Feb 25 2010

Scientific Consensus, Climate Change, and Vaccines

One of the strengths of the skeptical movement, as an intellectual community, is that we wrangle with important issues regarding the relationship between science and what people do and should accept as probably true. We deal with not only specific issues, but the bigger question of process. For example – how much weight should an individual give to any specific scientific consensus, and is this just an argument from authority?

This question has recently become central to the debate over climate change – one of those few scientific debates that fractures the skeptical community. We are fairly united when it comes to the question of ghosts, Bigfoot, and UFOs. But when certain topics come up, like climate change, there is disagreement over the meaning of consensus, what the consensus is, and the very definition of “skeptic”.

Consensus vs Authority

Deferring to the scientific consensus on a given topic is not the same thing as making an argument from authority – a logical fallacy to be avoided. The argument from authority essentially follows the pattern of concluding that a claim is true because it is being made by a person of some authority (scientific or otherwise). Most of us spend our childhood committing this logical fallacy – the right answer is whatever an adult says it is, or the teacher, or whatever the news reports “scientists” are saying.

As we mature and grow in personal knowledge we eventually cross a threshold where we feel confident relying on our own judgment, even to the point of rejecting authority. This seems to be instinctive for teenagers, and of course the rejection of authority simply because it is authority is an overcompensation. Ideally, as adults, we reach an equilibrium where we listen to authority, but understand its limits, and do not use authority as a replacement for independent thought.

As skeptics we have collectively tried to develop a nuanced and sophisticated approach to scientific authority, and many excellent articles have been written on this topic. Since we advocate rigorous and robust scientific methodology as the best way of understanding nature, we trust this process to some degree. We understand there can be fraud or sloppy studies, but generally if the research of others is all pointing toward one answer, we trust that research and its conclusions.

But science is complex, and few people can master more than a fairly narrow range of scientific expertise. And so outside our area of expertise (which is all of science for non-scientists) the best approach to take, in my opinion, is a hybrid approach – first, try to understand what is the consensus of scientific opinion. This is a good starting point – what do scientists believe, what do they agree on, and where is there legitimate controversy? How sure are they of their conclusions, and how strong is the consensus on any particular question?

But also, those interested in science will want to understand the evidence directly and how it relates to the consensus. But at the same time it must be recognized that a non-expert understanding of the evidence is a mere shadow of expert understanding. For example, I have read many articles about Archaeopteryx – a transitional species between theropod dinosaurs and modern birds. I can rattle off some of the anatomical details that mark Archaeopteryx as transitional – the presence of teeth and a long bony tail, for example. But there are details of anatomy that I cannot hope to appreciate, that require months or years of study and apprenticeship, and experience actually examining and describing fossils, of immersing oneself in the literature at the finest level of technical detail. And so ultimately I am trusting experts to interpret the fossil for me – not to mention to reconstruct the bones in the first place. I can only try to understand it on the deepest level I can.

What I conclude from this is that it is extreme hubris to substitute one’s frail non-expert assessment of a detailed scientific discipline for the consensus of opinion of scientific experts.

But there is still more complexity to this issue. First, the consensus of opinion is not always right – it is just usually right. So one can always think that for any particular question this is one of those rare times when the consensus got it wrong. Also, there is almost always a minority opinion among experts – the outlier who is an expert but who constructs the evidence in a different way. So the non-expert can always tell themselves that a particular scientist who is an expert agrees with their opinion. This is not very reassuring, because such minority opinions are in the minority for a reason, and generally turn out to be false. (Although they serve a very useful function in the process of debate and analysis that is science.)

Further, I would argue that there are skill sets that apply, at least to some degree, to just about any science. There is knowledge of scientific methodology and the pitfalls of pathological science. So it is possible to recognize pathological science even in a discipline in which one is not an expert. But even still such out-of-field critiques should be undertaken with extreme caution. The question is – is the criticism dependent upon a detailed technical knowledge of the field, or a recognition that some underlying assumptions and methods are wrong. Even in the latter case, it is good practice to check oneself with an actual expert, to make sure you are not missing something.

I offer as an example the recent criticism of evolutionary theory by non-biologists Fodor and Piattelli-Palmarini. P.Z. Myers explains very well where they went wrong – they make all the mistakes of not respecting a consensus or the limits of their technical knowledge outside their area of expertise.

Climate Change

Getting back to climate change, all of the complexities of assessing consensus are in play. Generally, non-experts tend to accept or reject anthropogenic climate change based upon their politics and world-view. That is a strong indication that most people are not assessing the science objectively, but are simply fitting the science to their ideology.

Don Braman, a faculty member of George Washington University and part of The Cultural Cognition Project, is quoted as saying:

“People tend to conform their factual beliefs to ones that are consistent with their cultural outlook, their world view,” Braman says.

The Cultural Cognition Project has conducted several experiments to back that up.

In the same report, Robert Kennedy Jr. is quoted as saying:

“Ninety-eight percent of the research climatologists in the world say that global warming is real, that its impacts are going to be catastrophic,” he argued. “There are 2 percent who disagree with that. I have a choice of believing the 98 percent or the 2 percent.”

