Tuesday 6 May 2014

Climatology is a mature field

Manure pile
Apparently I wrote something controversial in a comment at Judith Curry's place (Climate Etc.).

Judith Curry wrote:
The point is that you can’t neutralize plausible alternative interpretations of the available evidence from diminishing the scientific ‘consensus.’ It only takes one such argument, and one person making it (but in fact there are numerous arguments and a substantial number of people making them).
To which I replied:
In practice it will likely take more than one Galileo or study. Also the refutation of classical mechanics by quantum mechanics and relativity did not change many things we already understood at the time. It allowed us to study new things and ask new questions. That was the revolution.

Climatology is a mature field and new findings will more likely change the complete picture only little. The largest uncertainties are in the impacts, improving our understanding there will have to be done one impact at a time. And more likely, one aspect of an impact at a time.
It is a pity that people did not respond to my claim that large scientific changes (paradigm changes) tend to enlarge the scope of science, rather than to invalidate more practical previous findings. The claim that climatology is mature, however, was too much for many.

Judith Curry returned:
1. Climate science is NOT a mature field. Stay tuned for more and more surprises . . .
Hard to answer such a argumentative heavy weight comment.

There are also some sensible people there, for example Michael answered Curry:
The second [surprises] is not in any way ruled out by the first [maturity].
There are plenty of new discoveries, even in mature fields.
It it interesting that Curry welcomes surprises and uncertainty so much. The surprises are what worry me the most. I guess that is my conservative side. People have worried about climate change through the ages because the climate is so important to us. Now we are messing with the climate as if we know exactly what we are doing and it's gonna be great.

Fitting to the level of the "debate" in the comments at Climate Etc., dlb wrote:
Perhaps he meant a manure field?
Glad to know I wasn’t the only one whose jaw dropped after reading that.
Most others also just expressed their disbelieve. What comes closest to an argument is: scientists (economists, politicians) have been wrong before, thus climate science is not mature. Okay, maybe I am too generous calling that almost an argument. I hope I did not miss any arguments, the "discussion" was somewhat derailed by people arguing against the greenhouse effect. Also fitting to the level of the comments at Climate Etc. I have no idea how an improvement in scientific understanding should result from that blog.

What makes a scientific field mature?

So what is a "manure" scientific field? Three important aspects are probably: mass, time and networking.

But let me first explain what maturity is not. Calling a field mature does not mean that no discoveries will be made any more, it also does not mean that predictions are perfect and confidence levels are zero. Science is not religion, if you cannot handle uncertainty, you should not be debating science.

Let's contrast a mature with a young science. For example the beginning of discovery of the greenhouse effect. From Wikipedia: "The existence of the greenhouse effect was argued for by Joseph Fourier in 1824. The argument and the evidence was further strengthened by Claude Pouillet in 1827 and 1838, and reasoned from experimental observations by John Tyndall in 1859, and more fully quantified by Svante Arrhenius in 1896." These single scientists could easily have been completely wrong. The years indicate that they did not communicate with each other about the topic. There was thus no competition for who was smarter. At that time it could have happened that someone found that the arguments of Fourier were nice, but the observation do not show the effect. That the measurements of Tyndall were carefully performed, but his instrument does not measure what he thought it did. That there is a greenhouse effect, but contrary to the findings of Arrhenius CO2 is completely irrelevant. And at the time, it would have been possible that negative feedbacks are so strong, that any additional radiative forcing by CO2 does not influence the surface temperature. And a Galileo might have found a stupid calculation error in the works of any of these scientists.

Mass. There are thousands of climate researchers and in I just found 112,598 articles on the Web of Science about "global warming" or "climate change". These article will not all be studying climate change, but a large part will. That alone makes a stupid calculation errors nearly impossible. Having multiple people working on the same topic also provides a sparring partner to discuss and compete with. The weight of the evidence is huge, not comparable to previous times the media or scientists called alarm or called for more research.

Mass allows some scientists to specialize. For example, some people work on radiative transfer for most of their career. They study the importance of various assumptions, try out various methods of solving a problem, solve various problems with radiative transfer (greenhouse effect, passive and active remote sensing) write textbooks, collaborate with scientists working on radiative transfer in other fields, build joint validation programs for radiative transfer codes, and so on. A specialist is less likely to make mistakes as a newby, the networking weaves a scientific field into the the complete network of scientific theories, methods and tools. (Nothing against newbies, a growing science will have lots of them and they can help with fresh ideas.)

If the physical basis of climate change were found to be wrong, this would likely affect many other sciences via this network. Anything is theoretically possible, but this sure makes it much less likely. The first thing many climate change dissenters learn about is the greenhouse effect itself. Unfortunately many get stuck with this very well connected theory. It is much more likely to find problems with aspects that are specific to climatology, the climatological response of the oceans, vegetation and clouds, for example. What will happen with extreme weather, and all the various impacts? These are difficult questions, but they are not questions that are solved by one Galileo paper. If you want to be that guy, please have a look at such topics, not the greenhouse effect and make the "debate" at least a little more intelligent. Even better, take an objective look at these topics, that increases the chance you will contribute to our understanding of climate change.

