Subtle Truths, 2: Global Warming
“The truth is rarely pure and never simple.” --Oscar Wilde
The insane extremists are winning the debate about global warming. Whatever your view of global warming, you probably agree with me about that. You probably also think the crazy extremists are the people on the opposite side from yourself – the people on the left if you’re on the right, or the people on the right if you’re on the left.
What I’ve realized is that both the left and the right are dominated by crazy extremists who ignore facts and evidence so they can believe what they want to believe. I didn’t really appreciate this until recently. The way I came to appreciate it is that I taught a class on social & political philosophy. For the last unit, I had students select the topics. Global warming turned out to be a favorite topic, so I prepared a lecture about that, after which we discussed the issue on Zoom. Here is the lecture, posted on YouTube:
(It was an online lecture, due to the pandemic.)
I gave as evenhanded a presentation as I could. I included the views of Bjorn Lomborg, as one of the reasonable people who talks about climate change. (Here is his TED talk, in case you haven’t seen him yet: https://www.youtube.com/watch?v=Dtbn9zBfJSs.)
Lomborg’s project is to prioritize solutions to global problems using cost-benefit analysis. He finds that climate change mitigation is a very low priority in those terms – if you had 50 billion dollars to spend, you wouldn’t spend any of it on reducing climate change; you’d instead spend it on stuff like micronutrient supplementation, fighting malaria, vaccines, deworming, etc. That’s because the plans we have for climate mitigation are incredibly expensive and would only produce a tiny impact on global warming, a long time in the future. Micronutrient supplementation, by contrast, produces a big benefit, immediately, for little cost.
Some of the students could not see Lomborg’s perspective. If we all die, what good will it be to have decreased the spread of malaria?
That’s not an exaggeration; that’s what they thought. They presupposed that climate change is going to literally end the human species if we don’t swiftly stop it. I think they thought that this was common knowledge. I had told them that the U.N. projection was for an excess 500,000 deaths per year, worldwide, by mid-century, as a result of climate change. (That will be out of a total death rate of about 90 million per year.) But this information didn’t seem to have modified people’s estimate of the probability of literally everyone dying.
Btw, a recent study estimates that climate change, if not curtailed, may cost the world 7.2% of GDP in the year 2100 (https://www.washingtonpost.com/weather/2019/08/19/climate-change-could-cost-us-up-percent-its-gdp-by-study-finds/). This, while serious, does not quite sound like a world-ending catastrophe.
This semester, we didn’t cover global warming as it wasn’t one of the top student-suggested topics. But some students injected it into other conversations. I think some of these students quickly acquired the belief that I must be some sort of climate denialist, since I don’t think the world is coming to an end.
I think this is because the popular “climate change” discourse has become dominated by two extremist views that both ignore the evidence:
Extremist view #1: It’s not happening at all, or if it is, human activity has nothing to do with it. It’s a giant hoax, or the mainstream climate scientists don’t know what they’re doing, and the good scientists are afraid to speak out against it due to persecution by the ideological climate-change proponents.
Extremist view #2: Oh my god, we’re all going to die!!! Here is AOC in 2019, predicting the end of the world in 12 years: https://twitter.com/People4Bernie/status/1087443780565782528. Someone is going to have egg on her face in 2031. I assume most climate alarmists would not predict the end to be so soon, but I think there really are a significant number of people who think the end is approaching.
Those are both unreasonable positions. You shouldn't think either of those things.
So here is what I think is reasonable to think about global warming. I’m not a climate expert, or any other relevant kind of expert; this is just what a reasonable lay person thinks:
1. The Earth seems to be getting warmer. My evidence for this: Lots of experts think this, and, given my general background knowledge, this is the sort of thing that it is extremely plausible that the experts would know about. (It’s not some inaccessible fact like what happened before the Big Bang.)
2. Human activity is probably contributing some significant amount to that effect. My evidence for this: See above, but with somewhat less confidence this time, since figuring out the cause of a temperature rise would probably be harder than simply detecting the temperature rise.
Objection: Michael Crichton, the novelist and climate skeptic, says that one does not rely on ‘consensus’ in science. In real science, one only looks at the objective data. He also notes numerous occasions on which the consensus view among scientists was false. (https://stephenschneider.stanford.edu/Publications/PDF_Papers/Crichton2003.pdf. This is actually a very interesting essay.)
