I really wasn't going to do much with this Skeptical Science post by Rob Honeycutt called "Correcting Warren Meyer on Forbes," but several readers have asked me about it and it's Friday and I am sort of bored in the office so here goes. I may skip parts of his critique. That does not necessarily mean I agree with it, but several sections of this article are just so trivial (let's defend Al Gore!) that it is hard to work up any energy about it. As reference, my original article published back in 2012 is here.
Dammit Meyer, You Changed The Words to the Doxology!
The author begins his critique this way:
Mr. Meyer opens with a misleading attempt to frame the issue as a debate on "catastrophic man-man global warming theory." This approach conflates two very distinct elements of the science on anthropogenic climate change. Nowhere in the published scientific literature can you find the phrase he uses. When I did a search on this term in Google Scholar, what did I find? Mr. Meyer's Forbes article. Also searching "catastrophic man-made climate change" I get a smattering of non-research related materials coming from people who rejecting human influence on climate. Meyer has formed a completely irrelevant and fabricated framing of the issue for the basis of his discussion.
In Mr. Meyer's article he claims this is the "core theory" and states that he will use the IPCC as the primary source for this, even though there is no place where the IPCC frames climate change in this manner.
Hey, thanks for making my point! I always start climate discussions by saying that supporters of climate action are frequently sloppy with the way they frame the debate. They use phrases like "climate denier" for folks like me which make no sense, since I don't deny there is a climate. Clearly "climate denier" is a shortcut term for my denying some other more complex proposition, but what proposition exactly? Merely saying "global warming" as a proposition is sloppy because it could include both natural and manmade effects. Climate change is even sloppier (I would argue purposely so) because it obscures the fact that deleterious effects from anthropogenic CO2 must be via the intermediate stage of warming (i.e. there is no theory that CO2 causes hurricanes directly).
With this in mind, I begin nearly every discussion of climate change by doing what many proponents of climate action fail to do -- I am very precise about the proposition I am going to discuss. It's not just global warming, it's man-made global warming. And since the climate alarmists are urging immediate action, it is not just man-made global warming but it is catastrophic man-made global warming, ie man-made global warming with negative effects so severe it requires urgent and extensive actions to circumvent. I think that is a very fair reading of what folks like James Hansen have in mind (if he does not think it will be catastrophic, why is he getting arrested in front of power plants?) The fact that Google searches do not yield these precise terms but rather yield millions of hits for meaningless phrases like "climate denier" just go to support one of the themes of my original piece, that the climate debate is made much muddier by the sloppy framing of the issues in the media.
However, while Mr. Honeycutt criticizes my framing as non-canon, he offers no specific critiques of how the phrase "catastrophic man-made global warming" might be wrong and offers no alternative framing. I really do try to pass Bryan Caplan's ideological Turing test on this stuff, so I am interested -- if advocates for climate action do not think "Catastrophic Man-Made Global Warming" is a fair statement of their theory, what would they use instead?
So Is Feedback a Critical Assumption or Not?
I really don't want to repeat my article, but it is useful to understand my thesis: Catastrophic Man-Made Global Warming Theory is actually a two-part theory, with two chained steps. In the first, CO2 (and methane and other stuff) act as greenhouse gasses and incrementally warm the planet (about 1-1.2C per doubling of CO2 levels). In the second step, via a second theory unrelated to greenhouse gas theory, the initial warming from greenhouse gasses is multiplied several times by positive feedbacks that dominate the Earth's climate system, up to the IPCC's estimate of 3-5 C per doubling. Most of the projected warming in forecasts, such as those from the IPCC, are actually from this second step. My position is that I largely agree with the first step, which is well understood, but believe there is little real understanding of the second, that feedbacks could be net positive or negative, and that scientists either over-estimate their certainty on feedbacks or, more commonly, bury the feedback assumptions and don't even talk about them in public.
As an aside, I have presented this in front of many climate scientists and no one has really disputed that my summary of the logic is correct (they have of course disputed my skepticism with the feedback number). In fact Wikipedia, no climate denier, has this in their article about climate sensitivity:
CO2 climate sensitivity has a component directly due to radiative forcing by CO2, and a further contribution arising from climate feedbacks, both positive and negative. "Without any feedbacks, a doubling of CO2 (which amounts to a forcing of 3.7 W/m2) would result in 1 °C global warming, which is easy to calculate and is undisputed. The remaining uncertainty is due entirely to feedbacks in the system, namely, the water vapor feedback, the ice-albedo feedback, the cloud feedback, and the lapse rate feedback"; addition of these feedbacks leads to a value of the sensitivity to CO2 doubling of approximately 3 °C ± 1.5 °C, which corresponds to a value of λ of 0.8 K/(W/m2).
