Sunday, 22 June 2014

Five reasons scientists do not like the consensus on climate change

Paris 2010 - Le Penseur.jpg
There is a consensus among climate scientists that the Earth is warming, that this is mainly because of us and that it will thus continue if we do nothing. While any mainstream scientist will be able to confirm the existence of this consensus from experience, explicitly communicating this is uncomfortable to some of them. Especially in the clear way The Consensus Project does. I also feel this disease, so let me try to explain why.

1. Fuzzy definition

One reason is that the consensus is hard to define. To the above informal statement I could have added, that greenhouse gasses warm the Earth's surface, that CO2 is a greenhouse gas, that the increase in the atmospheric CO2 concentration is mainly due to human causes, and so on. That would not have changed much and also the fraction of scientists supporting this new definition would be about the same.

You could probably also add some consequences, such as sea level rise or stronger precipitation, without much changes. However, if you would start to quantify and ask about a certain range for the climate sensitivity or add some consequences that are harder to predict, such as more drought, stronger extreme precipitation, the consensus will likely become smaller, especially as more and more scientists will feel unable to answer with confidence.

Whether there is a consensus on X or not is a question about humans. Such social science questions will always be more fuzzy as questions in the natural sciences. I guess we will just have to life with that. Just because concepts are a bit fuzzy, does not mean that it does not make sense to talk about them. If you think some aspect of this fuzziness creates problems, you can do the research to show this.

2. Scientific culture

By defining a consensus and by quantifying its support, you create two groups of scientists, mainstream and fringe. This does not fit to the culture in the scientific community to keep communication channels open to all scientists and not to exclude anyone.

Naturally, also in science, as a human enterprise, you have coalitions, but we do our best to diffuse them and even in the worst case, there are normally people on speaking terms with multiple coalitions.

Also without its quantification, the consensus exists. Thus communicating it does not make that much difference. The best antidote is for scientists to do their best to keep the lines of communication open. A colleague of mine who does great work on the homogenization thinks global warming is a NATO conspiracy. My previous boss was a climate "sceptic". Both nice people and being scientists they are able to talk about their dissent in a friendlier tone as WUWT and Co.

3. Evidence

Many people, and maybe also some scientists, may confuse consensus with evidence. For a scientist referring to a consensus is not an option in his own area of expertise. Saying "everyone believes this" is not a scientific argument.

Consensus does provide some guidance and signal credibility, especially on topics where it is easily possible to test an idea. If I had a new idea and it would require an exceptionally high or low amount of future sea level rise, I would probably not worry too much as there is not much consensus yet on these predictions and I would read this literature and see if it is possible to make matters fit somehow. If my new idea would require the greenhouse effect to be wrong, I would first try to find the error in my idea, given the strong consensus, the straight forward physics and clear experimental confirmation it would be very surprising if the greenhouse theory would be wrong.

For scientists or interested people knowing there is a consensus is not enough. Fortunately, in the climate sciences the evidence is summarised every well in the IPCC reports.

The weight of the evidence clearly matters: The consensus in the nutritional sciences seems to be that you need to move more and eat less, especially eat less fat, to lose weight. As far as I can judge this is based on rather weak evidence. Finding hard evidence on nutrition is difficult, human bodies are highly complex, finding physical mechanisms is thus nearly impossible. The bodies of ice bears (eating lots of fat), lions (eating lots of protein) and gazelles (eating lots of carbs) are very similar. They all have arteries and the ice bears arteries do not get clogged by fat; they all have kidneys and the lions kidneys can process the protein and their bones do not melt away; they all have insulin, but the gazelles do not get diabetes or obesity from all those carbs. Traditional humans ate a similar range of diets without the chronic deceases we have seen the last generations. Also experiments with humans are difficult, especially when it comes to chronic decease where experiments would have to run over generations. Most findings on diet are thus based on observational studies, which can generate interesting hypotheses, but little hard evidence. It would be great if the nutritional sciences also wrote an IPCC-like report.