Time. Time is important first of all as the amount of time a specialist spends on a topic. Secondly, science takes place in the scientific literature. Performing a study, writing it up and getting it published can easily take a year or longer. While the main ideas might be known from conferences, an idea can only be fully tested after publication. And the response again easily needs a year. Thus science takes time. Also creativity takes time. The longer no new idea turns out to change the main picture much, the less likely it becomes that that happens. And also for creativity mass is important, more people have more funky ideas.

How does a mature scientific field work?

Discoveries. That does not mean that no new discoveries are made. In my own field homogenization we have made spectacular progress the last decade. Modern homogenization methods are now twice as good as traditional ones. Better methods have increased scientific confidence that the temperature trend is robust, but did not change the trend much. (This may be different for daily data, used to study changes in extreme weather, where non-climatic changes are expected to be more important.)

While the homogenization of the annual means is a "manure" science, the homogenization of daily data is in its infancy. Some of my colleagues object to me calling annual homogenization mature, because they still have many ideas to improve it. I hope that after this post, people will understand that I do not see that as a contradiction. Science is never finished, but that does not mean that we know nothing.

Bias. In the beginning, when there is just one person or a few groups working on a problem, they may be tempted to exaggerate the importance of their problem. Most scientists are rather conservative when it comes to making strong claims, but scientists are also humans and some may be tempted by external incentives, although disingenuous pseudo-skeptics like to exaggerate this problem. Calling something a problem helps attracting more people and funding. Exaggeration is relatively easy in this stage as the uncertainties are high and are high due to ignorance.

When a field gets larger, every speciality has an incentive to exaggerate the importance of their speciality. A solar physicist is tempted to claim it is the sun, but hindered by the evidence. I went into science to understand the world a little better and maybe to show off my skills. Were I driven by monetary incentives, as a naive economist might expect, I would be tempted to claim large uncertainties due to non-climatic changes, that would make my field more important. Even if Anthony Watts thinks otherwise, it would be bad for my career to claim that climate data is fine. Making unscientific claims WUWT-style would hurt my career even more and take the fun out of being a scientist.

Because of the incentives of the solar physicist to claim that global warming is due to the sun and my incentive to claim it is non-climatic, the chance of a bias in the big picture is much reduced for a "manure" science. Our understanding will keep on improving and estimates will change, but at this stage I would no longer expect any biases in the basic science: the changes will go in any direction.

Judith Curry likes the word uncertainty. Towards other scientists she can claim that she intended it the way science uses the word: we do not know the exact value, it lies in a confidence range. It could be higher, it could be lower. To her audience that sounds like: they know nothing, they are not sure about climate change, maybe there is no problem after all. Curry's audience hears bias! And is shocked that someone dares to call climatology a mature science.

Let me close with an interesting tweet on the topic of terms used differently inside and outside the scientific world. (The figure comes from Communicating the science of climate change by Richard Somerville and Joy Hassol. h/t Lars Karlsson)

* Some of the comments have been edited for readability.
** Tip: do not search for "mature" Flickr images.


  1. Seems a good time to point to Asimov's Great essay on the relativity of wrong

  2. I suspect that you in a number of places write "manure" when you mean "mature", like in "What makes a scientific field manure?" Maybe its on purpose, but it gets a bit confusing.

  3. Thanks Dan, that is a beautiful text by Asimov. Good to hear it from someone outside of the climate "debate": Copernicus switched from an earth-centered planetary system to a sun-centered one. In doing so, he switched from something that was obvious to something that was apparently ridiculous. However, it was a matter of finding better ways of calculating the motion of the planets in the sky, and eventually the geocentric theory was just left behind. It was precisely because the old theory gave results that were fairly good by the measurement standards of the time that kept it in being so long. ...
    Naturally, the theories we now have might be considered wrong in the simplistic sense of my English Lit correspondent, but in a much truer and subtler sense, they need only be considered incomplete.

    Lars, that is a small pun on the quality of the comments at Climate Etc. I will reduce the number of instances to make the post a bit more readable.

  4. Victor, I suggest you put the word "manure" in ironic quotation marks.

  5. Nevertheless, it's good to rattle folks once in a while, just to check if they are awake.

    Keep up the good work Victor.

  6. Victor, thanks for another interesting post. I think your explanation of why Judith Curry likes the word 'uncertainty' so much is right on the money, and kudos to Dan for the Asimov link -it's a beauty.

    For me, the most striking feature of the discussions between you and those at Climate Etc. is the strong theme of 'gatekeeping', with you perceived as putting up the gate around science, and the bloggers perceiving themselves as demanding entry.

