When I started this blog, I wanted it to be entirely about science and the fundamental concepts of logic. As such, I decided that topics like religion and politics where off limits. However, anytime that a politician makes a statement about science, they enter my territory and I feel obliged to deal with their comments (by the same token, I only talk about religion when people use it to make claims about science). One of the most common and irritating ways that this occurs is when politicians try to compare modern science (usually climate research) to the idea that the earth is flat and/or we are the center of the universe. This argument is used ad nauseum and I have dealt with it before. Nevertheless, it is once again featuring prominently in our political dialogue, so I feel the need to explain why it is utter nonsense yet again.
I am, of course, referring to the recent comments by Trump advisor Anthony Scaramucci on CNN. When asked about the scientific consensus on climate change, he made several hopelessly ignorant comments like, “There was an overwhelming science that the Earth was flat, and there was an overwhelming science that we were the center of the world.” Statements like that are, however, absurd for numerous reasons.
First, and most obviously, they are blatantly false. Science is an extremely careful, empirical, and systematic process of making observations, forming hypotheses, and empirically testing those hypotheses by using repeatable, controlled* experiments, and that system is an extremely recent one. It has only existed in its modern form for the last few centuries. In contrast, we have known that the earth was round since the ancient Greeks! So there can’t possibly have been a scientific consensus that the earth was flat because science as we know it did not even exist then! Similarly, the idea that we are the center of the universe was discredited long before modern science, and the idea was largely based on religion. Indeed, although Galileo slightly predates modern science, when he demonstrated that the earth was not the center of the universe, he did so by applying the same basic type of systematic observations and reasoning that scientists use today. Thus, although modern science never said that the earth was the center of the universe, scientific reasoning was the thing that discredited that idea.
I want to elaborate on that last point for a second, because I want to be clear that I am not suggesting that there were no scientists before the modern era. There certainly were, but science was not the formalized discipline that it is now. In other words, although there were people who were making observations, testing hypotheses, etc., there was not a standard for the type of reasoning that qualified as science, nor was there the vast body of philosophical thought about the nature of science that we have today. My point is that the “science” that said that the earth is flat and the earth is the center of the universe is not actually the same thing that we know as science today, thus the comparison is invalid (i.e., it is an equivocation fallacy because it uses the word “science” to mean two different things).
Further, so far I have only been talking about the general concept of what science is, but we also have to take into account the tools that are available to scientists. For example, the statistics and mathematical formulas that we use today have only been around for about 100 years (sometimes much less than that). Those mathematics are extremely important because they are what allow us to rigorously examine our data and assign confidence values to our results. Similarly, today we can use computers to analyze millions of data points, run massive simulations, and do analyses that were unimaginable to scientists just a few decades ago. Further, our ability to accurately make the measurements that we use in those analyses has also increased astronomically. For example, we now have satellites that can continuously collect very precise data from all of the world. Tools like that give us incredible power for understanding our planet and the universe in general, and they give modern science a major advantage over past scientific endeavors.
There is also another problem here, and it is a more fundamental one. If this argument actually worked, then you could use it any time that you wanted, rather than simply for climate change. In other words, if the fact that people used to think that the earth was flat actually gave you carte blanche to reject science, then you would never have to accept any scientific result that you didn’t like. For example, I could say, “scientists say that washing your hands helps prevent the spread of disease, but they were wrong about the earth being flat, so I don’t have to listen to them when they say that we should wash our hands.” That is obviously absurd, but that is exactly the same thing that Scaramucci did. His argument was logically identical, which means that if either of those arguments worked, then both should work, and the fact that the hand washing example is clearly absurd means that the climate change argument must also be absurd. That’s how logic works.
Nevertheless, you might be tempted to think, “but scientists aren’t completely, 100% sure that we are causing climate change, so it is always possible that they are wrong.” Technically, that is true, but here is the important qualifier: science never gives us 100% certainty. It is inherently a skeptical process, and it only tells us what is most likely true given the current evidence, not what is absolutely true (details here). So sure, it is true that I can’t be 100% sure that we are causing climate change, but I also can’t 100% sure that the earth is round. Indeed, I can’t be 100% sure that you even exist, nor can I be 100% sure that Donald Trump isn’t an alien squid from another universe. However, the fact that I can’t be 100% sure about those things does not mean that I get to have any form of practical doubt about them. It would clearly be ridiculous for me to actually think that Trump is an alien squid, and politicians should not make laws based on that notion. Even so, the fact that we can’t be 100% sure about climate change does not mean that you get to have any practical doubt about it, nor should we be basing laws on that doubt.
In technical terms, what I have been describing is known as an argument from ignorance fallacy. It can occur in many ways, but one of its forms happens when you say, “we can’t be sure that X is true, therefore X is false” or “we can’t be sure that X is true, therefore it is reasonable to believe that it isn’t true.” This is not logically valid. The fact that we can’t be completely certain of a conclusion does not mean that you can assume that all of the evidence supporting that conclusion is false. This comes back to one of my favorite topics: the burden of proof. The person making a claim is always responsible for providing the evidence to support that claim. In other words, if you want to claim that we aren’t causing climate change, then you must provide actual evidence that we aren’t. You can’t simply assert that we can’t be 100% certain, the models might be wrong, etc. If you want to claim that all of the scientific evidence is wrong, then you have to provide evidence to support that claim, not speculations. Further, although it is true that science never proves anything with 100% certainty, there are some topics that are so well supported by so many lines of evidence that it is almost unthinkable that they could actually be totally wrong, and anthropogenic climate change is one of those topics (others include atomic theory, the germ theory of diseases, etc.).