For a normal person, I find it completely acceptable to say, I hold this view because most of the worlds scientists agree. I did so for a long time on diet, while I now found that the standard approach does not work for me, I feel it was rational to listen to the experts as long as I did not study the topic myself. It is impossible to be an expert for every topic. In such cases the scientific consensus is a good guiding light and communicating it is valuable, especially if a large part of the population claims not to be aware of it.

4. Contrarians

The concept "consensus" is in itself uncomfortable to many scientists. Most of us are natural contrarians and our job is to make the next consensus, not to defend the old one. Even if our studies end up validating a theory, the hope and aim of a validation study is to find an interesting deviation, that may be he beginning of a new understanding.

Given this mindset and these aims, many scientists may not notice the value of consensus theories and methods. They are what we learn during our studies. When we read scientific articles we notice on which topics there is consensus and on which there is not. When you do something new, you cannot change everything at once. Ideally a new work can be woven into the network of the other consensus ideas to become the new consensus. If this is not possible yet, there will likely be a period without consensus on that topic. If there is no consensus on a certain topic, that is a clear indication that there is work to do (if the topic is important).

5. Scientific literature

A final aspect that could be troubling is that the consensus studies were published in the scientific literature. It is a good principle to keep the political climate "debate" out of science and thus out of the scientific literature as well as possible. It is hard enough to do so. Climate dissenters regularly game the system and try to get their stuff published in the scientific literature. Peer review is not perfect and some bad manuscripts can unfortunately slip through.

One could see the publication of a consensus study as a similar attempt to exploit the scientific literature. Given that all climate scientists are already aware of the consensus, such a study does not seem to be a scientific urgency. Furthermore, Dana Nuccitelli acknowledged that one of the many aims was to make "the public more aware of the consensus".

However, many social scientists do not seem to be aware of the consensus and feel justified to see blogs such as WUWT as a contribution to a scientific debate, rather than as the political blog it is, that only pretends to be about science. One of the first consensus studies was even published in the prestigious broadly read journal Science. Replications of such a study, especially if done in another or better way seem worth publishing. The large difference in the perception of the consensus on climate change between the public and climate scientists is worth studying and these consensus studies provide an important data point to estimate this difference.

Just because the result sounds like a no-brainer is no reason not to study this and confirm the idea. Not too long ago a German newspaper reported on a study whether eating breakfast was good for weight loss. A large fraction of the comments were furious that such an obvious result had been studied with public money. I must admit, that I no longer know whether the obvious result was that if you do not eat breakfast (like Italians) you eat less and thus lose weight or whether people that eat breakfast (like Germans) are less hungry and thus compensate this by eating less during the rest of the day. I think, they did find an effect, thus the obvious result was not that it naturally does not matter when you eat.

As a natural scientist, it is hard for me to judge how much these studies contribute to the social sciences. That should be the criterion. Whether an additional aim is to educate the public seems irrelevant to me. The papers were published in journals with a broad range of topics. If there were no interest from the social science, I would prefer to write up these studies in a normal report, just like an Gallop poll. However, my estimate as outsider would be that these paper are scientifically interesting for the social sciences.

Outside of science

An important political strategy to delay action on climate is to claim that the science is not settled, that there is no consensus yet. The infamous Luntz memo from 2002 to the US Republican president stated:

Voters believe that there is no consensus about global warming within the scientific community. Should the public come to believe that the scientific issues are settled, their views about global warming will change accordingly. Therefore, you need to continue to make the lack of scientific certainty a primary issue in the debate
This is important because the population places much trust in science. Thus holding that trust and the view that there is no climate change must produce considerable cognitive dissonance.

There is a consensus within the Tea Party Conservatives that human caused climate change does not exist. It is naturally inconvenient for them that this is wrong. However, I did not make up this escapist ideology. Thus for me as a scientist this is not reason to lie about the existence of a clear consensus about and strong evidence for the basics of climate change. Even if that were a bad communication strategy, which I do not believe, my role as a scientist is to speak the truth.