    It seems to me this rests on certain ideas of how much work a person should do in order to earn entitlement to participate in the debate. Your exchanges with Steven and Burl really illustrate this:

    Steven and Burl seem to think they have already done enough work, that their viewpoints deserve due respect -and you of course, imply "no, you guys haven't done enough work, so taking you seriously is giving you too much credit"

    There are two themes here, that I suspect are equally distasteful to the denizens of Climate Etc, and the other crowd science blogs:

    First, the point you have often made, that there is a hierarchy of knowledge in science. Older, established ideas cannot simply be overturned in the way new theories or findings can.

    Second, that a person must demonstrate they understand the fundamentals, before they can expect equal time from people who have already put in that work.

    Neither of these are 'democratic' in the naive 'you don't have a right to refuse me a seat at your table' way that we endlessly see on the net nowadays. But both of these are surely preconditions for any serious and reliable science to be possible. At the end of the day, it is the difference between citizenship as a claim of entitlement (as though citizenship were a consumable), and citizenship as a responsibility to contribute.

  7. I would guess that claiming "gate keeping" is a forced move for the climate "sceptics". Once you claim that mainstream science is wrong and you have the better explanations, you have to explain why your "better" "science" is not in the scientific literature.

    Up to now I have not seem convincing evidence of gate keeping. There is a stupid stolen email in "Climategate" about keeping an article from the scientific literature (gate keeping did not work :-) ) out of the IPCC report (but in was in the report).

    And now we have Bengtssongate (let's keep on deflating the term gate :-) ) with the claim of a suppressed manuscript. Not only is this not supported by the two published reviews, which give many scientific reasons why the manuscript is flawed, now also Bengtsson himself admits that this is not a sign of gate keeping, but completely normal scientific practise. Some selective journals only publish a few percent of the submitted manuscripts, then you move on an go to the next one if the reviews were not too damning.

    Two small corrections: "First, the point you have often made, that there is a hierarchy of knowledge in science. Older, established ideas cannot simply be overturned in the way new theories or findings can."

    Older ideas (hypothesis, theories) can be simply overturned, even if it becomes less likely with time. My main argument was that this does not mean that much of our understanding of the study topic is suddenly wrong. A new theory more typically adds to our understanding rather than destroy previous understanding (completely).

    Second, that a person must demonstrate they understand the fundamentals, before they can expect equal time from people who have already put in that work.

    It is good scientific practise to do so. And it surely helps an idea gain credibility and it thus helps credible people investing their time to study the idea. It also makes it much more likely for you to see the strengths and weaknesses of your idea and to present it better. However, I would not go as far as to say that it is mandatory. It is helpful.

  8. Despite the awesome chart of misinterpreted scientific words by the public, there seems to be big another big misunderstanding you glossed over. That would be the phrase "Mature Science/Field", and what it means among scientists.

    When I hear people speak of a Mature Field they often mean that there is little to be discovered left, it has become very niche, or funding has dried up somehow; not a very positive word to say the least. This seems to be not to far from your own opinion of the word in your original statement, "Climatology is a mature field and new findings will more likely change the complete picture only little". Hard to image getting funding if your not going to change much about our understanding of the complete picture...

    You then go on and make this article about how it's a really good thing to be a mature field, and great things are happening, and never address this obvious stigma and real debate about mature fields.

    Besides you're glossing over of the debate, can we really say we understand the whole picture of climatology? Can we really say whether the North Atlantic Circulation will shut off, where the next drought will occur, where the next forest will turn into a desert, what will be the strength and timing of the next El Nino, when the next ice age will occur? Not with much certainty at all, and the idea that the impacts of climate science are the only uncertainties is ambiguous and misleading.

    Not only is climatology not a mature science, I believe no field is. I think the term is used by scientists to refer to fields that are not there own as being inferior because they can't see the use in discovering any more; which is kind of naive. Who is to say that there will be no revolutions in a certain field? Only someone who knows everything there is to know about that field; I think few would be so confident to say that they had even close to that knowledge about any field.

  9. This is a beautiful example of a strawman. First exaggerate someone's claim and then attack that exaggeration, which is much easier.

    Not only is climatology not a mature science, I believe no field is.

    So how would you describe the difference in maturity of scientific fields? Or do you see no difference whatsoever between classical mechanics and climatology? I would argue that classical mechanics is even more mature and think it would be nice to have a word for that.

    You then go on and make this article about how it's a really good thing to be a mature field

    I am claiming that the basis is mature. Where did I write that it is a good thing? It just is.

    Who is to say that there will be no revolutions in a certain field?

    Did you read the piece?

    "There are plenty of new discoveries, even in mature fields."

    "Calling a field mature does not mean that no discoveries will be made any more, it also does not mean that predictions are perfect and confidence levels are zero. Science is not religion, if you cannot handle uncertainty, you should not be debating science."

    "That does not mean that no new discoveries are made."

    Classical mechanics was quite mature before quantum mechanics and relativity came by.


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