Small amounts of very active substances can have large effects, but this doesn’t prove that carbon dioxide is such a substance

Two things came together today. First was A Guide to Understanding Global Temperature Data by Roy Spencer, which I read a week or so ago. Second, I was pointed to an article in the Guardian in which a white paper written by the same Roy Spencer was being rebutted.

Initially, it was not clear which paper was referred to and, although there were also 13 questions involved, the rebutted items didn’t seem to be similar to the guide that I read earlier. So I was a bit confused. Did Spencer wrote another white paper in which he also used that 13-questions format, but with other arguments?

Becoming curious, I went back to the beginning of the article to look for the source, and surprisingly, when I clicked the link of the white paper, the Guide to Understanding Global Temperature Data popped up. Strange. The white paper that the Guardian was rebutting, seems to be the exact same paper that I read a week ago…

The author of the article, Dana Nuccitelli, claimed that the arguments in the guide were an example of a Gish Gallop and therefor too time-consuming to rebut. Therefor he pointed to the Climate Myth database that was compiled by Skeptical Science and in stead of rebutting the arguments in the white paper, he just linked to entries in that database.

So far, so good. Let’s start with how the first argument was rebutted:

1) ‘Carbon dioxide is a trace gas’ is rebutted as Myth #127.

That was odd. I didn’t recognize this being one of the arguments that Spencer used in his guide, yet here the answer on question 1 seems to be reduced to “Carbon dioxide is a trace gas” and was rebutted as such. Meaning as if was being said that CO2 couldn’t have important effects because it is a trace gas in the atmosphere.

That didn’t make much sense. I read several writings from Roy Spencer before (including the guide at issue) and it was not my impression that he thinks that CO2 could not have much effects “because it is a trace gas”. So I went back to the guide and read the arguments of that first question again to see what Spencer actually wrote. By the way, that first question is: “Does an increasing CO2 level mean there will be higher global temperatures?”.

This is where I think is the critique of the Guardian is based on:

The following plot of the CO2 increase at Mauna Loa shows that even though the increase seems substantial in relative terms (left panel), the amount of CO2 in the atmosphere is so small in absolute terms that the change in concentration is not even visible in a plot (right panel) where percent, rather than parts per million, is used for the vertical scale.

spencer guide co2 ppm vs percentage

In fact, most people are surprised to learn that humans have so far contributed only about 1 molecule of CO2 to every 10,000 molecules of air over the last 60 years. About 50 percent of all we emit is absorbed by nature, since CO2 is necessary for photosynthesis and for life to exist on Earth.

Although Spencer showed the percentage of CO2 in the atmosphere, nowhere is being claimed that effects of CO2 is small or insignificant because it is just a trace gas. But of course, one could always interprete his comparison of the increase on ppm level with the percentage in the atmosphere as implicitly making such claim. But that would show that Nuccitelli poorly read the paper.

More telling however is how it was rebutted. Let’s go to Myth 127 at the Skeptical Science website:

sks co2 just trace gas

I could agree that if is being said that human emissions have no impact because they are only a small portion of a trace gas, this would be a logical fallacy. The fact that a substance is a trace element doesn’t say anything about its impacts, even in very small amounts.

Skeptical Science builds its case by giving a whole bunch of analogies with other substances that have strong effects in small doses. Like for example Arsenic that can be poisonous even when it is highly diluted. I can dig that. There are many examples of substances that can have strong effects, even in minute concentrations. So far so good. But analogies go only as far as they go.

They continue with “traces of CO2“, in which they state that percentage of CO2 might be a convenient way to talk about the amount of CO2 in the atmosphere, but it is only relative to the rest of the atmosphere and doesn’t give an absolute amount. Which is more important than the percentage. The more molecules of CO2 in the atmosphere, the more heat it can absorb.

Technically, they are of course right. A percentage doesn’t say anything about the absolute amount in the atmosphere and the more in the atmosphere, the more the potential effect. I can understand that, but it is rather linear view where there is no linearity. First, the effects of CO2 are not linear, but logarithmic. The more CO2 is added, the less the additional effect will be. Second, CO2 works in a complex, coupled and chaotic system. Which will give rise to uncertainties of how the system will react.

Spencer seems not to have a problem with the warming effect of CO2, but rather with the certainty in which it is communicated (emphasis by Roy Spencer):

The science supporting some warming effect of more CO2 in the atmosphere is reasonably sound; what isn’t well known is just how much of a temperature rise will result. This uncertainty is tied up in the holy grail of climate sensitivity, which I will address later.

For the time being, suffice it to say that more CO2 in the atmosphere should cause some warming, but the amount of warming is much more uncertain than the public has been led to believe.