What do you think? Did I miss any reason why a scientist might not like the consensus concept? Or an argument why these reasons are weak if you think about it a bit longer? I will not post comments with flimsy evidence against The Consensus Project. You can do that elsewhere where people are more tolerant and already know the counter arguments by heart.

[Update, 23 Sept 2014. This post is now linked on Spiegel Online, where the local climate "skeptic" Axel Bojanowski needs no act as if I agree with him. I admit that the title suggests this, I was hoping to get a few "sceptics" to read it, but I was hoping that people reading the post itself would see that every single "reason" is countered. Thus Bojanowski was cherry picking, I hope it was not on purpose, but just by not reading carefully.

Axel Bojanowski calls the topic of the Cook et al. study a "banality". Because even the most hardened skeptics of the climate research do not doubt the physical basis that greenhouse gasses from cars, factories and power plants heat the atmosphere. (Selbst hartgesottene Kritiker der Klimaforschung zweifeln nicht an dem physikalischen Grundsatz, dass Treibhausgase aus Autos, Fabriken und Kraftwerken die Luft wärmen.) It would unfortunately be a great jump forward if Bojanowski was right.

The blog Global Warming Solved lists 16 people/blogs that agree with them that climate change is not man-made. In this list are well known people/blogs from the "skeptic" community: Roger “Tallbloke” Tattersall, The Hockey Schtick (often cited at WUWT), the German blog No Tricks Zone (Pierre Gosselin, who is followed by Bojanowski on twitter), Tom Nelson, Climate Depot (Mark Morano; CFACT), Steven Goddard, James Delingpole, Luboš Motl, and Tim Ball (regularly posts on WUWT).

Roy Spencer recently wrote a post with the "Skeptical Arguments that Don’t Hold Water". Most of which were somehow acknowledging that CO2 is a greenhouse gas, that was the biggest concession he was willing to make. He realized that even this was controversial in his community and wrote in the intro:
My obvious goal here is not to change minds that are already made up, which is impossible (by definition), but to reach 1,000+ (mostly nasty) comments in response to this post. So, help me out here!
He got "only" 700 comments, but the tendency was as expected.

At the main Australian climate skeptic blog, I once pointed out that even the host, Jo Nova, accepts that CO2 is a greenhouse gas. That produced a lively push back and no one came forward to say that naturally CO2 is a greenhouse gas.

I can only conclude that some "high profile" "sceptic" bloggers pay lip service to accepting that global warming is man-made (while many of their posts do not make sense if they would). And that at least a large part of their audiences is against accepting any scientific fact that is accepted by liberals. ]




Related reading

In case you do not like people judging abstracts, there are also surveys of the opinion of climate scientists. For example this survey by the people behind the Klimazwiebel.

Andy Skuce responds to critique of consensus study in his post: Consensus, Criticism, Communication and gives a nice overview of the various possible critiques and why they do not hold water.

On consensus and dissent in science - consensus signals credibility


Photo: „Paris 2010 - Le Penseur“ by Daniel Stockman - Flickr: Paris 2010 Day 3 - 9. Licensed with CC BY-SA 2.0 via Wikimedia Commons.

29 comments:

And Then There's Physics said...

I think those reasons make sense and I would largely agree with them - as a scientist. One point, though, is that what scientists think isn't all that relevant. The consensus project isn't about convincing scientists about the existence - or not - of a consensus. They already know. It's about illustrating the consensus to those who do not know the level of agreement in the literature. As far as I'm concerned, once someone publishes a paper, they don't really get to decide how it is used. You can't really say, "you can't assess my abstract to determine/estimate if my paper endorses a particular position or not". It's in the public domain, so is free to be used as other see fit. Of course, scientists can (and should) correct those who may misinterpret, or misunderstand, their work, but I don't believe there is any real evidence to suggest that those who performed the abstract ratings as part of the consensus project did so. As far as I'm aware, most climate scientist would agree that the result of the consensus project is self-evidently true.

