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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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Climate Hustle

Explaining climate change science & rebutting global warming misinformation

Scientific skepticism is healthy. Scientists should always challenge themselves to improve their understanding. Yet this isn't what happens with climate change denial. Skeptics vigorously criticise any evidence that supports man-made global warming and yet embrace any argument, op-ed, blog or study that purports to refute global warming. This website gets skeptical about global warming skepticism. Do their arguments have any scientific basis? What does the peer reviewed scientific literature say?


Scientists are figuring out the keys to convincing people about global warming

Posted on 4 May 2016 by dana1981

The latest survey data from Yale and George Mason universities underscores thepartisan divide on climate science denial – 73% of Americans realize that global warming is happening, including 71% of liberal/moderate Republicans, but the average is dragged down by the mere 47% of conservative Republicans who answer this question correctly. On the bright side, this is a big improvement from the 28% of conservative Republicans who realized global warming was happening just two years ago.

Similarly, 56% of Americans realize global warming is mostly caused by humans, including 49% of liberal/moderate Republicans, but the number is again dragged down by the 26% of conservative Republicans correctly answering this question.

yale gmu

Poll results on the cause of global warming, broken down by American political party. Illustration: Yale and George Mason universities, Politics & Global warming, Spring 2016.

The numbers and demographics expressing concern about global warming are almost identical to those accepting human-caused global warming. That particular correlation lends support to a recent paper published in Nature Climate Change, led by Jing Shi.

Can facts convince people about global warming?

Social scientist Dan Kahan has argued that ideological and cultural identity can be so strong that scientific evidence, facts, and information can’t break through it. Kahan thinks that on certain issues like climate change, ideological biases make many conservatives immune to facts. 

In fact, conservatives with higher education and general scientific knowledge are often more wrong about climate change, in what’s been coined the “smart idiot” effect. This has led Kahan to conclude that on climate change, facts and knowledge can’t sway people. However, other research has found that climate-specific knowledge does correlate with acceptance of climate science.

In the new study led by Jing Shi, the authors surveyed a total of 2,495 people in Canada, China, Germany, Switzerland, the UK, and the US. They asked questions to evaluate the participants’ specific knowledge about the physical characteristics of climate change and understanding of its causes and consequences.

Critically, they found that knowledge about the causes of climate change was correlated with higher concern about climate change in all countries, and knowledge about the consequences was linked to higher concern in most countries.

respondents from Germany and Switzerland had significantly higher scores on knowledge about physical aspects of climate change than participants from Canada and the US. Chinese respondents knew significantly more about the causes of climate change than the respondents from the other countries. German and Swiss respondents were most knowledgeable about the consequences of climate change. In contrast, participants from the US had the lowest level of knowledge about climate change among the six countries we surveyed, independent of the type of knowledge.

In short, as illustrated in the Yale/George Mason poll numbers, people who realize that humans are causing global warming are more likely to be concerned about the problem.

In Shi’s survey, the Chinese respondents had the most knowledge about the causes of global warming, with the German and Swiss participants most accurately answering the questions about its consequences. These nationalities also expressed the greatest concern about climate change. Americans showed the least climate knowledge and the least concern.

concern v knowledge

Concern about climate change (0-6 point scale) vs. average correct score on questions relevant to its causes in six countries. Illustration: Dana Nuccitelli, data from Shi et al. (2016).



Handy resources when facing a firehose of falsehoods

Posted on 3 May 2016 by BaerbelW , jg

Chances are high that you will have come across somebody somewhere on the internet who still doesn't accept the overwhelming scientific consensus on human-caused global warming. That somebody may well have used a veritable firehose of falsehoods - usually referred to as a gish-gallop - where a big list of myths is fired off in quick succession. Creating such a gish-gallop is quick & easy and the urge to try and debunk all the misinformation it contains is often quite strong, but it's also a very time-consuming task to undertake. One time-saving option to tackle it, is to just concentrate on the most egregious instances of misinformation as examples of how the writer tries to mislead his readers and to ignore the rest. But, this has the disadvantage that others might accuse you of cherry-picking what you chose to debunk.

So, what other options do you have to fairly quickly dispense with such a firehose of falsehoods?