That is a basic statement of acceptance of the scientific consensus. But Robert Kennedy is not always a fan of the scientific consensus – for example he rejects the scientific consensus on vaccines, choosing to believe that the consensus is a deliberate fraud (exactly what global warming dissidents say about the climate change consensus). This makes Robert Kennedy a hypocrite – he accepts the scientific consensus and cites its authority when it suits his politics, and then blithely rejects it  (spinning absurd conspiracy theories that would make Jesse Ventura blush) when it is inconvenient to his politics.

But Kennedy is not alone – this seems to be what most people do most of the time. In fact I would argue that we need to be especially suspicious of our scientific opinions on controversial topics when they conform to our personal ideology (whether political, social, or religious). That is when we need to step back and ask hard questions that challenge the views we want to hold. We also need to make sure that our process is consistent across questions – are we citing the scientific consensus on one issue and rejecting it on another? Are we citing conflicts of interest for researchers whose conclusions we don’t like, and ignoring them for researchers whose conclusions confirm our beliefs?


Being a skeptic is partly about wringing our hands and closely examining these very questions – especially as they pertain to our own beliefs. The question of scientific consensus is complicated, and my views on the topic have evolved over the years as I have discussed the issue with my fellow skeptics and tried to apply it to specific issues. It is an issue worth examining closely.

50 responses so far

50 thoughts on “Scientific Consensus, Climate Change, and Vaccines”

  1. crtopher says:

    This is a nice post Steve and a topic I think about a lot. Some of my religious friends like to say I have a faith in science just as they have a faith in religion or God. There are many rebuttals to this of course but at the end of the day I just say that I believe in the scientific process as a way to gain knowledge and understand the natural world. I often have to describe the scientific process because many many people don’t actually know what it’s about. I say to people that I believe this is the best way we humans have of gaining knowledge, but there are certainly many things that science is yet to elucidate, and certainly many things science may never answer.

    The best thing about science is that we are happy to say “don’t know, needs more work” where as non-scientific type of thinking will see people making things up just to fill in the gaps of our knowledge, as if made up stuff is better than having a hole there. I think this is ultimately what religion and theology do for people – fill in those holes that people are anxious about having filled.

    Anyway, climate science has been a real challenge for me because its an area i knew nothing about, and yet i found people all around me had very strong opinions one way or the other and expected me to also have a strong opinion. Many of those strongly opinionated people were of course ideologically driven. So I did my best to do some reading (not things printed in the general media) and understand the history of climate science.

    I agree with you that as skeptics we need to do our best to inform ourselves as much as our time, resources and intellect allow. But at some point one has to accept that “I am not an expert here”. It is extreme hubris as you point out to think that a few months reading can make me as authoritative as someone who has devoted many years of their life researching and writing about climate change. So in the end I had to say well I defer to the expert consensus here, as much as from a personal point of view I DON’T WANT TO BELIEVE IN CLIMATE CHANGE! I had to recognise that ideology i had, and resist it.

    Anyway, sorry to blather. I liked your post. Cheers.

  2. CW says:

    Ditto on everything crtopher said – goes for me as well.

    The other aspect that I have struggled with is that skeptics, such as Dr. Novella have repeatedly stated that science is about making predictions.

    And where I think climate change seems to lack is substantive, specific, predictive value. I understand that there are a lot of variables to climate, some of which we know better than others – so making specific predictions may always be elusive to us. It just seems like there are some pretty big unknowns that scientific consensus have not been able to completely answer (what is long-term effects, timelines, temperature thresholds, etc.). And so there are vocal climate-change voices that are making these (rather doom-and-gloom) predictions – which only seems to reinforce a skeptical or cynical viewpoint?

  3. RickK says:

    Good post, Steve.

    There are various shades of “scientific concensus”. The scientific concensus on common descent is stronger than the scientific concensus on the impact of greenhouse gases. But both represent concensus. We say “based on the best evidence, science tells us THIS, so we should establish our policies accordingly” and people respond with “but you could be wrong – you can’t really be sure”. The possibility of error (always present in science) is unacceptable to many people.

    Do you think that there are personality types that simply can’t be “skeptical” in the way we think of the word? I’ve just come off a long thread arguing with evolution deniers. And there was a very distinct contingent that simply could not express themselves except in absolutes, and apparently couldn’t think in anything but black and white. Carl Sagan talks about cases where he’d say “I think there’s no evidence of aliens” and people would respond with “but what do you really think?”. Some (many) people need definitive answers. Skepticism requires the ability to find nuggets of evidence and truth within a sea of noise and bamboozle. That necessarily requires the ability to see shades of gray. I wonder if there are people for whom this is simply not possible – where the only acceptable mental state is complete certainty with minimal complexity. And can such people ever be skeptical?

  4. juga says:

    There is an added complexity with the climate change debate in that what we have been told is consensus, sometimes turns out not to be. For example, Phil Jones, a prominent climate scientist at the University of Easy Anglia Climatic Research Unit, was recently asked to confirm that “from 1995 to the present there has been no statistically-significant global warming”. See http://news.bbc.co.uk/1/hi/8511670.stm

    He replied “Yes, but only just”.

    Who can remember anyone from the “climate change consensus” saying this? It seems there are many advocates for action on climate change who have found it convenient to exaggerate the science and hide inconvenient conclusions, such as the one above.

    Of course, the single statement quoted does not mean there is not a problem. But there appear to have been too many cases where it has been felt the risks of inaction are too great to admit of any uncertainty. This is why people are suspicious of the “consensus”. It’s not that they disagree with the consensus, so much as don’t trust that it is a consensus.