In a critique, I would expect someone to say, "your description of the theories is wrong because of X" or "I agree with your basic description of the theories but think there are good reasons why we expect feedbacks to be strongly positive". But this is what we get instead from Mr. Honeycutt
New errors pop up when trying to describe this "theory" where he attempts to describe water vapor feedbacks. He states that the IPCC "assumed" a strong positive feedbackfrom water vapor. The IPCC doesn't assume anything. The IPCC is a collection of leading experts in their fields who ware painstakingly cataloguing the scientific research. Meyer also makes an error suggesting the IPCC "just add" 2-4°C onto the 1°C for CO2 warming. Such figures, again, are completely manufactured by Meyer. They don't jibe with climate sensitivity figures and he provides no reference to what he means with figures like these.
The IPCC actually produces graphs such as the following to quantify forcings on the climate system, which also very clearly indicate levels of scientific understanding and uncertainty ranges.
He follows with a IPCC chart that showing forcing number estimates for different atmospheric components and the range of IPCC climate sensitivity forecasts, then says
By comparison, the IPCC and research scientists take the uncertainties involved with climateforcings and feedbacks very seriously. They clearly quantify and document them. The net result of the research suggests that our climate's sensitivity to forcing centers around 3°C for doubling CO2 concentrations. The low end probability is ~1.5°C, and the IPCC clearly state that anything lower than this is highly improbable.
My first thought is a snarky one, that it is interesting to see someone from a site with the word "skeptical" in the title go in for such a full-bore appeal to authority. But to the substance, I am certainly familiar with all the IPCC forcing charts, and what is more, that these charts include a self-assessment by the IPCC about how confident they are in their estimates. Since that self-assessment never is supported by any methodology or analysis in the reports, or any neutral third-party review, I take it with a grain of salt.
But to the rest, if one wants to discuss climate change with a lay audience, it is not wildly useful to start spewing out forcing numbers that have little meaning to the reader, and which the reader has no ability to connect to what they really care about, ie how much temperatures may rise.
More tellingly, though, after I spend most of my article discussing how the media frequently merges the effects of greenhouse gasses acting alone with the effects of feedbacks in the system that multiply or reduce these direct effects, Mr. Honeycutt does just that, offering forcing numbers that, if I read them correctly, include both direct effects and feedback multipliers.
The reason why it is useful to separate the direct warming effect from CO2 from the follow-on effects of feedback multipliers is the level of certainty we have in assessing their values. We can figure out pretty precisely the absorption and reradiation characteristics of CO2 in a laboratory. We can't do anything similar with feedbacks -- they must be inferred using various (all to-date imperfect) approaches to isolating feedback effects from everything else in the climate. An example from another field might be useful. Let's say we want to know the economic effect of hosting the Superbowl in Phoenix. It is pretty easy to measure the direct effects, like the money spent on tickets for the event. But when we look at the total system, things get really hard. Sure we had people come in spending money on the Superbowl, but maybe we had fewer tourists doing other things, or maybe increased spending at the Superbowl was offset by less spending at movies or amusement parks. We might compare that day's revenues to other years, but other years might have had different weather, different population, and a million other small differences that affect the outcome. Sorting through all these literally millions of changing variables to get the net effect of hosting the Superbowl is hard (and in fact for the last Superbowl hosted in Arizona, academic groups have come up with a huge array of numbers that range all the way from highly positive to negative for the net economic effect). The one difference between this example and what scientists have to do to isolate effects of individual inputs to the climate system is that the climate problem is much harder.
In responding to Mr. Honeycutt, I cannot honestly tell if Mr. Honeycutt is refuting this formulation of the problem (ie incremental warming from greenhouse gas effects of CO2 is increased to much higher, catastrophic levels by a second theory that the earth is dominated by strong positive feedbacks) or merely disputing my assertion that the second half of this proposition is not well-proven.
Missing the Point on Past Temperatures
Mr. Honeycutt has a number of problems with my discussion of past temperatures. First, he doesn't like my saying that warming from pre-industrial times was 0.7C. Mea culpa, it was probably 0.8C when I wrote the article. He also does not like the satellite temperature measurement, because it measures temperatures in the lower troposphere (a couple miles up in the atmosphere) rather than at the surface. He is absolutely correct, but you know what? I am skeptical of both land and space data sets. They both have their flaws. Land surface temperatures, especially near the poles and in places like Africa, are widely spaced requiring a lot of interpolation. They are also subject to a number of biases, such as from changing land use and urbanization. Satellite data tends to cover larger swaths of the Earth, but have to be corrected for orbital decay and other satellite aging factors. And as the author mentioned, they measure temperatures in the lower troposphere rather than the surface. However, since the IPCC says that the most warming from greenhouse gasses should be in the lower troposphere, even greater than the warming on the surface, satellites strike me as a useful tool to look for a global warming signal. That is why I always use both. (As an aside, Mr. Honeycutt departs from his appeals to IPCC authority by advocating two land surface data sets NOT chosen by the IPCC as their lead data set -- I use the Hadley CRUT4 because this is what the IPCC uses as their gold standard).