Option #1 - The Fact-Myth-Fallacy overview

Our MOOC Denial101x debunked around 50 of the most often heard myths related to climate science using the recipe to start out with the fact, followed by a short mention of the myth (with a warning!) and finishing off with explaining the fallacy employed. A condensed version of these debunkings is available as a four-page-PDF which you can download from here:

Fact-Myth-FallacyThe fallacies are based on the five techniques used by science deniers 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



Peabody coal's contrarian scientist witnesses lose their court case

Posted on 2 May 2016 by John Abraham

In Minnesota, an administrative hearing resulted in a judicial recommendation that will have impacts across the country. It was a case argued mainly between environmental groups (such as Minnesota Center for Environmental Advocacy, and their clients Fresh Energy and the Sierra Club) and energy producers (such as the now-bankrupt coal company Peabody Energy) regarding what a reasonable social cost of carbon should be.

I was called as an expert witness in the case along with respected climate scientistDr. Andrew Dessler. We were opposed by the well-known contrarians Drs. Roy SpencerRichard Lindzen, and William Happer (who has recently received attention related to his charged fees in the case). In full disclosure, Dr. Dessler and I were not paid for our work in the case. I recently wrote about the testimony and provided links to the testimonies submitted for the case. The judge’s recommendations and how they will impact energy decisions in the USA were the keys to this trial.



2016 SkS Weekly Digest #18

Posted on 1 May 2016 by John Hartz

SkS Highlights... El Niño to La Niña... Toon of the Week... Quote of the Week... He Said What?... SkS in the News... SkS Spotlights... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 97 Hours of Consensus...

SkS Highlights

Can the Republican Party solve its science denial problem? by Dana Nuccitelli garnered the highest number of comments among the articles posted on SkS during the past week. The article was originally posted on the Climate Consensus - the 97% Guardian blog maintained by Nuccitelli and John Abraham where it generated a lengthy and quite contentious comment thread. Click here to access the Guardian article and comment thread.

El Niño to La Niñposted on SkS during the past week. a

Withering drought and sizzling temperatures from El Nino have caused food and water shortages and ravaged farming across Asia, and experts warn of a double-whammy of possible flooding from its sibling, La Nina.

The current El Nino which began last year has been one of the strongest ever, leaving the Mekong River at its lowest level in decades, causing food-related unrest in the Philippines, and smothering vast regions in a months-long heat wave often topping 40 degrees Celsius (104 Fahrenheit).

Economic losses in Southeast Asia could top $10 billion, IHS Global Insight told AFP.

The regional fever is expected to break by mid-year but fears are growing that an equally forceful La Nina will follow.

That could bring heavy rain to an already flood-prone region, exacerbating agricultural damage and leaving crops vulnerable to disease and pests.

El Nino dries up Asia as its stormy sister La Nina looms by Satish Cheney,, Apr 29, 2016

Toon of the Week

2016 Toon 18 

Hat tip to I Heart Climate Scientists



2016 SkS Weekly News Roundup #18

Posted on 30 April 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Apr 24



Tracking the 2°C Limit - March 2016

Posted on 29 April 2016 by Rob Honeycutt

The first three months of 2016 have now all been blow-out months, all rising above 1°C anomaly over the GISS mid-century baseline. This month came in at 1.28°C. In fact, all of the past 6 months have come in at an unprecedented >1°C over their baseline. In terms of our anomaly over our 1880-1909 preindustrial baseline, this clocks in at 1.528°C and we've now marked 13 months where the 12 month average has remained over 1°C. We first crossed that point in February of 2015. (Full size image.)

Reliable sources are telling me April 2016 is coming in about the same, around 1.2°C in the GISS data. The 2015/16 super El Nino is continuing to wane but we probably have a few more months of these extreme global anomalies to come before the surface station data begins to fall back to the long term mean trend line.



Can the Republican Party solve its science denial problem?

Posted on 28 April 2016 by dana1981

There’s a widespread misconception about science denial – that on issues like the safety vaccines and genetically modified foods (GMOs), denial is found predominantly on the political left, mirroring the denial of evolution and climate science on the political right. This assumption has even been presented on The Daily Show, but it’s supported by precious little evidence. In fact, as Chris Mooney documented in great detail in 2014:

[The data] do not support the idea that vaccine denial is a special left-wing cause. As for GMOs, while resistance may be strongest on the far left, worries on this issue are quite prominent across the spectrum as well.