  5. ccbowers says:

    Belief in bigfoot and UFOs are not really scientific questions (at least in how they manifest in society), but climate change is. They are not really comparable, other than for many people the opinions come before the facts.

    The problem is that climate change, when studied as a science, is more similar to economics than medicine or physics. Prospective randomized trials are often not possibile, they rely largely on models, and slight adjustements of assumptions (and there are often many) may lead to different conclusions. That does not mean that the science is useless it just makes the data more difficult to evaluate, and forces use to rely more on those who study the topic the most.

    This is a problem for skeptics who often want to evaluate the data themselves (or at least glance at it with a BS detector), and not simply listen to the consensus. This desire is to ensure that the consensus opinion is not due to like-minded people looking at a bunch of numbers, and seeing the same thing. That is not to say that a nonexpert can evaluate the data the way an expert can, but often the mistakes are not in the details but in the big picture. Perpective is what experts often lack, and this can be seen with a careful eye.

    I personally fall on the climate change issue the way I think many skeptics do: 1. the average global temperature is increasing 2. this increase is partially due to human activities 3. The percentage contribution of human activities is not known 4. some policy changes should be made to minimize human contribution 5. How drastic these policy changes should be is a topic of debate 6. be skeptical of people with very strong opinions on this topic

  6. tmac57 says:

    I think that humans are ill-equipped to deal with the immense complexities of our modern world. We did not evolve in an environment that poses the kind of mental challenges that we face today. Most of us are struggling with the day to day challenges of our personal lives, much less the bigger challenges that are looming at our doorsteps. In an attempt to deal with those bigger challenges(if we even bother trying), most of us will use simplistic rules of thumb that are fraught with biases, or just adopt the world view of our immediate culture with very little questioning. This is easier, and reduces cognitive dissonance.
    For those who seek a higher truth, there are many pathways and leaders who will gladly show you the “way”. And, for those who can tolerate nuance, they very soon realize that the more that they know, the more they will see that they hardly knew anything before that. And on it goes, where your increase in knowledge has the perverse effect of increasing your uncertainty.
    This isn’t to say that knowledge isn’t useful, as long as it is grounded in reality and rationality, it just means that trying to get an understanding of the world as a whole, will always amount to just a ‘snapshot’ of what there really is to know. And that should humble all of us.

  7. juga – that is a good example of why it is difficult to assess data outside one’s specialty.

    If you read the entire interview the picture is more complex. There is a warming trend for the last 10-15 year, of about 0.12C per decade – which is about what the trend has been. But, these measures just fall short of statistical significance – but this is because small changes won’t become significant until enough time has passed. The shorter the interval of time, the harder it is to achieve significance, and there may be no way for small changes to be significant.

    We will know in 5-10 years if the temperatures from 1995-2010 were significantly increased, but at that time we won’t have significance yet for 2010-2020. And I guess climate change dissidents in 2020 can make the same argument about the most recent decade.

    Also – a word on making predictions. This is not limited to predicting the future (a common misconception, and exploited by creationists). It also refers to predicting what independent data sets will show. The AGW model makes predictions about what ice cores will show, for example, and if the ice core data confirms the AGW model, it is said to have made an accurate prediction.

    My position is close to what ccbowers outlined. I also think that climate scientists have failed to adapt to the controversy of their discipline, and need to increase their transparency and communication. But also the dissidents are spreading a great deal of misinformation, in the mode of doubt and confusion. There are hard core denialists in the AGW dissident camp, and they have successfully muddied the waters of the debate.

  8. ccbowers says:

    Regarding “statistical significance.” I admit I know very little about climate change data, but isnt “statistical significant” a inferential statistics term. When we infer from a smaller sample to a larger group, we say whether or not the differences are statistically significant. But with climate data, we are not inferring from our earth to many earths, so what does “statistical significance” mean? Are we talking about how much variation we would expect by chance, and how do we determine this?

  9. Eugene says:

    Good blog post. I think an important factor for individuals studying topics outside of their fields of expertise is the type of narrative that they can construct that is meaningful to them. As you said the non-expert cannot understand all of the nuance of a topic, so they have to construct some way to justify their belief. I find that when I am in that situation I often try to come up with a short description (narrative) that is a broad brush mechanism for that phenomena.

    For example, for the human contribution to global warming I say something like the CO2 and other greenhouse gas emissions have been steadily increasing since the industrial revolution, so it must be warming the planet. I’m sure you could point out logical fallacies in that statement, but as far as I know it reflects scientific concensus and it is easy to understand and remember.

    A debate between experts involving complex narratives can be fruitful because both parties understand the nuance of the arguments, but that type of debate totally fails to convince non-experts. As a non-expert listener you will either be totally confused or you will reject the expert as arrogant.

    I find that a common strategy of those going against scientific concensus is to give a simple straight forward narrative that may be wrong, but that is easy to understand. It works because the ordinary non-expert cannot understand the detailed explanation by the expert of why that idea is wrong, and it leaves the listener without another simple narrative to replace the original (incorrect) one.

    Experts need to focus on ways of creating simple narratives that gives a mechanism for their conclusion.