Reply: (a) It is true that, if you are a scientist, you should make your assessment based on the objective data, not other people’s opinions. But if you are a lay person, you should listen to the judgments of the scientists, since they are probably better than you are at assessing the evidence. (b) The possibility of scientists making an error does not mean that non-scientists are better at assessing scientific data. (I can’t believe how often I have to keep pointing that out.) However unreliable smart people are, dumb people are worse. However unreliable experts are, you should assume that amateurs are even worse.
3. Climate change will impose significant but non-catastrophic costs on humanity in the next several decades. I’ve mentioned a couple of expert estimates of the costs above. I’m not assuming that any of the estimates are going to be highly accurate; hence the vagueness of my “prediction”. Maybe the actual costs will be five times what people are expecting, or a fifth what they’re expecting, etc. But no serious expert estimates 8 billion deaths from climate change, or a 100% decline in GDP, or anything remotely like that.
Moreover, I think this is a case in which you could use some common sense. People are projecting a temperature increases of between 1.5 and 5 degrees C by 2100. Are we supposed to think that the world is going to end if it gets 5 degrees hotter on average? What if the place you live got 5 degrees hotter: would you keel over?
I know, the coastal cities are supposed to get flooded. I don’t even think that’s going to happen. Climate scientists might be able to predict a rise in sea levels. They can’t predict, however, that any cities are going to be flooded. (I think this is a point of unclarity among environmentalists.) Why not? If the sea level rises to above the elevation of a city, doesn’t it logically follow that the city will be flooded? No. Many cities are already below sea level yet are not underwater. Copenhagen is about 0 feet above sea level, with some parts of it 3 feet below sea level. Amsterdam is about 12 feet below sea level. New Orleans is 1-2 feet below sea level. Etc. People have found ways of preventing those cities from being flooded.
More generally, people adapt to their environment. Any prediction of costs of warming has to take into account what people are going to do to adapt – not just assume that we’re going to sit here stupidly. For another example, if some farmlands become too hot to grow crops efficiently, that doesn’t mean we’ll just starve. We’ll move our crops elsewhere (some places that are presently too cold for agriculture will cease to be too cold). Again, all of this entails significant costs. But it doesn’t entail the end of the world.
By the way, since this is going to be happening decades in the future, you should assume that it’s going to be much easier for humans to adapt to those changes than it would be today, because the people of the future are going to be much wealthier, and are going to have much more advanced technology, than us.
Imagine someone in the year 1921 trying to plan for the year 2021. That person would have had no idea of all the amazing technologies and the vast wealth that we would have today. (Ex.: He would have had no idea what a ‘computer’ was, or a cell phone, or the internet. He wouldn’t have heard of nuclear power, or rockets, or satellites. He would think of horses and trains as the major means of transportation. Etc.) As a result, he’d have vastly underestimated our ability to adapt to global problems.
Similarly, we probably have no idea what technologies people are going to have in 2100, or how people will be living, but it'll probably be vastly better than today.
4. Bjorn Lomborg is probably right. If we have unlimited money, sure, we should fix global warming. But if we have limited funds, we have to prioritize.
Lomborg’s view is not just his personal opinion. It’s the outcome of the Copenhagen Consensus project. He gathers together leading economists, gives them assessments from experts on various plans for addressing different global problems, and has them apply cost-benefit analysis to the plans. The economists then rank the plans in terms of cost-effectiveness. This is all based on what subject-matter experts estimate to be the costs and the effects of the best plans that people have come up with for addressing global problems (including climate change and many other problems).
So, just as you should generally defer to the scientific consensus on climate change, you should also generally defer to the Copenhagen consensus.
Lomborg, however, is pro-carbon-tax. This is a reasonable measure, because releasing CO2 into the atmosphere imposes negative externalities. In libertarian terms, it’s a form of (very small) aggression against the rest of the world, which a person could justly be required to compensate for. Of course, the same applies to all other pollution, including, e.g., the methane that is released by animal agriculture, which is another major contributor to global warming.
Why not ban all greenhouse gas release? Because that would shut down modern civilization, and hundreds of millions more would die. A moderate pollution tax deters frivolous production, while allowing the pollution that would be the most difficult and costly to avert to continue.