In neither case are these beliefs a mirror image, on the left, of climate change or evolution denial [on the political right].

New polling further debunks the science denial symmetry myth

new YouGov poll provided yet more data, asking, “Do you think it is generally safe or unsafe to eat genetically modified foods?”. There was little difference in answers across political affiliations – Democrats and Republicans were evenly split on the question of safe/unsafe, and Independents were more likely to consider GMOs unsafe. Gender and family income best predicted the answers, with men and higher-income individuals more likely to consider GMOs safe.



Climate1x - Free Online Climate Science Course starts May 3rd

Posted on 27 April 2016 by Sara Harris

This is a guest post by the lecturer presenting edX's Climate1x course. Dr. Sara Harris teaches global climate change, environmental science, and oceanography in the department of Earth, Ocean, and Atmospheric Sciences at the University of British Columbia. She has a PhD in Oceanography from Oregon State University and a research background in paleoceanography and paleoclimate.

If you want to master the basics of climate science join Climate Change: The Science starting May 3rd on offered by the University of British Columbia.

More than 170 countries just signed the Paris Agreement with the goal to limit global warming to less than 2°C above pre-industrial values, and aim for less than 1.5°C. This course will help you understand what it will take for humanity to reach those goals, by learning how the climate system works.

If you’re a teacher, businessperson, journalist, student, gardener, politician, traveler, or simply an interested citizen, understanding the controls on climate and how human actions contribute to climate change can benefit you in your work and life.

The course is designed to help you be able to:

  • Explain climate basics to anyone
  • Evaluate scientific evidence about climate change and global warming
  • Describe Earth’s possible climate futures, including the role of human choices
  • Communicate about climate change issues in your region

Activities are structured for you to practice with climate science concepts, and include:

  • Short videos with embedded practice questions
  • Interactive simulations and on-line climate models to explore
  • Selected reading materials, including from SkS, such as the Debunking handbook  and the consensus on the climate consensus paper.
  • Community maps with participant-generated essays about climate change from all over the world.
  • Seeded and open discussion forums

You’ll have the opportunity to contribute content for other’s learning, by investigating climate change in your own region and posting your findings to course maps (e.g. Figure 1).  In past offerings, participants have written about bird migrations in Europe, heat waves in the Middle East, forest fires in Malaysia, sea level rise in Kiribati, and hundreds more topics.  This course will give you an excuse and the motivation to find out more about what’s going on near you, plus an opportunity to learn what’s happening in other communities around the planet.

Climate1x-MapFigure 1: Locations of contributors to the Climate Change Impacts Map during the most recent offering of Climate Change: The Science. Red pins each represent an essay written by a participant living in that location. Numbers in blue and yellow circles represent the number of essays from that region.



Climate scientists are now grading climate journalism

Posted on 26 April 2016 by Guest Author

The internet represents an extraordinary opportunity for democracy. Never before has it been possible for people from all over the world to access the latest information and collectively seek solutions to the challenges which face our planet, and not a moment too soon: the year 2015 was the hottest in human history, and the Great Barrier Reef is suffering the consequences of warming oceans right now

Yet despite the scientific consensus that global warming is real and primarily due to human activity, studies show that only about half the population in some countries with among the highest CO2 emissions per capita understand that human beings are the driving force of our changing climate. Even fewer people are aware of the scientific consensus on this question. We live in an information age, but the information isn’t getting through. How can this be?

While the internet puts information at our fingertips, it has also allowed misinformation to sow doubt and confusion in the minds of many of those whose opinions and votes will determine the future of the planet. And up to now scientists have been on the back foot in countering the spread of this misinformation and pointing the public to trustworthy sources of information on climate change. 

Climate Feedback intends to change that. It brings together a global network of scientists who use a new web-annotation platform to provide feedback on climate change reporting. Their comments, which bring context and insights from the latest research, and point out factual and logical errors where they exist, remain layered over the target article in the public domain. You can read them for yourself, right in your browser. The scientists also provide a score on a five-point scale to let you know whether the article is consistent with the science. For the first time, Climate Feedback allows you to check whether you can trust the latest breaking story on climate change.