Victor Venema said...

I agree, also that the opinion of a scientist is not that relevant. The consensus exists and if someone wants to communicate that, they are free to do so. Given that it is true, I see no reason why a scientist should object to that.

This post is more or less an answer to your last post where you were wondering why climate scientists that know perfectly well that there is a consensus still like to poke at the Consensus Project.

Hans Erren said...
This comment has been removed by a blog administrator.
Victor Venema said...

Hans Erren, it would be hard for a comment to be more off topic.

TLITB said...

You say:

"There is a consensus among climate scientists that the Earth is warming, that this is mainly because of us and that it will thus continue if we do nothing."

I like your proposed definition of the consensus above. I like it because this seems to me a fairly clear and unambiguous definition of a consensus to test against.

You also say (my emphasis):

"While any mainstream scientist will be able to confirm the existence of this consensus from experience, explicitly communicating this is uncomfortable to them. Especially in the clear way The Consensus Project does."

It seems clear to me that 'The Consensus Project' i.e. Cook et al 2013, does not check your definition of consensus, does it?

In fact the major bulk (nearly half) of the 97% 'consensus' shown to be found by Cook et al 2013 only matches this more ambiguous, and weaker, definition:

Implicit Endorsement: paper implies humans are causing global warming. E.g., research assumes greenhouse gases cause warming without explicitly stating humans are the cause.

Do you agree this bears no relation to your stronger, more explicit definition?

Also, could you explain why you think Cook et al 2013 explains your definition of consensus in a "clear way"?

Victor Venema said...

Dear The Leopard In The Bush, nice jump out of the bush and thanks for your nice words on my "definition", but to be honest, it is a horribly vague one. The classification in the Cook et al. paper is much more elegant.

As I already argued above, there is no right definition, but fortunately you can vary it considerably and still get about the same answer. That makes it a robust result. There have been many more consensus studies as Cook et al., each with their own definition, and they all find a similar number. This number also fits to my experience in the scientific community and holds for a large range of definitions as long as you do not include any more speculative consequences.

This is exactly the kind of comments, I had requested people would not make. However, it so beautifully illustrates a common error of argumentation by climate dissenters that I let it pass.

Could you point me to papers that claim global warming is due to greenhouse gases, but not due to humans? I am sure, that that number of papers will be very small and will not significantly change the 97% and will certainly not change it so much that you could no longer call it a consensus.

No scientific paper is perfect. It can always be improved upon, that is scientific progress. If someone asks for perfect or for proof, they have left the scientific domain. That is dogma, not science.

If you think you see a problem in a paper, the next step is not to cry wolf on WUWT, it is to try to estimate how important it is. If you find it is important you have a nice new scientific paper that contributes to our understanding (of the consensus on climate change, in this case).

I am confident your "problem" is small. The Consensus Project has been so kind to make their database available on the web, to make it easy for you to show that there is a significant problem. I wish you good luck.

John Mashey said...

It might be a useful ompare climate science on global climate change and medical science on smoking, in terms of:
1) Strength of evidence, including ability to do definitive controlled experiments.

2) Ability to make specific predictions vs statistical ones

3) Certainty/uncertainty about all detailed causal mechanisms

4) Major US Surgeon General Reports vs IPCC reports

5) Overall consensus

I'm curious of what people might think.

Victor Venema said...

I am a somewhat militant anti-smoker, as I child I ones won a huge amount of cigarettes on a wheel of fortune and destroyed them, not wanting to sell them and be responsible for the death of others.

However, I would still argue that the evidence for the kind of basic statements the consensus is about is much stronger than the evidence for smoking being bad. That is pretty much basic natural science and very solid.

However, when it comes to feedbacks and most of the consequences, you have to deal with the messiness of the world out there. There is a good reason the IPCC confidence intervals are so broad; I do not expect them to become much smaller the coming decades. The climate system and the global economy and future technological development are all every complex and it will be easy to miss something there. Thus for that part of the AGW theory, I would think that smoking is clearer, because we have more decades of data with clear changes in forcing (smoking).