  10. kelsken says:

    ccbowers: In the case under discussion, “statistical significance” refers to the question of whether the observed change in temperature is a an actual trend, or merely random variation. A gradual increase in temperature, if it exists, is difficult to see against a backdrop of noise found in year to year temperature measurements. Statistics are used to judge the strength of the signal against the noise. The more samples one takes, the better one can judge the existence of the signal.

    Steve: A real culprit in this entire climate change debate is inability of scientists to communicate effectively to the public. I don’t mean explain the intricacies of climate change – that is not really possible. But scientists are quick to say “we know” when I think they should more often say “the evidence suggests”. Scientists don’t discuss probabilities – and the whole climate change debate and our reaction to it is intricately tied to the probabilities. The questions that should be asked are “How likely is it to occur?”, “What are the consequences?”, “Can we stop it?”, “What will it cost?”. People can relate to those questions, not the question of whether or not x-number of ppb of carbon dioxide will occur in the atmosphere in 2023.

    Scientists have to know how their research will be used in the political arena. When a conclusion such as ‘climate change is occurring’ is presented and the conclusion is made that we must make radical changes to our lifestyles, scientists have to understand how that will be perceived and know that a certain segment of the population will immediately move into denial and debunk mode. And that another segment of the population will accept it as gospel and move into the preaching mode. And we end up with what we have today – endless debate. That works to the favor of the deniers, no doubt.

    As I was writing this it occurred to me to imagine a scenario in which astronomers identified an asteroid on a collision course with earth. What if there was some uncertainty whether or not the asteroid would hit? How would that dialog play out in public? “Let’s not spend a dime addressing this problem until we are sure the asteroid will hit!”. I assure you that a significant portion of the population would take that exact stance. Obviously an asteroid is much easier for people to understand than climate change, and I would like to believe the consensus would be to start addressing the problem immediately.

    Perhaps scientists need to learn how to make climate change look like an asteroid.

  11. johnc says:

    “Generally, non-experts tend to accept or reject anthropogenic climate change based upon their politics and world-view. That is a strong indication that most people are not assessing the science objectively, but are simply fitting the science to their ideology.”

    There are as many non-experts who think we’re destroying the world with co2 for exactly the same reasons.

    Until you can appreciate that this issue suffers from dogma, politicization and ideology on *both* sides, you aren’t fit to make objective observations and are clearly suffering from the same judgmental bias you’re seeing in those you disagree with.

  12. ccbowers says:

    I understand the big picture of expected variations versus trends, but if we are looking at a descriptive statistic measurement of temperature isnt statistical singificance the wrong term? Any change is real (assuming measurements are reliable and consistent), but we are wondering if that change is meaningful and part of a trend.

    Its a resolution issue as well, much like the stockmarket… watching moment to moment versus over months and years. Saying a stock’s increase in value is not statistically significant is not meaningful… the stock did increase. We want to know if this increase is part of a trend, and therefore meaningful over longer periods of time. I was just questioning the use of terminology not the meaning of the message. Perhaps I am just missing something, and the answer to my question is an obvious one. I am not accustom to use of statistics in this field.

  13. Nice post, Steve.

    It has always amazed me that libertarians don’t recognize how much their ideology influences their AGW views. I wonder: are there stats on what proportion of libertarians believe in AGW?

  14. CW says:

    (ccbowers, I like how you summed up your 6 pts – they reflect my own view. I hope you don’t mind but I am going to use that on my blog – and I’ll give you credit).

    “Also – a word on making predictions…it also refers to predicting what independent data sets will show. The AGW model makes predictions about what ice cores will show, for example, and if the ice core data confirms the AGW model, it is said to have made an accurate prediction. ”

    This is what I refer to, about making predictions. But from my understanding, and this came to light during Climategate – is that scientists were frustrated because their current observations were not adhering to their models.

    (Meh, I don’t want to steer this post into a debate on climate change – it’s not the spirit of the post).

  15. tl;dr says:

    This is off-topic.

    Mr. Novella, I want to thank you for the Youtube “lulz.” It seems you specifically (and other SBM colleagues of yours) have driven some irate lunatic and proponent of homeopathy to make a ranting Youtube video against you and other SBM “cranks” like yourself who “are not” even real “medical practitioners”.

    I’m sure you get angry emails from people like this often, but I just wanted to say thank you for inadvertently causing people like this to share their stupidity for everyone’s entertainment.

    He’s adorable: http://www.youtube.com/watch?v=mDxQ272yPvs

  16. CivilUnrest says:


    In a previous post about climate change, Dr. Novella described some of the difficulties inherent in measuring the “global climate”. These include formidable challenges such as (I’m paraphrasing heavily, but I think my gist is correct) “Where do we gather the data from and how to we weight it?” and “What does the average global temperature even means?”

    So, it’s not just the trend that must show significance, it’s the data as well.

    (RE: are there some people who can only think in absolutes?):

    I wrote my senior thesis about the differences and similarities between the way we naturally come to believe something is true and the way science comes to conclude that something is probably true.

    One of the most interesting tidbits I learned was that the amygdala (sympathetic nervous system / fight-or-flight response) is activated by stimuli that we tend to want to be rid of. In other words, when we find ourselves confronted with danger, the amygdala kicks into gear so that we can either defeat or escape the danger. In essence, it is a behavioral negative feedback system. The stimuli that activates it triggers behaviors that tend to remove the stimuli (or remove us from it, as the case may be).