Climate Feedback

An example of Climate Feedback in action. Scientists’ comments and ratings appear as a layer over the article. Text annotated with Hypothesis is highlighted in yellow in the web browser and scientists’ comments appear in a sidebar next to the article. Illustration: Climate Feedback



A global coalition mapping and motivating decarbonization

Posted on 25 April 2016 by Guest Author


Diplomats, business leaders, World Bank staff, and strategic partners gather just before the inaugural High-Level Assembly of the Carbon Pricing Leadership Coalition. Photograph: Joseph Robertson

Would it surprise you to learn that governments, oil companies, NGOs and major investors are coming together to map—and to motivate—the decarbonization of the global economy?

The Carbon Pricing Leadership Coalition (CPLC) is a policy-focused alliance of national and subnational governments, intergovernmental agencies, businesses and institutional investors, nonprofits and stakeholder networks. It was launched on the first day of the Paris climate negotiations, and its mission is simple: to collaborate across borders, across sectors, sharing information, know-how and capacity, to build the most economically efficient tools for decarbonization into every nation’s climate plan as soon as possible.



2016 SkS Weekly Digest #17

Posted on 24 April 2016 by John Hartz

SkS Highlights... El Niño to La Niña... Toon of the Week... Quote of the Week... She Said What?... SkS in the News... SkS Spotlights... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 97 Hours of Consensus...

SkS Highlights

World’s largest Earth science organization to continue accepting ExxonMobil sponsorship despite calls from 250+ geoscientists, a guest post by Geoffrey Supran, Ploy Achakulwisut, Ben Scandella & Britta Voss garnered the highest number of comments of the articles posted on SkS during the past week. New Video: Surveilling the Scientists by Peter Sinclair (Climate Crock of the Week) attracted the second highest number of comments. 

El Niño to La Niña

With the Pacific Ocean cooling off after a near-record El Niño, signs are pointing to an impending La Niña - the flip-side of El Niño. So, what are the odds, and if one does develop, how strong could it be?

If strong La Niña forms, here's how it will impact the U.S. by Scott Sutherland and Mario Picazo, The Weather Channel, Apr 21, 2016 

Toon of the Week

2016 Toon 17 

Hat tip to I Heart Climate Scientists



2016 SkS Weekly News Roundup #17

Posted on 23 April 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Apr 17



New Video: Surveilling the Scientists

Posted on 22 April 2016 by greenman3610

This is a re-post of Peter Sinclair's latest video



The climate change generation gap

Posted on 21 April 2016 by dana1981

Click here to read the original at the Bulletin of Atomic Scientists

Statler & Waldorf

Muppets Statler and Waldorf represent the dwindling generation of old, white, conservative, American men to which climate denial caters.  Photo courtesy of Getty Images.

A record number of Americans now view global warming as a serious threat and blame human activities as the cause. But there is apparently a generation gap out there when it comes to accepting the scientific evidence. And an ethnic gap, a gender gap, and a gap in political leaning—along with whether one can be considered one of society’s “haves” or “have nots.” So, who are these climate deniers? What is their profile?



Climate Bet for Charity, 2016 Update

Posted on 20 April 2016 by Rob Honeycutt

We are now half way into a climate bet made between a number of climate realists and climate contrarians who were commenting on the NoTricksZone blog 5 years ago. This bet originated when I made an off-handed comment at NTZ that I felt contrarians don't have the convictions of their often emphatic beliefs because I'd never found any who would bet on the climate.

Both Dana and myself were active on NTZ at that time, and we worked up a bet through Pierre Gosselin, who owns the NTZ site. Eventually we agreed to a bet stating that, based on an average of UAH and RSS satellite data, the decade of 2011 to 2020 would be warmer than the decade of 2001 to 2010. Realists saying, "Yes, this decade would be warmer." And contrarians saying, "No, this decade would not be warmer."

From there Pierre posted the bet on his website. Eventually, the climate realists raised upward of $10,000 in "realist" bets, and contrarians raised something around half of that for the "contrarian" position.

Half way through, how do things stand? That sort of depends on how you're currently tracking the data.