For the feedbacks we fortunately have paleo data, but something could always be different this time. We have made so many other changes to the Earth and the changes will be faster than similar situation in the past. Surprises cannot be excluded and they may not be nice.

TLITB said...

@Victor Venema Sunday, 22 June 2014 15:26:00 BST

You say:

"Dear The Leopard In The Bush, nice jump out of the bush and thanks for your nice words on my "definition", but to be honest, it is a horribly vague one. The classification in the Cook et al. paper is much more elegant."

What do you mean by "The classification in the Cook et al. paper"? Could you quote it?

I don't mean to bring up any criticism against The Consensus Project here, but I certainly would like to know how you, as a scientist, understand the 'consensus' as described by it.

This is why I tried to illustrate what it meant to me as a layman; i.e. that it seems to me to largely only demonstrate agreement with this statement:

Implicit Endorsement: paper implies humans are causing global warming. E.g., research assumes greenhouse gases cause warming without explicitly stating humans are the cause.

If you think Cook et al's definition/classification/description of the consensus is elegant, yet only possible to be cognitively grasped by scientists, and not transmittable to laymen minds, then I can understand why you don't want to say any more on that subject.

Victor Venema said...

Dear TLITB, I have trouble believing that you, as an expert climate change dissenter, with so many years of experience, cannot find the open-access article by Cook et al. yourself to look up the classification. (Hint the consensus project is already linked above.)

Could you describe you cognitive challenges with understanding the class "implicit endorsement"? It seems to state that the Earth is warming and that this is caused by humans.

If you read the article, you will notice that they require that at least half of the warming in due to human influence to be rated in this category, which is more specific as my definition. It does not require that the abstract explicitly mentions greenhouse gases, but given that you did not respond to my request to mention articles on human caused global warming without increases in greenhouse gas concentrations, I guess you also realise that is not something that would invalidate the paper.

May I request that you make of copy of your next comment? This is exactly the kind of fake discussion I do not want to waste my time on, as I had already stated in the article. You can do that elsewhere. Your next comment, if not much more substantial, will thus likely not be published.

PantsOnFire said...

How does one distinguish between consensus and group think?

Harry Twinotter said...

I am happy to accept the consensus survey shows the majority of climate scientists support AGW. Some things I didn't like about the survey:

- it was a survey of scientific papers not scientists. If you were not actively publishing you were left out of the sample space.

- authors of papers were asked to evaluate their own papers. A lot did respond. But it still means the sample space was self-selecting and this might introduce bias.

TLITB said...

@Victor Venema Sunday, 22 June 2014 16:51:00 BST

You say:
"Could you describe you cognitive challenges with understanding the class "implicit endorsement"? It seems to state that the Earth is warming and that this is caused by humans.
If you read the article, you will notice that they require that at least half of the warming in due to human influence to be rated in this category, which is more specific as my definition."

I have read the Cook et al paper *and* the supplementary material. I have been diligent in only considering that material alone when trying to conclude what it could have shown.

I understand that any analysis of the Cook et al paper by dissenters or supporters after its publication has no possible bearing on what it could have elicited from the scientists at the time they were surveyed. However, more importantly, the Cook et al paper *itself* could have had no bearing on it could have elicited from the scientists at the time they were surveyed. This should be obvious since the Cook et al paper was not written until *after* they were surveyed.