So I am at a loss why Nuccitelli classifies Spencer as having claimed that CO2 is “just a trace gas” and therefor can not have large effects.

The rebuttal was based on a misrepresentation of Spencer’s argument. Spencer did not say that “CO2 could not have a large effect because it was a trace gas”. He did said that some warming was to expected, but that it is not yet known “how much” and that the amount was more uncertain than the public has been led to believe.

Finally, the argument that Nuccitelli uses comes not even close in “rebutting” the alleged argument made by Spencer. Skeptical Science just gives a list of substances that can have large impacts in small amounts. Which is true, but not relevant.

What Spencer tells us is that CO2 is a trace gas and that anthropogenic emissions are only a small addition to it. Then follows that CO2 needs to be a very active substance to have catastrophic consequences in such low concentrations. It is not enough to just prove that some substances can be very active. It is necessarily to prove that CO2 is such a very active substance, that even in these concentrations it has a catastrophic additional impact.

The less can be attributed to anthropogenic emissions, the more potent that substance has to be to have a big impact. It is one thing to prove that trace substances can have a large effect, it is a completely different story to prove that anthropogenic CO2 has a large (additional) effect in the quantities as given by Spencer.


9 thoughts on “Small amounts of very active substances can have large effects, but this doesn’t prove that carbon dioxide is such a substance

  1. chrism56

    You should know by now that anything that Nuccitelli writes is dodgy factoids and just plain untruths. He has plenty of form. The fact that he deems it important to write about Dr Spencer’s article indicates that the consensus is worried about it.
    With regards to trace materials, there are a lot of substances the body needs which can kill you in large doses. Vitamin D and selenium are examples. They are more relevant examples. Or is Mr Nuccitelli advocating a CO2 world?


    1. trustyetverify Post author

      Until shortly I hadn’t read much from Nuccitelli. I knew of course the group he comes from and that gave certain expectations, but I don’t want to dismiss an argument just because of the person who makes it. I like to let the arguments speak. What I have seen until now seems indeed rather dodgy. Nevertheless, there seems to be a devote group of followers who agree with him and apparently don’t notice the issues or at least don’t care about it. I have seen that also in the previous series. That is what I find fascinating.

      The reason why Nuccitelli used the example of trace substances was that he (mis)interpreted Spencer as having claimed that CO2 could not have much effect because it is a trace gas. Therefor Nuccitelli linked to the SkepticalScience article in which examples were given of substances that have a large effect in small doses (for example, Arsenic is deadly in incredibly tiny amounts). Which does prove that trace substances can have a large effect, but doesn’t prove that CO2 is a substance with such a large effect.


  2. chrism56

    You are too kind on Mr Nuccitelli . He deliberately misinterpreted Dr Spenser’s words as well as doing driveby smearing.
    Dr Spenser writes: “So, how can such a minor atmospheric constituent (technically, a “trace gas”) have such a large predicted impact on global temperatures?” and then goes on to explain how it does have some greenhouse effect, the magnitude of which isn’t known. This is twisted to “‘Carbon dioxide is a trace gas’ is rebutted …” And this rebuttal is written by a Sarah who doesn’t ever address whether it is a trace gas or not. In fact, the subject is totally avoided. Wikipedia says about trace gases “A trace gas is a gas which makes up less than 1% by volume of the Earth’s atmosphere, and it includes all gases except nitrogen (78.1%) and oxygen (20.9%)” So Dr Spenser is 100% correct – it is a trace gas.

    Going through the articles other references, they are either previous Guardian articles or SKS articles, both of which he is a significant author to.
    With regards to his previous articles, both Bishop Hill and Climate Audit have taken his comments and Guardian articles apart several times.


    1. trustyetverify Post author

      As far as I could see, the issue is not about “CO2 being a trace gas” (there is no doubt that it is), but about the supposed claim that “because it is a trace gas, it can not have large effects”. The argument has been described as “CO2 is just a trace gas” at the Sks webpage and in the Guardian article. It was also confirmed towards the end of the Guardian article where he repeated this first argument (by the way, it is the reason why there was a picture of Chewbacca on top of the article):

      No scientist should ever claim that carbon pollution is benign because it’s only present in the atmosphere in trace amounts.

      So it was never about being a trace gas, but about the effects it could have being such a gas.

      As you also showed, Spencer never claimed such a thing, he even described the effect in later paragraphs. He only said that it was not certain “how much” the effect is. Which is not unreasonable, knowing that they are talking about a complex, coupled and chaotic system.
      The discrepancy between what Spencer said and how Nuccitelli represented it, was the reason that made me write the post.

