Tag Archives: Consensus

Oreskes 2004 and Peiser

As mentioned in previous post on the consensus article in skepticalscience, there was an entry explaining the Oreskes 2004 paper. In the article, it was presented as “Oreskes 2004 and Peiser”. Which was an odd thing. Peiser didn’t write the paper together with Oreskes (otherwise it would be “Oreskes and Peiser, 2004). At the contrary, Peiser wrote a critique on the conclusion of the paper (that not a single paper rejected the consensus position). The author of this article seems to have a lot of confidence also mentioning the critique together with the Oreskes paper.

At that time, I did not know much about the Peiser critique and initially had to rely on the explanation provided by the author of the skepticalscience article. This is how the critique is presented in the article:

Oreskes 2004 and Peiser

A survey of all peer-reviewed abstracts on the subject ‘global climate change’ published between 1993 and 2003 shows that not a single paper rejected the consensus position that global warming is man caused (Oreskes 2004). 75% of the papers agreed with the consensus position while 25% made no comment either way (focused on methods or paleoclimate analysis).

Benny Peiser, a climate contrarian, repeated Oreskes’ survey and claimed to have found 34 peer reviewed studies rejecting the consensus. However, an inspection of each of the 34 studies reveals most of them don’t reject the consensus at all. The remaining articles in Peiser’s list are editorials or letters, not peer-reviewed studies. Peiser has since retracted his criticism of Oreskes survey:

“Only [a] few abstracts explicitly reject or doubt the AGW (anthropogenic global warming) consensus which is why I have publicly withdrawn this point of my critique. [snip] I do not think anyone is questioning that we are in a period of global warming. Neither do I doubt that the overwhelming majority of climatologists is agreed that the current warming period is mostly due to human impact.”

A [snip] in a skepticalscience article? I need to know more about that! What exactly got snipped in that quote from Peiser?

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GW = AGW = CAGW?

As a non-native English speaker, I often encounter new words. One such word is “equivocation” (using the same word for different things or the use of such word in multiple senses throughout an argument, leading to a false conclusion). The first time I heard about it, I recognized it as something that is frequently used in global warming/climate change communication.

At the end of last week, when searching for something related to the consensus, I landed at the Skeptical Science page titled The 97% consensus on global warming (intermediate version). I am pretty sure that I must have read this before, but having “equivocation” at the back of my mind, gave it a new dimension.

As the title suggests, its subject is the 97% consensus. It starts from the statement of the Petition Project that “there is no convincing scientific evidence that human release of carbon dioxide will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere”.

The Skeptical Science author calls this a myth and tackles it by explaining that a consensus of around 95% is found in papers like Cook et al 2013 & 2016, Oreskes 2004, Doran 2009 and Anderegg 2010. Also mentioned are the Vision Prize poll that basically found something similar and a list of scientific organizations that endorse the consensus.

I don’t know much about the Petition Project, but from the excerpt given in the Skeptical Science article, it is clear that the Petition Project statement is very specific. They claim that there is no consensus specifically on the catastrophic nature of global warming caused by human emissions.

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Define “AGW”

Spread over the Cook et al 2018 paper are the terms “anthropogenic climate change” and “anthropogenic global warming”. It is also mentioned a in table S2 of the supplementary material. I assume that “anthropogenic global warming” means that global temperatures are rising and humans have an impact. This seems to be supported by the consensus claim from the paper (my emphasis):

There is an overwhelming scientific consensus that humans are causing global warming (Cook et al 2016), with a number of studies converging on 97% agreement among publishing climate scientists or relevant climate papers (Doran and Zimmerman 2009, Anderegg et al 2010, Cook et al 2013, Carlton et al 2015).

That is a far cry from the previous statement in the Alice in Wonderland paper. In that paper, the claim was made that there is a consensus that global warming “presents a global problem”. A claim that obviously was unsupported by the papers that were referenced.

At least he skipped the “dangerous” part of the claim. It is now in line with what the referenced papers researched. As explained in the link above, the referenced papers investigated the claim that global temperatures are rising and that humans have an influence in this. Not whether it is dangerous. Not whether something should be done about it.

However, I don’t think that the term “AGW” is used in this way in the paper. This sentence in the abstract makes me think that he means something different (my emphasis):

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“Climate Risks” as conclusive as the link between Smoking and Lung cancer?

Via the Cliscep post “Don’t call me an alarmist,” says alarmist, I landed on this livescience article: Treading the Fine Line Between Climate Talk and Alarmism. It is an op-ed written by Sarah E. Myhre about climate change communication and her wish not being called an alarmist.

One thing that caught my attention in the op-ed was this statement:

We would never fault an oncologist for informing patients about the cancer risks that come with smoking. Why would we expect Earth scientists to be any different, when we’re just as certain?

It is not clear from the text what we should expect from those Earth scientists. Luckily, the links goes to an article in Scientific American, titled “Climate Risks as Conclusive as Link between Smoking and Lung Cancer”. So apparently, she means that the Earth scientists know as much from climate risks as medical scientists about the link between smoking and lung cancer…

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Sugar versus fat: why so many scientists got it so wrong for so long

Looking for more background when I was writing previous post, I came across a very lengthy, but nevertheless interesting story in The Guardian. This long read is titled The sugar conspiracy and the subject is the battle between the theory that sugar is the (main) reason for the obesity epidemic and the established theory that fat was the culprit.

This is not something recent, the controversy originated already in the middle of last century and, although the fats theory was found to be ultimately wrong, the sugar theory was ridiculed, discredited and careers were ruined. It took fifty years for the theory to resurface, leaving the question why the top nutrition scientists got is so wrong for so long.

