the attempt to discredit climate science in general - with the ultimate goal being distraction from the realities of climate change.

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?



Consensus study most downloaded paper in all Institute of Physics journals

Posted on 14 October 2013 by John Cook

In April, Skeptical Science readers became part of a landmark citizen science project when you helped crowd-fund $1,600 to make our consensus paper freely available to the public. It took just 9 hours for the crowd-funding to raise the required funds (apologies to the SkS readers who missed out on the opportunity to donate). Thanks in part to your contribution, the Consensus Project has gone on to make a significant impact. Within 24 hours, our paper was tweeted by President Obama's Twitter account and received mainstream media coverage in countries all over the world:

Figure 1: Mainstream media coverage of Cook et al. (2013).

Most downloaded paper in all Institute of Physics journals

This week, the number of downloads of our paper passed 100,000. To put this number in perspective, the previously most downloaded paper in Environmental Research Letters (ERL) has been downloaded 60,000 times. In addition to ERL, the Institute of Physics publish over 70 peer-reviewed science journals. Over the last week, Cook et al. (2013) became the most downloaded paper in all Institute of Physics journals (this paper is second).



SkS social experiment: using comment ratings to help moderation

Posted on 8 October 2013 by John Cook

Last week, the news rippled through the blogosphere that Popular Science had shut off commenting on their website. The reason: trolls and spambots had overwhelmed the comment threads. This is a great shame, partly because it should be avoidable. Surely a combination of technology, crowd-sourcing and manual moderation should be able to minimise the destructive impact of comment trolls.

To investigate this possibility, Skeptical Science is engaging in a social experiment. You, gentle readers, are the participants. The experiment is a University of Queensland research project, titled "Using comment ratings to facilitate moderation" (I've updated the SkS Privacy Policy to include information about this project). The goal is to investigate using user ratings to assist comment moderation, thus helping to maintain a high quality of discussion. This will be achieved simply through the use of two thumbs:

Thumbs Up



Public talk explaining our consensus paper & answering critics

Posted on 30 September 2013 by John Cook

I recently presented a public talk at the new Global Change Institute living building on the topic of scientific consensus. Specifically, the talk was titled Closing the consensus gap a key to increasing support for climate action. I go into why there is a scientific consensus on human-caused global warming, explain the research in our consensus paper published in Environmental Research Letters and answer 5 criticisms of our paper. Here's the full video which you can also view at the GCI website (with details of the powerpoint slides to follow):



Bulletin of the Atomic Scientists: Closing the Consensus Gap

Posted on 20 August 2013 by John Cook

The Bulletin of the Atomic Scientists is a prestigious journal, established in 1945 to warn the public about the consequences of using nuclear weapons. They've published the writings of Hans Bethe, Albert Einstein, J. Robert Oppenheimer and Mikhail Gorbachev, among others. The Bulletin is closely followed in Washington, DC, and other world capitals and uses its iconic Doomsday Clock to draw international attention to global risks and solutions. It links the work of researchers and experts with policymaking entities, with the goal of influencing public policy to protect the Earth and its inhabitants. Thus I was honoured to be invited to submit an article, Closing the consensus gap: Public support for climate policy. In this article, I discuss our paper Quantifying the Consensus and why there was a need for it - because of the two-decade long misinformation campaign against the consensus. Here's an excerpt:



Carbon Dioxide's invisibility is what causes global warming

Posted on 16 July 2013 by John Cook

Australia's leader of the opposition Tony Abbott recently derided an emission trading scheme as "so-called market in the non-delivery of an invisible substance to no one". This echoes an earlier statement where Abbott dismissed carbon dioxide as an "invisible, odourless, weightless, tasteless substance". In this modern age, most people are aware of how something that is invisible to the eye can nevertheless have a significant impact. Examples include radiation from radioactive material, germs and well, gravity. In the case of carbon dioxide, it is actually its invisibility that is the key factor in how it causes global warming.

When sunlight reaches the Earth, it passes through our atmosphere. Greenhouse gases such as carbon dioxide are invisible to sunlight, also known as shortwave radiation because of its short wavelength. This allows the sunlight to pass through the atmosphere unhindered by greenhouse gases, and warm the Earth's surface.

The warm surface of the Earth radiates infrared heat, also known as longwave radiation because of its long wavelength. Greenhouse gases absorb longwave radiation. This results in the atmosphere trapping some of the Earth's heat as it tries to escape out to space. Heat-trapping gases such as carbon dioxide make the atmosphere warmer than it would be without any greenhouse gases.

Currently, we are adding greenhouse gases to the atmosphere through the burning of fossil fuels. As more greenhouse gases accumulate in the atmosphere, more heat is being trapped. This causes global warming. Consequently, the fact that carbon dioxide lets sunlight pass freely through the atmosphere is an integral aspect of the greenhouse effect. Carbon dioxide's invisibility is a key part of what causes global warming.