      That he “deliberately” misinterpreted Dr Spenser’s words is not something that we can conclude from the article. From what I have read until now, I have no doubt that he is not keen on skeptics, find them utterly stupid and leaves no stone unturned to ridicule them. But deliberately misinterpreting? It is much more plausible that he just very selectively read the arguments, saw the two graphs and jumped to conclusions.


  3. poitsplace

    This is what the entire CAGW camp does. I tend to believe they are actually people that would have been naturally “conservative”, but raised with what now passes for liberalism…taught as dogma. These sorts of people are not thinkers. Everything to them is crystallized knowledge, fixed points that “smarter” people have handed to them, not unlike the way the church operates in many religious groups.

    When presented with a real argument, they fall back to the closest memorized example they have (denier) and spout talking points like a little robot. So you can literally say “I think CO2 is a greenhouse gas and that it will likely cause an amount of warming on the lower end of the values suggested by IPCC scientists”…and they’ll call you a denier because you oppose them on how to “fix” the issue. If you’re not with them, you’re the only other example they’ve been taught, a denier. And they’ve been told that “skeptics” are either false or actually “deniers” if they disagree.

    It’s actually quite interesting when you think about it. These are largely people from cities…cut off from nature. They make those vapid comments about how the world CLEARLY needs to stop using fossil fuels…as they sip water from a disposable plastic bottle. They talk about how terribly we treat animals, as if there’s some magical, candy-land looking place that animals would be in the wild where they never freeze to death, die of thirst, or are still trying to escape as they are literally eaten alive.

    Its the reason the left has so much support in cities…they don’t know how the world actually works…to them things magically show up on store shelves. Heh, it’s the reason educators wrongly assert that people are smarter…oh yes, they’re MUCH better at taking standardized tests for a world where everything fits neatly in it’s own little box…but they’re complete idiots outside of that.

    Meanwhile people in the country (still far more disconnected from reality than they once were) see more of the system…how imperfect things are…how no one-size-fits-all solution will every work as well as some pencil pusher says it will, and how projections of what should or ought to be…often come crashing down with things going in the polar opposite direction.


    1. trustyetverify Post author

      My impression also. It looks like he has a big list with standard answers and when an argument pops up, they look for the answer that is the closest, et voilà … denier argument rebutted …


  4. manicbeancounter

    There are a number of elements to this attack piece, some of which you point out.

    1. He creates prejudice against Dr Spencer. For instance showing his links to alleged disreputable organisations. This is all before the link to Dr Spencer’s article and the links to the supposed counter-arguments. Any neutral reader will either be pre-disposed towards Dana’s arguments or give up in disgust.

    2. Does not answer the actual arguments as it is too time-consuming. Instead he points to counter-arguments.

    3. Apart from a link to Dr Spencer’s original article, there is not one link to counter-arguments.

    4. The Sceptical Science counter-arguments are presented as myth-busting. It implies that the alarmists are on the side of truth and a “sceptic” or “denier” gets everything wrong.

    5. The false claim that Dr Spencer is not part of the 97% consensus. Two examples
    First the Cook et al 2013 paper (where Nuccitelli was a co-author) paper only dealt with declared belief in the broadest, most banal, form of the global warming hypothesis. Roy Spencer acknowledges the greenhouse gas effects
    Second, Doran and Zimmerman 2009 asked two questions.

    (a) When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?
    (b) Do you think human activity is a significant contributing factor in changing mean global temperatures?

    Reading the paper and Spencer would appear to answer “yes” to both. He is only outside of the Consensus in that he does not believe in climate catastrophism, nor in the need for climate mitigation policies. But any survey that asked these questions would not even get a majority in supporting these things.

    The worst part is that there is no encouragement to the reader to compare the different arguments for themselves. The fact that alarmists have to go so far in fabricated arguments and blatant propaganda techniques to discourage any independent thought means is strong circumstantial evidence that they have lost the argument on climate.


  5. trustyetverify Post author


    1. True, that was also something that caught my attention and is the subject of next post.
      Not only neutral readers would be pre-disposed, also the in-group will be strengthened by confirming their position
    2. It is not only time consuming, Spencer brings some nuance to the table and that is not easily translated to a black/white position.
    3. There was only a link to the skeptical science page that debunked … another argument, but yet giving the impression that the arguments are being debunked, while this is not the case
    4. It is a genial strategy that he seemed to have used before: declare the paper a gish gallop and therefor too difficult to tackle, which gives the space to just link to so called myths without tackling them… creating the impression that all these arguments were already debunked thoroughly by the smart in-group and Spencer seemingly clutching at straws. Therefor scoring twice.
    5. That is a very interesting point. It was my intention to use some of those papers and also the claim of Spencer not being in the 97% group as the subject for some next posts, until something else popped up. Maybe later.



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