In the documentary “Before the Flood” there were several scenes that stood out like a sore thumb. One of them was a scene in which Michael Mann claimed:
There is about as much as robust a consensus human caused climate change than there is for any matter in science, be it the theory of gravity. 97% of climate scientists agree that the globe is warming. Our climate is changing and it is due to fossil fuel burning and other human activities. Unfortunately we are fighting this massive disinformation campaign to confuse the public.
The comparison between human caused climate change as a robust consensuses like gravity was quite puzzling. So I searched the internet for what he could mean by this claim. I ended up with the recent article “We can’t afford to wait”, in which he and Kim Kasting explain their gravity example and what it means for climate science. This is how they explain it, apparently as a reaction to a column of a Jonah Goldberg on settled science (my emphasis on the most important parts to understand the reasoning):
What Goldberg fails to understand is that the corpus of scientific knowledge consists of matters that are “settled” and matters that are not. None of us question the theory of gravity. The fact that it causes unsupported objects to fall in Earth’s near-surface environment has been settled back to the time of Isaac Newton, if not earlier. (Newton merely explained why they fall.) Yet, wide open questions still remain. For example, scientists have yet to reconcile Einstein’s theory of general relativity (our most general theory about gravity) with quantum mechanics (our most general theory about the nature of matter). The fact that there are still open questions about the theory of gravity doesn’t make it safe to jump off a cliff.
Yet that is essentially what Goldberg is asking us to do when it comes to human-caused climate change. Certain aspects of climate science – e.g. the existence of the greenhouse effect, the fact that Earth is warming, and that we cannot explain that warming in terms of natural factors – are indeed “settled,” by any reasonable definition of the word. They are no longer actively debated by mainstream climate scientists. Other factors, such as the precise amount of warming we can expect, the subtle role of changes in clouds, and how things like tornadoes might be impacted, still are. But when it comes to making national and international policy, we cannot afford to wait for every aspect of the science to be completely settled. Much as the only way to confirm the danger of jumping off a cliff is to see what happens when you hit the bottom, waiting 50 years to see how much warming results from the continued burning of fossil fuels will likely commit us to the most severe consequences of climate change.
Basically, they build their argument on:
- the existence of the greenhouse gas effect
- the fact that it is warming
- and that this warming cannot be explained in terms of natural factors.
The last two are meaningless. It is not the warming that is in dispute, it is the cause of the warming. That we can’t explain the warming in terms of natural factors is no wonder, knowing that investigators are still looking into natural factors. Since when is negative proof a valid argument?
However the first one, the existence of greenhouse effect, made me understand what he is trying to claim with the analogy. Similar to Newton’s formula (which was already proposed in the 17th century), there is the Arrhenius’ formula to calculate the greenhouse effect (from the 19th century). So both were established for quite a while already.
With the formula of Newton, we can calculate the acceleration of a falling object from a certain height, how long it will take until it hits the ground, how fast it is going at impact, and so on. With the Arrhenius formula is easy to calculate the effect of CO2 levels on temperature.
Looking at it that way, the analogy makes perfect sense: when we start emitting extra CO2 in the atmosphere, the temperatures will go up, whether or not there are still things that we don’t understand yet.
So far, so good.
But analogies are great as far as they go, but only go so far. There is an important difference between the two. While the Newton formula is applicable to all objects that fall in Earth’s near-surface environment, the Arrhenius formula calculates the greenhouse effect of CO2 in isolation of other effects. CO2 isn’t the only thing that influences temperature. We live in a complex, coupled, chaotic system and there are many other (combinations of) parameters that define the outcome. That is where the analogy fails.
I have no problem believing that there is a consensus on gravity, that we can calculate a lot of stuff with the Newton formula, but the calculation of greenhouse effect of CO2 is only a part of the equation.
The issue is how much the influence is of the addition of our CO2 emissions on temperature as compared to the CO2 from natural sources in the real world. I don’t think that this is settled yet, even when applying the Arrhenius formula.
The analogy only stands on the certainty that these additional human emissions are the key driver or at least an important driver of climate change. How certain can we be about that? This brings us to the second claim which is about the 97% consensus.
I have no problem with his statement that “97% of the scientists agree that the globe is warming”. That is not controversial at all. As far as I seen the graphs of the different data sets, there was an increase in temperatures since the beginning of the measurements in 1850-1880, so I am a bit surprised that there is no 100% agreement on this fact.
The statement “97% of the climate scientists” is interesting. This means that Mann is not talking about the Cook survey (Cook counted scientific papers, not scientists and he also didn’t focus on “climate scientists”). It also couldn’t be the Anderegg study either (Anderegg et al came to a total of 66% of climate researchers who where “convinced by the evidence for anthropogenic climate change”, not 97% → they came to their 97-number by looking at the percentages of publications of the convinced group). This leaves us with the Doran & Zimmerman survey which found a 97.4% consensus by climate scientists that the current global mean temperatures had risen since pre-1800 levels. Which confirms the claim that Michael Mann made in the movie, but at such the statement is utterly meaningless. The movie is about the (catastrophic) effects of this warming on climate and there is no consensus about that.
Now look very carefully how the pea got switched. The next statement is: “Our climate is changing and it is due to fossil fuel burning and other human activities”. In fact, this has nothing to do with the previous (correct) statement, yet now it is been framed as if those 97% also agreed with that (they didn’t, they just agreed that the globe got warmer and that humans have some influence). That is inflating the consensus to something it isn’t.
In the final sentence we learn that there is some massive disinformation campaign to confuse the public. It is not clear whether this is related to the part of climate changing because of emission (remember the pea that has been switched) or whether it is related to the part of the 97% consensus. No matter which part it is related to, I don’t buy it.
Just look at how the consensus is brought in this movie. The consensus position they referred to is rather neutral, while in the movie they use it to prove that action is needed (meaning that climate change is dangerous). This is not what there is a consensus about.
Or just look at how the consensus is misrepresented by the media, also by some scientists. For example John Cook made a claim about the consensus that was unsupported by the evidence, despite being an author of two papers on consensus and therefor should know better…
The same Cook also has a history of misrepresenting his own research on the 97% consensus, especially when explaining the paper to the public (for example here and here).
Then of course there are the many non-scientific sources that are copying this misrepresentations or even making variations on the theme. For example the famous “97 percent of scientists agree: climate change is real, man-made and dangerous”-tweet from the Obama twitter account, which was not support by the scientific paper he linked to. Such misrepresentations about the 97% consensus are widespread on the internet and in the media.
If it would be really true that there is a massive disinformation campaign coming from skeptics, then their message is not exactly showing much and they will have to step it up a notch. Looking back at my believer’s years, I can’t remember campaigns from skeptics, let alone massive ones. The mainstream media hardly brings the messages from skeptics. Even in the case skeptical arguments are presented in the media, these were in fact brought by … the alarmists themselves, spinning those arguments in any direction they wanted without any feedback. Even now, when I found myself on the other side, I notice that the skeptical message is still hard to find when one doesn’t know where to look.
I find the idea of a “massive” disinformation campaign, somehow organized by skeptics, completely and utterly ridiculous. From my personal experience at both sides of the debate, I would even argue that this “massive” disinformation campaign is in fact coming from the alarmist side.