So bearing this in mind I think it worth quoting from the Cook et al paper supplemetary material, the precise format and wording of the category questions that was presented to the surveyed scientists:


Endorsement: The second drop down indicates the level of endorsement for the proposition that human activity (i.e., anthropogenic greenhouse gases) is causing global warming (e.g., the increase in temperature). Note: we are not asking about your personal opinion but whether each specific paper endorses or rejects (whether explicitly or implicitly) that humans cause global warming:

1 Explicit Endorsement with Quantification: paper explicitly states that humans are causing most of global warming.
2 Explicit Endorsement without Quantification: paper explicitly states humans are causing global warming or refers to anthropogenic global warming/climate change as a given fact.
3 Implicit Endorsement: paper implies humans are causing global warming. E.g., research assumes greenhouse gases cause warming without explicitly stating humans are the cause.
4 Neutral: paper doesn't address or mention issue of what's causing global warming.
5 Implicit Rejection: paper implies humans have had a minimal impact on global warming without saying so explicitly. E.g., proposing a natural mechanism is the main cause of global warming.
6 Explicit Rejection without Quantification: paper explicitly minimizes or rejects that humans are causing global warming.
7 Explicit Rejection with Quantification: paper explicitly states that humans are causing less than half of global warming.



Note above that only in the *separate* specific wording of Endorsement category 1, is anything remotely similar to "at least half of the warming in due to human influence" offered to be considered by the surveyed scientists. i.e the words: "humans are causing most of global warming".

So this obviously leaves the scientists perfectly free, when selecting any of the other "endorse" categories 2 or 3, to not even considerthe possibility that their paper reflects an opinion that more then half of warming is due to human influence.

And as I have said above, we now know that the vast majority of scientist respondents merely chose the weaker category 3 to describe their work.

Knowing this should make it obvious that the headline 97% consensus result of Cook et al does not definitively consist of people agreeing their work matches the description that it shows "at least half of the warming in due to human influence"

Can you not see therefore, how this means the classification/definition of consensus demonstrated by Cook et al can not be as strong as the one offered by you in your article above?

EliRabett said...

There is a very simple consensus statement that 99+% of climate scientists would agree to:

Increasing CO2 in the atmosphere at current rates will increasingly cause bad things to happen. In the next one to two hundred years this will lead to VERY BAD things happening.

The rest is detail.

The problem is that amateurs and professionals cannot restrain themselves from embroidery and the denialists delight in the resulting confusion.

Every one of your points Victor, may be true, but they are irrelevant to communicating the problem

Victor Venema said...

How does one distinguish between consensus and group think?

PantsOnFire, good question, even if a very different one from the question of the above post.

Consensus can be the result of group think and it can be the result of the strength of the evidence and a scientific culture that values evidence.

A good guard against group think is that every individual scientist has an incentive to proof the current consensus wrong. It is what you become scientist for and it puts you at the fore front of your field and furthers your career. Such a scientist would meet resistance, so (s)he would have to have good arguments and should not overstate the weight of the arguments. In fields of science where it is hard to produce solid evidence, I would fear the greatest influence of group think, in the natural sciences not so much. And naturally in groups where scientific evidence is not valued the danger of group think is biggest, such as the Tea Party.

I hope to write a bit more about that later. Judith Curry is promoting an article of hers that striving for consensus is dangerous. I have trouble seeing that as more dangerous as striving for dissent without the matching arguments and evidence, but I will have a look what she writes.

- it was a survey of scientific papers not scientists. If you were not actively publishing you were left out of the sample space.
- authors of papers were asked to evaluate their own papers. A lot did respond. But it still means the sample space was self-selecting and this might introduce bias.


Why do you see it as a problem that the survey looked at abstracts and papers and not at scientists? It is a different question. A question which has also been investigated and has about the same answer. I think the people behind the Klimazwiebel did so.

Studying abstracts has many advantages. Like you already mention, it does not have problems with self-selection. The numbers are thus less likely biased. Another problem if you study scientists, you would have to define who counts as climate scientist, which is a tricky question. By studying the scientific literature you automatically weigh those scientists that focus on climate more and good scientists tend to publish more.

Finding about the same results for scientists as for the scientific literature makes the overall finding that a consensus exists more robust.

It is not that elegant that the mainstream media tend to refer to Cook et al. about the abstracts as if it is about scientists. However, given that the result is about the same, that is a minor oversight and I guess they want to avoid having to mention the term "scientific literature", which makes people turn off their telly.