Running decadal average

My preferred method to track the bet is to use a running decadal average and compare where the results would be if the bet had been made ten years previous to this month. Who would win in that case? When you look at it in that context there is no point during the past 5 years when the most recent decade was cooler than the previous decade. It's been close very recently, but still the most recent decade has remained warmer than the previous in the satellite data. (Full size graphic.)



Study: humans have caused all the global warming since 1950

Posted on 19 April 2016 by dana1981

A new study published in Climate Dynamics has found that humans are responsible for virtually all of the observed global warming since the mid-20th century. It’s not a novel result – in fact, most global warming attribution studies have arrived at the same general result – but this study uses a new approach.

GW attribution studies

The percentage contribution to global warming over the past 50-65 years in two categories: human causes (left) and natural causes (right), from various peer-reviewed studies. The studies are Tett et al. 2000 (T00, dark blue), Meehl et al. 2004 (M04, red), Stone et al. 2007 (S07, green), Lean and Rind 2008 (LR08, purple), Huber and Knutti 2011 (HK11, light blue), Gillett et al. 2012 (G12, orange), Wigley and Santer 2012 (WG12, dark green), Jones et al. 2013 (J13, pink), IPCC AR5 (IPCC, light green), and Ribes et al. 2016 (R16, light purple). The numbers are best estimates from each study. Illustration: Dana Nuccitelli

Studies attempting to figure out the global warming contributions of various human and natural sources usually use a statistical approach known as ‘linear regression’. This approach assumes we know the pattern of warming that each source (forcing) will cause, but we don’t know how big the resulting warming will be. For example, we know that greenhouse gases cause more warming over land than water, the most in the Arctic, and more warming in response to rising atmospheric carbon dioxide levels.

As an example of this approach, this animated graphic shows what happens when a 2011 study by Foster & Rahmstorf removed the known natural influences from the observed global surface temperature record, leaving behind the human-caused global warming signal.



World’s largest Earth science organization to continue accepting ExxonMobil sponsorship despite calls from 250+ geoscientists

Posted on 18 April 2016 by Guest Author

Geoffrey Supran is a PhD candidate in the Department of Materials Science and Engineering at MIT.  Ploy Achakulwisut is a PhD candidate in atmospheric chemistry at Harvard University. Ben Scandella is a PhD candidate in environmental science at MIT. Britta Voss earned a PhD in Earth science from MIT and the Woods Hole Oceanographic Institution.

Last week, the President of the American Geophysical Union (AGU) - the world’s largest association of Earth scientists - announced the AGU Board’s decision to continue accepting sponsorship from ExxonMobil, despite calls for an end to this relationship from more than 250 geoscientists owing to ExxonMobil’s past and present climate science disinformation.

The AGU’s 2015 Organizational Support Policy states that “AGU will not accept funding from organizational partners that promote and/or disseminate misinformation of science, or that fund organizations that publicly promote misinformation of science,” and that Organizational Partners are bodies that “share a vested interest in and commitment to advancing and communicating science and its power to ensure a sustainable future.

MIT climate scientist Kerry Emanuel sees the AGU’s decision as “a mockery of its own bylaw,” stating that, “If the AGU cannot turn down a mere $35K from a high-profile disinformer like Exxon, then it is hard to imagine it ever adhering to its bylaw. I am considering withdrawing from the AGU.”



2016 SkS Weekly Digest #16

Posted on 17 April 2016 by John Hartz

SkS Highlights... Toon of the Week... Quote of the Week... He Said What?... SkS in the News... SkS Spotlights... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 97 Hours of Consensus...

SkS Highlights

It’s settled: 90–100% of climate experts agree on human-caused global warming by Dana Nuccitelli, (Climate Consensus - the 97%, Guardian) attracted the most comments among the articles posted on SkS during the past week. The gist of the article: 

Studies into scientific consensus on climate change

This SkS graphic summarises the studies into scientific consensus on human-caused global warming, that look at expert opinion of either climate scientists who have published peer-reviewed climate research, or peer-reviewed climate papers.

Toon of the Week

 2016 Toon 16

Hat tip to I Heart Climate Scientists



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.



2016 SkS Weekly News Roundup #16

Posted on 16 April 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Apr 10



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