We hear that objection often in climate change discussions: so many scientists can’t be wrong for so long. Well, it is possible and the sugar theory is only one of its manifestations.

The most interesting part of the Guardian story is the tension between the scientist who first proposed this theory (John Yudkin) and his scientific adversary (Ancel Keys). It reads like the current controversy on climate change. Replace Yudkin with your favorite skeptic, Keys with your favorite alarmist, fats with CO2, meat/dairy/sugar industry with Big Oil/Tobacco and the story sounds really modern. There are a lot of similarities between how the scientists in the two sciences treat those who are skeptical towards the consensus position.

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The lessons we learn from nutritional science

My employer is concerned about the health of his employees and subscribed us all to a health newsletter. Every two weeks we receive some health tips in about ten to fifteen lines, based on the latest findings in health science. In the last newsletter, there was one article that jumped out on me. It was titled “Lots of fats or lots of carbohydrates?”. This is how it starts: (translated from Dutch)

Nutritional Sciences made large blunders in the past. For a long time, we had to avoid fats to stay healthy. Not only was this the wrong advice, it also has proved counterproductive.

In the 1950s, scientists drew the wrong conclusions from population studies. They focused on fats as the only cause of obesity and heart disease. Recent studies provide a more nuanced picture: a diet rich in fats and low in carbohydrates works at least as well to lose weight!

This sounded very familiar. Until a few years ago, fats were seen as something bad for our health due to our sedentary life styles and considered to be THE cause of obesity with loads of negative side effects like hypertension and heart disease.

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No conspiracy theories necessary

In the US Senate Committee on Commerce, Science and Transportation the emphasis was on the consensus: there are so many scientists and organizations that agree, so why would these few deni… euh, skeptics be right and the rest of the world wrong? Last post described already two reasons why I think this is a meaningless argument anyway. The third reason is that a consensus can have it wrong and that is not that unusual. There have been many examples before where everyone agreed and in the end everyone was wrong.

There are of course the most known examples like Galileo (against the theological consensus that the Earth was the center of the Universe), Albert Einstein (against the consensus against the theory of relativity), Harlan Bretz (against the consensus geological changes were always gradual and slow), Alfred Wegerer (against the consensus that continents were unmovable), Barry Marshall and Robin Warren (against the consensus that stomach ulcers were caused by for example stress or spicy foods) and probably many others who are less known or didn’t get into the history books. They all struggled against the consensus of their time and their assertions, although correct, were rejected. There is however a consensus that very recently collapsed and even has more similarities with the global warming/climate change story.

Since the 1980s there was a consensus about the link between fat intake and coronary artery disease. Reduce one and the other will also reduce. Guidelines were issued and low-fat diets were seen as a means of combating obesity and heart disease. This gave rise to a whole industry producing low-fat products that were assumed “healthy” in the of face the guideline. This consensus was challenged by a minority group, that gradually became larger.

In the beginning of 2015 a study was published in the Annals of Internal Medicine in which researchers pooled 72 studies and clinical trials and found that total saturated fatty acid was not linked to coronary disease risk or that a lower intake of fats is beneficial for the heart.

This does of course not mean that a high fat intake would be entirely harmless, but it’s not the major culprit that the experts led us to believe until last year. There are even those who suspect that the directive to eat less fat even had harmful effects. Healthy high-fat products, such as nuts, olive oil and fish oil, were given a bad image and dietitians lost sight of the risks of a higher sugar intake (more sugars were added to low-fat products to compensate for the loss of flavor brought by the fats).

Now that is something very interesting. Here is a consensus that held from the 1980s until now, pinpointing one factor (even lacking evidence) and that the media, the public as well as the professionals bought firmly into it. Yet no conspiracy and no large-scale misinformation campaigns were needed. There was no group of people who wanted to fool anyone, nor was there any intentional deceit. This information was put out in good faith and although it was unjustified by the science, the consensus survived until last year.

There are several similarities with climate science. Both sciences study a complex, coupled system (human body and the climate system). There is however a difference in experience (thousand versus decades).

Both sciences also have their limitation in studying their subject (there are ethical objections to put people in standardized experiments versus there only be one patient and in fact it is not sure whether it is a patient or not, because of scarce reliable historical data).

This means that there is a huge uncertainty regarding the outcome of dietary studies. People are complex organisms and live in a complex interaction with their environment. There are thousands of variables and they all can influence each other. There are things like age, physical health, fitness, genetic predestination, food preferences/availability, personal habits, background and so on. dietary fat is only one of those.
The same in climate science. There are also thousands of variables and they can all influence each other. The sun, clouds, the ocean circulations, water vapor and other greenhouse gases, the biosphere, carbon cycle, and so on. CO2 is only one of those.

In such observational studies, it is not possible to pinpoint one variable as THE cause. There is no way to know whether the real cause(s) were among the tested variables.

The current medical researchers didn’t point to just another factor to replace one cause of coronary disease with another, they just showed that the consensus was not based on good scientific evidence. The dietary guideline was not put in place because the data said there was a link between dietary fats and coronary diseases, but for other considerations.

What are the chances that in 30-40 years we will be told that the current guidelines to limit CO2 emissions lacked any solid evidence and that our focus on this mirage even had harmful effects 😉

To me this example shows again that a consensus can be wrong and that is not unusual. It doesn’t mean we must dismiss every consensus, but we clearly can’t rely on it without verification. We have to keep a healthy dose of skepticism, especially in a science dealing with loads of uncertainty like dietary studies or climate studies. It is this skepticism what I think is missing in climate related issues.