The Consensus Project self-rating data now available

Posted on 8 July 2013 by John Cook

I've just uploaded the ratings provided by the scientists who rated their own climate papers, published in our peer-reviewed paper "Quantifying the consensus on anthropogenic global warming in the scientific literature". This is an opportunity to highlight one of the most important aspects of our paper. Critics of our paper have pointed to a blog post that asked 7 scientists to rate their own papers. We'd already done that, except rather than cherry pick a handful of scientists known to hold contrarian views, we blanket emailed over 8,500 scientists. This resulted in 1,200 scientists rating the level of endorsement of their own climate papers, with 2,142 papers receiving a self-rating.

While our analysis of abstracts found 97.1% consensus among abstracts stating a position on anthropogenic global warming (AGW), the method of self-rating complete papers independently found 97.2% consensus among papers self-rated as stating a position on AGW. This independent confirmation demonstrates how robust the scientific consensus is. Whether it's Naomi Oreskes' original analysis of climate research in 2004, Doran and Kendall-Zimmerman (2009) surveying the community of Earth scientists, Anderegg et al. (2010) analysing public declarations on climate change, or our own independent methods, the overwhelming consensus consistently appears.

Figure 1: Percentage of climate papers stating a position on AGW that endorse human-caused global warming. Year is the year of publication.



Climate Change Denial now available as Kindle ebook

Posted on 8 July 2013 by John Cook

Climate Change Denial by Haydn Washington and John CookSince April 2011 when Haydn Washington and I launched our book Climate Change Denial: Heads in the Sand, people have been asking me when the book will be available in ebook format. For two years, I've been answering "soon". Finally, I can answer "now"! The Kindle Edition of Climate Change Denial is now available at the Amazon store.

Our book examines the phenomenon of climate change denial. It looks at the many techniques of literal denial, where 'skeptics' deny the evidence for man-made global warming. It exposes denial within governments, who make a lot of noise about climate change but fail to back it up with action. And it examines the denial within most of us, when we let denial prosper. This book explains the climate science and the social science behind denial.

Climate change can be solved – but only when we cease to deny that it exists. This book shows how we can break through denial, accept reality, and thus solve the climate crisis. 

Our book was designed to engage scientists, university students, climate change activists as well as the general public seeking to roll back denial and act. It's been pleasing to see that over the past few years, the book has been cited extensively in the peer-reviewed literature (30 times according to Google Scholar). To recap, here are reviews of our book:



4 Hiroshima bombs worth of heat per second

Posted on 1 July 2013 by John Cook

UPDATE 27 Mar 2014: I just discovered that my talk at the Climate Action Summit was posted on YouTube:

Last weekend, I gave a talk at the Climate Action Summit on the latest climate science. During the talk, I showed the following graph of the Earth's total heat content, demonstrating that even over the last decade when surface temperature warming has slowed somewhat, the planet continues to build up heat at a rate of 4 Hiroshima bomb detonations worth of heat every second. This data comes from a paper lead authored by Australian climate scientist John Church that tallies up the heat accumulating in the oceans, warming the land and atmosphere and melting the ice:

The next day, I was (pleasantly) surprised to see an AAP journalist had written an article about my talk (and also included some of the science on extreme weather presented by the distinguished scientist Lesley Hughes who spoke after me). The headline, "Climate change like atom bomb", focused on the Hiroshima metaphor (which I believe was first used several years ago by James Hansen). The article was picked up by a number of outlets across the world with a curious concentration of coverage in India. Subsequently, a number of people have commented on this metaphor or emailed me questions. So I thought I would address in this post, with some help from Dana Nuccitelli, why we use this metaphor and how the "4 Hiroshima bombs worth of heat per second" was calculated.



Jim Powell's Inquisition of Climate Science now available in paperback

Posted on 22 June 2013 by John Cook

The Inquisition of Climate ScienceThose who reject the consensus on human-caused global warming like to compare themselves to Galileo who challenged the Church's view that the sun revolved around the Earth. It turns out this comparison has it backwards. Modern scientists follow the evidence-based scientific method that Galileo pioneered. The "consensus" of geocentrism was promoted by the church rather than the scientific community. The similarity with the current situation is that modern scientists are also being persecuted by ideologically driven groups. This persecution is documented in the book The Inquisition of Climate Science by Jim Powell, which is now available in paperback.

I initially reviewed this book when it first came out in hard cover so let me excerpt from my initial review:

Powell points out one distinction between the Roman Inquisition and the modern day Climate Inquisition.  At least the Roman inquisitors had an alternative theory - Ptolemy's 2nd Century theory of Earth-centered astronomy.  The Climate Inquisition have no alternative theory that can explain the many lines of evidence that point to human caused global warming

The persecution of Galileo is highly instructive in putting today's climate controversy in proper context. The Inquisition Of Climate Science, available in hard cover and as an e-book that can be read on Kindle, iPad and computer, is a must-read for anyone who wishes to understand the full scope of the denial industry and their modern day persecution of climate science.