But all this misses the point of why I introduced past temperatures in the first place. My thesis was that past warming was not consistent with high CO2 temperature sensitivity numbers. I used charts in the article but I can repeat the logic simply here. Sensitivity numbers in the IPCC are the warming expected per doubling of CO2 levels. Since pre-industrial times we have increased global CO2 concentrations from about 270ppm (or 0.0270%) to about 405 ppm. This increase of 135pp from 270ppm is conveniently (for the math) about 50% of a doubling. Because the ratio between concentration and temperature is logarithmic, at 50% of a doubling we should see 57% of the doubling effect. So for an IPCC sensitivity of 3C per doubling, since pre-industrial times we should have seen a warming of .57 x 3 = 1.7C. We are nowhere close to this, even if every tenth of degree of warming over the last 100 years was man-made (a proposition with which I would disagree). At the high end of the IPCC range, around 5C, we would have had to see 2.85C of warming to date. At the low end of 1.5C, which the author calls unlikely, we would have seen about 0.86C of historical warming. If one argues that manmade warming is only about half the past warming, then the sensitivity would have to be less than 1C (by the way, this disconnect only gets larger if one considers greenhouse gasses other than CO2).
There are plenty of potential arguments one could counter with. One could argue that time delays are really long or that man-made aerosols are masking past warming -- and we could have a nice back and forth on the topic. Instead we just get printouts from models. Seriously, is that how skeptical folks approach science, accepting black box model output that embodies hundreds or even thousands of potential GIGO assumptions and inputs? I would love someone to show me in a sort of waterfall chart how one gets from 1.7C of expected warming from 270-405ppm to Hadley CRUT4 actual warming around 0.8C. Doesn't anyone feel the need to reconcile their forecasts to actual observations?
There are really good reasons to distrust models. If Donald Trump wanted to invest $100 million in building new military bases, and said that he had a computer model from experts with graphs that show the plan will grow GNP by a trillion dollars, would you automatically accept the model? If GNP only grew by $200 million instead of by a trillion, would you want a reconciliation and explanation?
There are also good reasons to distrust climate models and forecasts. James Hansen's models he used in his famous testimony in front of Congress in 1988 over-predicted warming rates by quite a bit (full explanation here). Since people argue endlessly over this chart about how to center and zero the graphs, it is much easier just to look at implied warming rates:
Even the IPCC finds itself questioning its past warming forecasts:
These forecast failures are not meant as proof the theory is wrong, merely that there is good reason to be skeptical of computer model output as somehow the last word in a debate.
Actually, Missing the Whole Point of the Article
I had naively thought that the title of the article "Understanding the Global Warming Debate" (rather than, say, "Climate Alarmists Are Big Fat Liars") might be a clue I was trying outline the terms of the debate and the skeptic position in it rather than put a detailed dagger through the heart of, say, climate models.
I wrote this article based on my extreme frustration in the climate debate. I have no problem with folks disagreeing with me - in enjoy it. But I was frustrated that the skeptic argument was being mis-portrayed and folks were arguing about the wrong things. Specifically, I was frustrated with both of these two arguments that were frequently thrown in my face:
- "Climate deniers are anti-science morons and liars because they deny the obvious truth of warming from greenhouse gasses like CO2"
In fact, if you read the article, most of the prominent climate skeptics (plus me, as a non-prominent one) totally accept greenhouse gas theory and that CO2, acting alone, would warm the Earth by 1-1.2C. What we are skeptical of is the very net high positive feedbacks (and believe me, for those of you not familiar with dynamic systems analysis, these numbers are very large for stable natural systems) assumed to multiply this initial warming many-fold. Of all the folks I have talked to in the past, perhaps less than 1% were familiar with the fact that warming forecasts were a chain of not one but two theories, both greenhouse gas theory and the theory that the Earth's atmosphere is dominated by strong net positive feedbacks. Even if the audience does not choose to agree with my skepticism over feedback levels, isn't this education of the public about the basic theory useful? The author accuses me of purposeful obfuscation, but for those of us who are skeptical, it is odd that alarmists seem to resist discussing the second part of the theory. Could it be that the evidence for strong positive feedbacks dominating the Earth's long-term-stable greenhouse gas theory is not as strong as that for greenhouse gas theory? Evidence for high atmospheric positive feedbacks simply HAS to be weaker than that for greenhouse gas theory, not only because they have been studied less time but more importantly because it is orders of magnitude harder to parse out values of feedbacks in a complex system than it is to measure the absorption and emission spectrum of a gas in a laboratory.