    While the amygdala is activated by my types of stimuli (angry or horrified human faces, for instance), it is MOST STRONGLY activated by stimuli which are potentially threatening, but not overtly so. In other words, uncertainty is the least desirable situation in which we can find ourselves. Our brains hate it when we can’t categorize something definitively, and we go to great lengths to avoid such situations. I’m sure many of you have experienced this when you have tried to convince someone that one of their beliefs is demonstrably false. People are always resistant when asked to give up a firm, comfortable conclusion for the wild world of uncertainty.

    This isn’t a terrible trait. In fact, it makes a lot of sense. Weighing the evidence about whether or not the rustling in the jungle is a tiger or just the wind isn’t a particularly good tendency. We evolved in a world where better-safe-than-sorry was a survival strategy.

    My point (sorry it took me so long) is that it takes a good measure of mental and emotional discipline to be perfectly content with the answer “I’m not sure, it could really go either way”. Our brains want to draw conclusions and be done with the issue; leaving things unresolved is not our strong suit.

    I wish that, in my research, I stumbled upon some solution to this seemingly intractable problem, but it is not the case. All I can say is that it takes a healthy desire for truth and accuracy to overcome our innate tendencies toward a quick and easy conclusion. How to instill such a desire into the larger population is a problem that I don’t see us solving anytime soon.

  17. weing says:

    The problem that I see with the global warming debate is not whether it is real or not but whether it is good or not and for whom. Here, there is an agenda being pushed. I’m oversimplifying here; yes, it’s bad for Florida, small islands and the coastlines but great for people like the Inuits and others currently living in cold climates. Trying to reverse global warming would serve to keep these people down in favor of the status quo.

  18. SimonW says:

    I’m doubtful about calls for openness and transparency in Climate Research, the interview with CJ sums it up well – read his papers with more attention than his emails.

    My belief is that Climate science like Vaccine science is unusually open compared to other forms of science. I don’t have hard numbers, but my experience is that more climate papers are available for free of charge download, and a lot more datasets are available than I see in most other areas of research. This is in part because a lot of it is state funded, but I think also deliberate policies of openness are already in place, and in many cases the data and research has been published by the IPCC.

    I don’t have a problem with more openness I’m simply skeptical that it will change any minds. It may be that education efforts might succeed but probably not on relevant timescales. Certainly the more knowledgeable a person is about climate science the more likely they are to accept anthropogenic climate change is underway.

    I’m reminded of the surveys of belief in a personal god of scientists. The proportion believing has fallen sharply since 1914 (~27 to 7), but I don’t believe there has been any new relevant evidence for or against the existence of a personal god.

    There is also the question of how much does it matter what the wider view on climate change is? It may make it harder to force through policy, but largely it is governments that need to provoke action, and the governments seem pretty much convinced by their climate scientists.

  19. tmac57 says:

    johnc says:”There are as many non-experts who think we’re destroying the world with co2 for exactly the same reasons.

    Until you can appreciate that this issue suffers from dogma, politicization and ideology on *both* sides, you aren’t fit to make objective observations and are clearly suffering from the same judgmental bias you’re seeing in those you disagree with.”

    Read Dr Novella’s statement carefully again:
    “Generally, non-experts tend to accept or reject anthropogenic climate change based upon their politics and world-view. That is a strong indication that most people are not assessing the science objectively, but are simply fitting the science to their ideology.”

    See the words “ACCEPT” or “REJECT”. He is clearly stating that the tendency for NON-EXPERTS (on EITHER side) is to view the science of AGW through ideological filters.

    Having said that, the opinion of non-experts or even experts , is not what determines the reality of the of anything. Science is not a popularity contest. I personally give more weight to the scientific consensus in the matter of AGW. I will freely admit to a liberal bias, so my opinion as a non-expert has no weight in the debate. I really do genuinely want to be on the side of the truth, however, and nothing would please me more that to find out that there is nothing to worry about. I’m not there yet.

  20. CivilUnrest says:


    I just watched your video. Wow. I think my brain might explode.

  21. Damned Skeptic says:

    I’ll just throw this out there and see if anyone feels like responding. How did you determine that there is a scientific consensus on AGW?

  22. eean says:

    @weing that’s an ethical quandary with any on-purpose geoengineering as a response to global warming. Actually the problem presents itself with any asteroid deflection attempt as well. I really like this asteroid analogy. 😀

    But obviously just cutting C02 emissions shouldn’t have any ethical trouble… we don’t owe it to Minnesota to warm the earth for them.

  23. ccbowers says:

    It seem that you are forgetting that:

    1. Limiting CO2 emissions will not maintain a status quo. The world has not been and never will be a static place. Also, we will not be completely eliminating CO2 emissions in the near future
    2. Accelerated warming will not likely result in an equal number of winners and losers, but accellerating any change will likely cause a net negative effect. This is because people have congregated in cities along coasts and rivers and areas in the world that have weather that is desirable for a variety of reasons. We have already adapted our living based upon how things have been recently. If change is accellerated, then people will be forced to adapt quickly which may have a significant cost. For example, losing a costal city will not likely be offset by making Siberia a more hospitable place. Not to mention that these effects are not that predictable. Many places may cool, only offset by more places warming.