Victor Venema said...

TLITB, that was your last comment on Cook et al. You have had enough space to ventilate your opinion. This is exactly the useless discussion people are having at AndThenTheresPhysics, please take it there.

If the categories 3 (and I guess also 5) are not more than 50% and less than 50%, surely it would be no problem for you to show many abstracts that wrongly got into those categories, right? You do not even have to re-rate the entire database, just make a new rating of 100 random abstracts, or of 100 category 3 abstracts, and you can show what a hoax the Cook et al. paper is.

Wouldn't that make a great WUWT post? You would be the hero of the climate change dissenters. Just do it.

Just show that Cook et al did not do what Cook et al claim they did. Show, not just suggest, because you do not like the result. If the bad statistics of Richard Tol is already worth a scientific paper, your claim would certainly be one.

John Mashey said...

Consensus (over the basic "it's warming, we're doing it, and on current path, many effects will be bad") is what you get when you attend the AGU Fall meeting (in Europe, it would be EGU). The debates aren't about that, but rather the areas of uncertainty far from the well established consensus. After all, few relevant scientists reject the Greenhouse Effect, conservation of energy and the massive consilience of data.

Group(un)think is what you get when you immerse yourself in WUWT, JoNova, etc ... as I did here. Once is enough for me.

EliRabett said...


As Eli has said, the scientific consensus is that increasing CO2 in the atmosphere at current rates will increasingly cause bad things to happen. Over the next one to two hundred years this will lead to VERY BAD things happening. We also know that the longer we wait to take action the more stressful the action will have to be. This consensus has existed for a long time, going on twenty years. Certainly since the second IPCC report in 1995.

Yet we have endure the pious tutt-tutting when someone points this out. And then wonderment when nothing is done about the problem

Victor Venema said...

Bad sounds a little unscientific. Not sure if that is part of the consensus. But it will be costly, in terms of money to rebuild the destruction and the additional burden of adaptation and in terms of human lives.

Victor Venema said...

Every one of your points Victor, may be true, but they are irrelevant to communicating the problem

That is right, in that respect this post was not for the general public. I only wanted to explain to the sometimes frustrated people why some scientists behave the way they do. And provide some arguments for these scientists why it may be okay.

David Young said...

These reasons for scientists not liking consensus statements are good ones. However, the most important reason is that consensus statements usually turn out to be wrong either completely or in part. We are dealing with this in CFD right now. The consensus about the accuracy and reliability is simply wrong and modeling experts know it and are starting to finally say it. As a lot of top people are starting to realize, this is a growing problem in science generally. The Economist last fall summarized it very well.

Climategate emails showed that this is true of climate science too, particularly in such areas as paleoclimate. Their strong language is actually pretty normal in science, but the politics of science shown there is perhaps not as common.

And Then There's Physics said...

David Young,
Firstly, even if a consensus turns out to be wrong, it doesn't mean that it didn't exist in the first place. Secondly, even if there is a recognition that the accuracy and reliability of CFD codes has been overstated, I really doubt that this implies that all previous work using CFD codes must now be thrown out and everything must be started again. I have a suspicion that this will have no real influence on our current understanding based on CFD codes. It probably simply means that the next generation of codes will be better than those used now. I would call that the natural scientific process, not some consensus destroying event. Oh, and Climategate??????

David Young said...
This comment has been removed by a blog administrator.
Victor Venema said...

David Young, you may be able to write such comments for WUWT and Co., but here your statements are seen as mainly suggestive and in need of evidence. As it was also formulated rather antagonistically and you were not friendly to my guests, I have opted to delete it.

MikeR said...