Lastly, I recommend checking out this video by Powell on how we know global warming is true:



New paper on agnotology and scientific consensus

Posted on 19 June 2013 by John Cook

Agnotology is the study of ignorance and how it's produced. For example, examining how misinformation can generate misconceptions about climate change. An interesting (and influential, at least in my case) paper on this topic is Agnotology as a teaching tool: Learning climate science by studying misinformation by Daniel Bedford, a professor at Weber State University, Utah. Bedford suggests how how examining and refuting misinformation is actually a powerful way to teach climate science, sharpen critical thinking skills and raise awareness of the scientific method. He then illustrates this with case studies applied in his own college classroom. This paper opened my eyes to the educational opportunities in addressing misinformation - an approach I adopted in the chapters "Understanding Climate Change Denial" and "Rebuttals to Climate Myths" in the textbook Climate Change Science: A Modern Synthesis.

Recently, David Legates, Willie Soon and William Briggs published a paper in the journal Science & Education, Learning and Teaching Climate Science: The Perils of Consensus Knowledge Using Agnotology. The paper comments extensively on Bedford's agnotology paper. Unfortunately, it comprehensively misrepresents Bedford's arguments. Consequently, Daniel Bedford and I have co-authored a response to Legates' paper that was just published in Science & Education: Agnotology, Scientific Consensus, and the Teaching and Learning of Climate Change: A Response to Legates, Soon and Briggs. For those without library access, our paper is unfortunately behind a pay-wall. However, the full pre-press version of our paper is available here.



Live Feed of the AGU Chapman Conference on Climate Communication starting... now!

Posted on 9 June 2013 by John Cook

The American Geophysical Union (AGU) are trying something new this week. They're running a conference on climate communication where many of the talks are being broadcast live online. Online viewers are encouraged to submit questions which will be put to the talkers at the end of their talks.

I strongly recommend you check it out if you can. Today alone features an amazing array of speakers - Spencer Weart, Mike Mann, Max Boykoff, Richard Alley, Stephan Lewandowsky - and that's just the first day. Right now, Michael MacCracken is giving a fascinating talk on the early history of climate science.

Check out the list of scheduled live talks, which I've been informed will be growing as more talks are added to the live feed. On Wednesday, I'll be presenting results from my PhD research into the psychology of consensus, and I may happen to mention the Cook et al. consensus paper along the way. Hopefully this will be broadcast online as I imagine there may be a few people interested in sending in a few questions.

UPDATE (h/t to Baerbel): My session will be broadcast live on Wednesday,2:00 p.m. — 2:15 p.m. You can watch it live and also submit questions which will be put to me during the Q&A session:

The Importance of Consensus Information in Reducing the Biasing Influence of Worldview on Climate Change Attitudes

Check out the full Web Session Schedule to see all speakers and times.



Communicating climate change at the Maths of Planet Earth conference

Posted on 3 June 2013 by John Cook

2013 is the international year of Mathematics of Planet Earth. The Australian Mathematical Sciences Institute is running a conference to explore and extol the role of maths and stats in understanding the challenges of our world in a fun and accessible way. That's right, maths is fun, you heard it here! The conference will be held in Melbourne, July 8 to 12, as academics and scientists converge for a week of lectures, sessions and networking.

I was honoured to be invited to speak at the event, where I'll be talking about The challenges of communicating the reality of climate change. Here's an abstract of my talk:

Communicating the reality of climate change is a deceptively difficult proposition. The average layperson thinks of climate as the weather they experience in their daily lives. Public surveys find people more accepting of global warming on hotter days but more sceptical on cold days. However, climate change is understood through the analysis of long-term trends and regional weather patterns. Climate is in essence weather averaged over time and space. Consequently, simple questions require complex, nuanced answers. Did global warming cause a specific flood? Individual extreme weather events are difficult to blame on climate change but the probability of such events increase with global warming. Converting abstract statistics into concrete concepts that laypeople can understand and relate to is crucial to communicating the realities of climate change.

They've just posted an interview with me on their website where we discuss what I'll be talking about at the conference. The interview was conducted by Stéphanie Pradier (who incidentally is currently in her 4th year of a physics degree, something we have in common). We also delve into a number of other interesting topics such as the biasing influence of political ideology, the essential ingredient of an effective debunking and the humble beginnings of Skeptical Science. Here's the video:



The 5 characteristics of global warming consensus denial

Posted on 28 May 2013 by John Cook

All movements that reject an overwhelming scientific consensus show 5 inevitable characteristics. They celebrate fake experts, cherry pick the data, argue using misrepresentation and logical fallacies, indulge in conspiracy theories, and demand impossible expectations of what research can deliver.

These characteristics are seen in the movements that deny the scientific consensus on vaccination, HIV and AIDS and the link between smoking and cancer. They are also abundantly evident in the movement that denies the scientific consensus that humans are causing global warming.

Industry and conservative groups have been attacking scientific consensus for decades. As far back as 1991, Western Fuels Association launched a $510,000 campaign to "reposition global warming as theory (not fact)" in the public perception. A memo from communications strategist Frank Luntz leaked in 2002 advised Republican politicians to "continue to make the lack of scientific certainty a primary issue in the debate." In a recent analysis of syndicated conservative opinion pieces spanning 2007 to 2010, the most popular myth was “there is no consensus”.



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