  24. weing says:

    “But obviously just cutting C02 emissions shouldn’t have any ethical trouble… we don’t owe it to Minnesota to warm the earth for them.”

    Agreed. But do we owe it to Florida and the residents of tropical paradises to cool the earth for them?

    “The world has not been and never will be a static place.” Why do I get the feeling the climate change missionaries are pushing legislation to stop it, implying we can have a static place?

    “Not to mention that these effects are not that predictable. Many places may cool, only offset by more places warming.”

    Agreed. That’s why we need to keep studying this and keep developing better models.

  25. SteveA says:


    Thanks for that tmac57. I too was wondering what part of ‘accept or reject’ johnc didn’t understand.


    “A real culprit in this entire climate change debate is inability of scientists to communicate effectively to the public. I don’t mean explain the intricacies of climate change – that is not really possible. But scientists are quick to say “we know””

    I’d dispute this. In my experience the vast majority of scientists are very careful to explain the uncertainties surrounding their work. It’s the media’s reporting of their findings that usually spoils things. In the hands of a sub-editor or reporter dark grey usually becomes black, and light grey, white.

  26. eean says:

    @weing who is talking about cooling the earth? even the purposeful geoengineering ideas (as opposed to the accidental geoengineering we’re doing currently) have the goal of “running on treadmills” trying to get the status quo.

    actually, what the heck are you talking about?

  27. weing says:


    Since I see myself as benefiting from global warming, I want to be compensated for foregoing those benefits.

  28. kelsken says:


    After re-reading my comment, it was a bit strong (perhaps I should have said ‘a contributing factor’ instead of ‘a real culprit’). But as important as it is to ‘do the science’ and unearth the facts, it is even more important to communicate those ideas effectively to the public. And in the case of climate change that has been, by and large, a big fail.

    Abraham Lincoln has been quoted:

    “When I am getting ready to reason with a man, I spend one-third of my time thinking about myself and what I am going to say and two-thirds about him and what he is going to say.”

    Science communicators must spend more time thinking about what the denialist will say.

  29. bleroy says:

    Dear Dr. Novella,

    Here’s one thing that has been bothering me for a while which might hopefully make for an interesting follow-up post.

    Who decides who is a member of the scientific community? (and thus, who should count and be part of the “scientific consensus”)

    For example, we often object to pseudo-scientists that if their ideas have value, they should just get them published in a peer reviewed journal. But now they have understood it a little too well and are creating their own “peer-reviewed” journals. Of course, their peers are nutcases like themselves but they are giving to the general public most of the signals of good science. How is a non-specialist or even non-scientifically literate person going to tell the difference?

    Of course, there are titles, and it’s expectedly and rightfully difficult to get something taken seriously in science if you don’t have at least a doctorate in the field. But again, phony titles are just as easy to create as journals, especially as authorities such as the state of Maine is authorizing titles such as N.D., spreading more confusion in the public about what’s legitimate science and what’s just not.

    Again, it seems like we are back to a need for authority: authority to sanction a publication as serious, and authority to dispense titles. And maybe authority to judge authority?

    Any idea around that?

    Bertrand (PhD, but that doesn’t make me any less clueless on this)

  30. CivilUnrest says:

    @ weing

    “Since I see myself as benefiting from global warming, I want to be compensated for foregoing those benefits.”

    You can’t reasonably say that you’ll benefit from global climate change acceleration (a more accurate description of the current situation than the simplistic term “global warming”). As the global weather patterns change, local weather patterns will simply become MORE unpredictable until the planet reaches a new equilibrium.

    What I am getting at, is that living in a cold climate won’t guarantee you’ll benefit from climate change. Look at the snow storms that have battered Europe and the US east coast. These are occurring because the very cold air normally trapped (by strong circular currents) above the north pole is breaking through its barrier and blanketing us.

    Global climate change won’t just make the whole world warmer, it will make all weather much weirder. While I think Friedman’s is a simplistic view (and his re-naming suggestion is quite misguided), the idea behind the paper is quite relevant.

  31. steveisgood says:

    For more RFK Jr. Craziness, Skeptic North has a piece about his out-to-lunch insights with regards to mercury and vaccines. Click Here. (written by yours truly)

    Good post, Steve. I was JUST in a bit of a row over this very same argument.

  32. weing says:

    Aw come on. Weird weather? I’ve seen worse snowstorms and I’m sure even worse have occurred in the past, multiple times. I have land that I’m hoping will be prime beach front property when the sea level rises. The Inuits stand to make a killing from a Northwest passage and a really green Greenland.

  33. splicer says:

    I listened to an interview this week with someone from the U.S National Weather Service and they are forming a dept just for Climate Change. It should be up and running according to the interview by October of this year.

  34. sonic says:

    From Feynman–
    “What is the fundamental hypothesis of science, the fundamental philosophy?… the sole test of the validity of any idea is experiment.”
    In the case of climatology the experiments can’t be run.
    This means that the usual means of determining the truth scientifically (experiment) is not available in this subject.
    This is why we talk of consensus– we can’t see who is correct by experiment. This is a human group problem (politics will be involved when experiment is not the determining method of discovery.)
    It makes sense to me to be particularly skeptical in this kind of situation.

  35. cja says:

    Problem with the RFK comparison. So he agrees with the scientific consensus on climate change, but thinks that the scientific consensus on vaccines is the result of fraudulent scientists.