I like this post. And Rabbett's comment is very interesting. "Increasing CO2 in the atmosphere at current rates will increasingly cause bad things to happen. In the next one to two hundred years this will lead to VERY BAD things happening." He claims that 99+% of climate scientists agree with his statement. I would like to know if that is true: has anyone done such a survey? My guess is 85%.
(The closest thing to a source I know of is Bray and von Storch 2008, and raw data was only just made available for crosstabs, http://klimazwiebel.blogspot.com/2014/06/misrepresentation-of-bray-and-von.html?showComment=1403709840198#c5378143380060518114)

Rabbett, do you insist that CO2 continue increasing at current rates for one or two hundred years? Or just the results? I wasn't clear what you meant. I personally think it is very unlikely approaching impossible that CO2 will continue to go up like that; by the second half of this century I think alternative energy sources like solar power will become enough cheaper that countries will largely change over on their own.

Victor Venema said...

MikeR, my guess would be that most scientists would refuse to answer such a question: VERY BAD is a normative thing.

If the formulation would be that it is likely much cheaper to solve the problem by global collaboration as to suffer the consequences, your 85% could be a good guess.

As a citizen, my guess would be that in the worst case it will be bad for use, because like you I expect the before it becomes very bad alternative energy to become so cheap that even with free pollution rights fossil fuels will no longer be able to compete.

MikeR said...

"If the formulation would be that it is likely much cheaper to solve the problem by global collaboration as to suffer the consequences, your 85% could be a good guess." That sounds reasonable. I'm imagining, though that VERY BAD (in caps) is a whole lot bigger than a pretty expensive stressor, where we can talk about whether mitigation or adaptation is the most efficient response. I doubt that by VERY BAD Rabbett means a Permian Extinction Event or the like, but it sounds as though he's trying to bring up such a picture.
That kind of overwhelming disaster, if it were truly the consensus of climate scientists, ought to bring wholehearted cooperation from everyone of whichever politics. Say an dinosaur-killing asteroid's course were plotted as hitting Earth at the end of the century.

But if it's just a question of comparing economic expenses of mitigation and adaptation, I think that lots of us imagine that we are probably as good at it as climate scientists, and are really only interested in their estimates of climate sensitivity. I don't even see why they'd be fussed about it - why would they expect more input than that?

Jamil Dybwad said...

John Mashey, above, commented on the basis for decisions in the science of medicine vs. climate. I think that reflection is very useful. Climate scientists use huge computers to access huge phenomena that influence all living things. Variations that are really inaccessible to human everyday reasoning give consequences for many, many lives. Medicine is a chaotic science where are simple laptop can serve most computations and the errors and variation i huge. Still medicine is in everyday use and - the scientists put a lot of effort into achieving consensus on best practice. It seems some of the above commenters think that is a job for the politicians. The best of luck if you meet a doctor who shares that view of consensus in science. I think it is instructive too to look at how medical decisions are made on a population basis (vaccine, irradiation, smoking) vs how medical decisions are made in the individual case. I am not very impressed by anarchy and individualism projected on a large scale.

Victor Venema said...

I agree, striving for consensus is nothing more than trying to understand each other. If someone smart and knowledgeable disagrees with me, the best thing I can do to improve our understanding of the problem is trying to understand why we disagree, whether it is possible to reach a consensus, or whether we would need to do more research to understand a part of the problem.

However, in general I do not like comparisons with medicine that much. Humans (or any living being) are extremely complicated and have evolved intricate feedback systems. As a consequence almost anything is possible and in the end you need statistical evidence, which can only be obtained in large clinical trails. Because such clinical trails are so expensive only few are performed and typically by a few high-profile scientists. Thus in medicine I see much more possibilities for power abuse.

In climatology you just need to be smart (and sometimes a good computer and fast internet) and you can challenge any idea.

Another reason why the analogy does not hold is that you can have the wrong opinion about climate change with hardly any negative consequences. While you do have the advantage of signaling your allegiance to your coalition.

Put a climate "skeptic" on an emergency care unit and give him two treatment options: A only works if CO2 is a greenhouse gas, B only works if CO2 is not a greenhouse gas. I am sure any climate "skeptic" would chose A.

And some of them may only claim not to believe in man-made climate change, but actually like the consequences of climate change.