This brings me to the final topic that I want to discuss here: the actual evidence for climate change. You see, so far I have been talking in pretty general terms about science, but Scaramucci’s statements are particularly absurd and misguided when we focus in on climate change, because there is so much evidence supporting it. As I have explained in more detail elsewhere, we have tested the sun, volcanoes, and other natural drivers of climate change, and they can’t explain the current warming by themselves (Meehl, et al. 2004; Hansen et al. 2005; Wild et al. 2007; Lockwood and Frohlich 2007, 2008; Lean and Rind 2008; Foster and Rahmstorf 2011; Imbers et al. 2014). However, including our greenhouse gases in the calculations does explain the warming trend (Stott et al. 2001; Meehl et al. 2004; Allen et al. 2006; Lean and Rind 2008; Imbers et al. 2014). In other words, we know that our emissions are driving the warming, because we have tested the natural drivers of climate change, and none of them (even when combined) can account for the current increase in temperatures. Further, we know that CO2 traps heat and is largely responsible for both our climate and past climate changes (Lorius et al. 1990; Tripati et al. 2009; Shakun et al. 2012), we know that we have greatly increased the CO2 in the atmosphere (Bohm et al. 2002; Ghosh and Brand 2003;Wei et al. 2009), and we have used satellites to directly measure the amount of heat energy that CO2 in our atmosphere is trapping, and (just as expected) it is trapping an increasing amount of heat (Harries et al. 2001; Griggs and Harries 2007). In other words, we have direct evidence that our CO2 is causing the earth to trap more heat (i.e., warm). The evidence is overwhelming, and when you look at the scientific literature, you will find thousands of papers saying that we are causing climate change, and only a tiny handful that disagree. The scientific consensus on this topic is incredible (details here), and the consensus among scientists exists because of the evidence. Scientists do not “believe” in climate change (as Scaramucci erroneously asserts), rather we accept it as fact because of the overwhelming evidence. There is simply no serious debate on this topic among actual scientists.
To illustrate this a different way, a few weeks ago, I attended the annual meeting of the Ecological Society of Australia, and there were lots of talks about the effects that climate change is having and will have on plants and animals, but not one of those talks hedged their comments with statements like, “if climate change is real.” Rather, all of them treated anthropogenic climate change as a scientific fact because that is what it is, and it is absolutely crazy to suggest that we should act as if it isn’t settled just because some non-scientists over 2000 years ago thought that the earth was flat! Further, the fact that a handful of scientists today disagree doesn’t help that argument either because there will always be a few who disagree on any topic (this is an appeal to authority fallacy). Having an advanced degree does not guarantee that you know what you are talking about, and you can sadly find plenty of crackpots even among scientists (note: before you accuse me of committing an appeal to authority fallacy by citing the consensus, please read this post on the difference between appealing to authority and deferring to experts).
To be clear, there is disagreement about the extent of climate change that we are going to cause. There are lots of variables that have to be considered, and there are admittedly still topics that we are actively studying in order to refine out models. However, although the models may be imprecise about the extent of the warming, it is almost unthinkable that we are wrong about the warming itself. Indeed, the idea that we are causing the climate to change is not based on the predictive models, rather it is based on research like the papers I presented earlier. Further, out models have actually done a pretty good job of predicting the current warming, so although they aren’t perfect, they probably aren’t that far off (Hansen et al. 2006; Frame and Stone 2012; Rahmstorf et al. 2012; Cowtan et al. 2015; Marotzke and Firster 2015).
In short, the science that said that the earth is flat or that we are the center of the universe was not the same thing as what we know as science today. Further, the past few decades have furnished us with a fantastic array of amazing tools for collecting and analyzing massive amounts of data, and when we apply those tools to the topic of climate change, we get an extremely consistent result: it is real and we are the main cause of it. Because of that evidence, there is no serious debate about this among scientists. Yes, there are a few dissenting voices, but those will always be there. Further, yes, it is always technically possible that we are wrong, but it is also technically possible that Donald Trump is a space squid, and the fact that something is technically possible does not mean that it is rational to think that it is actually true.
*Note: When I said that science uses controlled experiments, I was not referring specifically to randomized controlled trials (RCTs). Although they are a particularly powerful design, they are far from the only one, and they often aren’t applicable in fields outside of medicine. In climate research, for example, we generally can’t do RCTs, but we can still control our experiments and analyses by measuring all of the confounding factors and including those factors in out analyses.
- “But scientists have been wrong in the past…”
- Settled science part 1: Is science ever actually settled?
- Settled science part 2: Creating the illusion of a debate
- 25 myths and bad arguments about climate change
- Basics of Global Climate Change: A Logical Proof That it is Our Fault
- Debunking 25 arguments against climate change in 5 sentences or less (each)
- Global warming hasn’t paused
- Global warming isn’t natural, and here’s how we know
- The GHCN Temperature Adjustment Myth
- Yes, there is a strong consensus on climate change
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