    There are a lot of people who are skeptical about climate change who don’t think that climate scientists are frauds. They think, well, I know a few things about physics, and I know a thing or two about economics, and the “science” in climate science seems to be somewhere between physics and economics. So I’m not sure how seriously I should take the conclusions.

    It’s not fraudulent to take to develop the best available framework for making long-term predictions about the climate, and then be very confident about the predictions that you make while operating within that framework. But it’s hard to judge how adequate the framework is if you are a scientist who has already subscribed to it. And at times it seems that unless you are willing to get a PhD, and thensome, studying that framework, you won’t be judged competen to critique that framework. Not many people spend a decade building a reputation in a field whose well accepted framework they desire ultimately to rebuke. Therefore, the scientific consensus about the framework (as opposed to specific theories based on it) will be very slow to change.

    So i can say that we are 95% certain that the earth will warm 6 degrees over the next hundred years, in the same way that an economist can predict with 95% certainty what housing prices will be in a year. And naturally that will garner skepticism from people outside of climate science or economics. Important frameworks of climate science have been around for maybe 20 years, whereas the framework of physics have been around for centuries. (A key framework in climate science is building a theory and testing it against computer modeling, a very recent capability. Physicists didn’t confirm relativity until they had empirical confirmation of one of its predictions, light bending around the sun, a framework that has been around for years; in this sense, the once “radical” theory of climate science is more akin to evolution, which was an entirely new science, though a least built on empirical results, than to relativity).

  36. cja – I disagree. You are stating why some people might disagree with the science. But my analogy was to the explanation for the consensus. You either have to believe that you know better than 95% of climate scientists, or that there is something wrong with the consensus – a systematic bias at the very least, and a conspiracy at worst.

    This is exactly analogous to the anti-vaccinationists. They reject the scientific consensus as either biased and/or a conspiracy. And they have their scientific arguments (although incorrect ones) also – just like AGW dissidents. There is also a spectrum of belief, with varying degrees of conspiracy mongering vs just not getting or trusting the science.

    The fact is – some AGW deniers endorse the same kind of conspiracy theories that RFK does about vaccines. Pat Buchanan has said and written that AGW is a hoax designed to transfer money from wealthy nations to poor nations and enact a socialist agenda.

    Further, I think medical science and climate science are similar in how messy their frameworks are, and how difficult they are to understand by non-experts.

  37. tmac57 says:

    For anyone interested, here is a link to an NPR story on The Cultural Cognition Project and perceptions on AGW. It runs about
    4 1/2 minutes (also has the text):

  38. Joseph says:

    But with climate data, we are not inferring from our earth to many earths, so what does “statistical significance” mean?

    That’s not exactly right. There are some inferences you can make by looking at other planets. For example, it’s not that hard to estimate the mean temperature of a planet without an atmosphere rather accurately, like Mercury, or our own moon. You do this with Stefan-Boltzmann’s law.

    What you find for Earth using the same method is that it’s about 30C too warm. That’s because of its low emissivity, otherwise known as “natural greenhouse effect.”

  39. Joseph says:

    Any change is real (assuming measurements are reliable and consistent), but we are wondering if that change is meaningful and part of a trend.

    The problem is that there’s weather noise. Climate is not the same as weather. So even if measurements are trending upward, you need to determine if the trend is part of a long-term trend or simply noise. You use statistics for that.

    That’s also the case when people claim “no change between years X and Y.” I once wrote an analysis on that:


  40. weing says:


    Thanks for the link. I loved the coastline simulations on that website.

  41. Damned Skeptic says:

    Mr. Novella,
    You say “95% of climate scientists”, so I’m wondering how you arrived at that number.

  42. Joel says:

    @Damned Skeptic

    “How did you determine that there is a scientific consensus on AGW?”


    First, simply ask. “The IPCC, the NAS The American Meteorological Society, the American Geophysical Union, and the American Association for the Advancement of Science (AAAS) all have issued statements in recent years concluding that the evidence for human modification of climate is compelling.”

    Second, look at the published data:
    “. . .by analyzing 928 abstracts, published in refereed scientific journals between 1993 and 2003, and listed in the ISI database with the keywords “climate change”. . . none of the papers disagreed with the consensus position.”

    “Admittedly, authors evaluating impacts, developing methods, or studying paleoclimatic change might believe that current climate change is natural. However, none of these papers argued that point.”

    So there you go, that’s how we know there is a consensus.

  43. Damned Skeptic says:

    In summarizing the article, you’ve created a quote that didn’t exist in the article, and left out pertinent quotes that are about consensus. More to the point is this, “…IPCC states unequivocally that the consensus of scientific opinion is that Earth’s climate is being affected by human activities…” and this quote from the National Academy of Sciences (NAS) , ” ‘The IPCC’s conclusion that most of the observed warming of the last 50 years is likely to have been due to the increase in greenhouse gas concentrations accurately reflects the current thinking of the scientific community on this issue.’ ”

    The NAS report doesn’t claim that the committee verified any IPCC claim about scientific consensus, nor does it explain how they reached that conclusion. Because the committee members are experts doesn’t make the statement a fact. Otherwise, deferring to expert consensus becomes deferring to what’s written in the NAS report.