- "Climate deniers are anti-science morons and liars because there is a 97% consensus behind global warming theory.
Well, studies have shown a 97% agreement on .. something. This comes back to the first part of this post. If one is sloppy about the proposition being tested, then it is easier to get widespread agreement. The original study that arrived at the 97% number asked two questions -- "do you think the world has warmed in the last century" and "do you think a significant part of this warming has been due to man". 97% of scientists said yes. But I, called a climate denier, would have said yes to both as well. Alarmists attempt to shut off debate with skeptics by siting 97% agreement with propositions that have little or nothing to do with skeptics' arguments. Try asking a large group of scientists if they think that the world will warm 3C per doubling of CO2 levels, the proposition with which I disagree, and I guarantee you are not going to get anywhere near 97%. This is simply a bait and switch.
I will conclude with his conclusion:
Meyer ends with an unjustifiable conclusion, stating:
So this is the real problem at the heart of the climate debate — the two sides are debating different propositions! In our chart, proponents of global warming action are vigorously defending the propositions on the left side, propositions with which serious skeptics generally already agree. When skeptics raise issues about climate models, natural sources of warming, and climate feedbacks, advocates of global warming action run back to the left side of the chart and respond that the world is warming and greenhouse gastheory is correct. At best, this is a function of the laziness and scientific illiteracy of the media that allows folks to talk past one another; at worst, it is a purposeful bait-and-switch to avoid debate on the tough issues.
The positions he's put forth in this article are the epitome of lazy analysis and scientific illiteracy. He's bizarrely framed his entire discussion attempting to attack the positions of the IPCC, a body composed of the world's leading researchers, as being scientifically illiterate. One has to ask, from where does his own "literacy" if not from leading climateresearchers? It's certainly not based in the available published research which the IPCC reports are based on.
In this, perhaps he's inadvertently answering his own questions in a manner that he would prefer to reject. What are "skeptics" denying? Answer: The scientific research.
Well, first, I would advise him to work on his reading comprehension scores. I called the media scientifically illiterate, not the IPCC and researchers. The basic framework of greenhouse gas incremental warming multiplied many times by assumed positive net feedbacks is in the scientific literature and the IPCC -- my frustration is that the feedback theory seldom enters the public debate and media articles, despite the fact that the feedback theory is the source of the majority of projected warming and is the heart of many climate skeptic's criticisms of the theory.
And with that, the "skeptical science" article ends with an appeal to authority.
Postscript: Thinking about it more, at some level I find this article weirdly totalitarian, particularly the last paragraph where I am described as doing nothing but polluting the climate discussion. Here he writes:
Forbes is a very high profile publication and thus someone there, at Forbes, decided that it was fine and well to give this person an internet soapbox to promote a position rejecting the climate science which he has absolutely no expertise. He is not genuinely adding to the discussion on climate change but is being placed into a position as someone to listen to. Meyer is polluting the discussion with misinformation and poor analysis which has no bearing on the actual issue of climate change. And thanks to Google, these types of discussions, lacking in any substance, are given equal weight to actual science due to the traffic they generate.
This seems an oddly extreme response to someone who:
- agrees in the linked article that the world has warmed over the last century
- agrees in the linked article that a good chunk of that warming is due to manmade CO2
- agrees in the linked article that CO2 acting as a greenhouse gas will increase temperatures, acting alone, by about 1-1.2C per doubling
- argues for a form of carbon tax (in a different article)
- but disagrees on the magnitude of added warming from net feedback effects.
It seems that we have moved beyond "you are either with us or against us" and entered the realm of "you are either entirely with us on every single detail or you are against us".
Postscript #2: Something else has been bothering me about this critique and I think I can finally put it into words -- the critique is sort of science without thought, a regurgitation of the canon whenever I diverge from orthodoxy without actually considering the arguments presented.
Look, there are tens of thousands of people talking past each other on climate issues. One of the things I try to do, if nothing else to bring something new to the discussion, is try to reframe the discussion in more useful and accesible terms, often with different sorts of graphs. Sometimes these are useful reframings, and sometimes not, but I do know that in general I am a heck of a lot better at creating charts to communicate with a lay audience than is the IPCC or most of the prominent folks on either side of the climate debate. This is why getting feedback (as in this critique) that I use different words to summarize the issue or that I do not use the standard charts everyone else xeroxes out of the IPCC reports (as did Mr. Honeycutt) is not very helpful.