    The same applies to the IPCC. Just because the assessment states there is consensus doesn’t make it true. What did they do to confirm that a consensus exists? Which scientists do they consider experts? What evidence reflects the consensus? It’s possible that the assessment answers these questions, but I wouldn’t just trust that it does.

    The Oreskes essay does explain her method for confirming a consensus, but some questions can’t be answered without seeing the study. And seeing the study costs money. Even if you don’t question her methodology, basing a belief in consensus on this essay doesn’t strike me as skeptical inquiry.

  44. Joel says:

    What you were meant to take away from this was not that an overwhelming majority of climatologists believe global warming is anthropomorphic. Frankly, the consensus itself is meaningless.

    What this article points out is that they aren’t publishing. If there is a group out there large enough to break consensus, I can’t find any evidence of their existence in the literature.

    Whether or not there is a consensus is meaningless. Hell, even if 90% of climatologists don’t support AGW, it doesn’t mean anything if they just twiddle their thumbs and throw in the occasional “Nope” from the corner of the room.

  45. topstep says:

    Excellent post. So many of my discussions with true believers – be they religious, anti vax, 9/11 Truthers – come down to the notion of “What is truth?” “How do we KNOW anything?”

    I think consensus of expert opinion is one of the most powerful tools we have for finding “truth”. (Of course, it is imperfect – something that unsettles those who see the world in black and white.) But it is the best we have.

    When having these endless discussions with true believers, I sometimes ask them how they would react if they or a loved one were arrested for a serious crime that could put them in prison for the rest of their lives. What level of evidence would they require from their accusers? More often than not they become instant skeptics, saying they would require solid evidence, properly acquired by experts in their field. Atheists in a foxhole? How about evidence deniers in a prison cell?

  46. Damned Skeptic says:

    I’m feeling a little embarrassed because Steven Novella wrote an thought-provoking philosophical blog which I didn’t address. I was more interested in seeing if people who claim AGW consensus have applied the types of questions he raised: “…what do scientists believe, what do they agree on, and where is there legitimate controversy? How sure are they of their conclusions, and how strong is the consensus on any particular question?”

    Let me redress my neglect a little. I wonder how many people read the following quote and thought it applied to them: “Generally, non-experts tend to accept or reject anthropogenic climate change based upon their politics and world-view. That is a strong indication that most people are not assessing the science objectively, but are simply fitting the science to their ideology.” If that’s true then probably not many people thought it meant them. This brings me back to my interest. Are most people that accept or reject consensus doing the same thing?

  47. einniv says:

    I realize that this article was more about being careful about not letting our world views drive which science we accept and not about climate change per se. However, I did notice some people have some wrong notions about the science so I wanted to give a link to a blog I recently wrote, mostly for family and friends who don’t have the time or inclination to investigate such things. I’ll say up front that most of the blog was just rewording other sites information and I give links to those sites in the blog entry. (I don’t want to anyone to think I am taking credit for the work of others which most of the blog is heavily based on).

    Anyway, there are squabbles above about the recent statements about increase in temperature not being quite statistically significant. I just want to point out that the climate change argument does not necessarily hinge on that information anymore. Especially in the last decade there has been direct observation that has shown conclusively that 1) CO2 is leading to heat being trapped and 2) the earth as a whole (including Oceans which everyone always leaves out!) is accumulating massive amounts of energy.

    As I put it in my blog the case for climate change is basically this:
    There are gases in the atmosphere that absorb and trap long wave radiation keeping it close to the earth. CO2 is one of these gases. The concentrations of CO2 in the atmosphere are increasing. The increase is due to human activity. Observation shows the amount of radiation escaping the planet is in fact going down. Observation shows the amount of radiation re-emitted toward the earth from the greenhouse gases are in fact going up. Observation shows the earth’s land, atmosphere and oceans are in fact accumulating energy (heat).

    I then give graphs which show the results of the direct observations. The link my blog entry is:


  48. James Wight says:

    I generally agree with Steve’s views on authority and scientific consensus. There are a couple of other points about climate science that I’d like to add.

    In response to cja’s comparison of climate with economics: Climate models are based on physical processes, not the murky world of human psychology that economists have to deal with. For this reason, I’d say climate science is considerably closer to physics than to economics.

    With regard to ccbowers’ points 2 and 3: if you’re talking about the modern warming of the last 35-40 years, then it appears the human contribution is actually more than 100%:


    Models including only natural forcings predict a slight cooling over that period (during which solar activity was relatively flat and there were a couple of major volcanic eruptions). Only when the anthropogenic forcings are added do the models predict the rapid warming that has in fact occurred. (Having said that, the warming in the early 20th century was probably helped by natural causes such as an increase in solar activity, at a time when greenhouse gas forcing was much lower.)

    Incidentally, climate change is not necessarily a good thing for the Inuit, considering that the fastest warming is occurring in the Arctic, and this threatens ecosystems the Inuit rely upon.

  49. Damned Skeptic says:

    James Wright,
    Are you sure you wanted to say that humans contributed more than 100%? That doesn’t seem possible.

  50. James Wight says:

    What I mean is that in the late 20th and early 21st centuries the human contribution was positive and the natural contribution was slightly negative. So the human contribution was actually greater than the resulting warming.

    As for the warming during the 19th and early 20th centuries, the human contribution was smaller, and natural influences probably played a bigger role as the Sun was coming out of a minimum and volcanic activity was quietening down.

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