I’ll take a swing at that.

You probably know that actor Leonardo DiCaprio is a climate activist, and he is trying to persuade the world that climate change is both real and serious. Someone asked me on Twitter what it would take for DiCaprio (for example) to persuade a person like me.
I’ll take a swing at that.

Mister Whiskers and Mister Biggles

For starters, you must separate the questions of real and serious. The real part refers to the climate models. The serious part refers to economic models. Those are different topics.
If you want to convince me that climate change is real, the best approach is to abandon the current method that packages climate models in a fashion that is identical to well-known scams. (Or hoaxes, if you prefer.)
Let me say this doubly-clear. When I say climate models are packaged in a fashion that is identical to known scams, I am not saying they are scams. I’m saying they are packaged to look exactly like scams. There is no hope for credibility with that communication plan.
To make my point visual, imagine walking into your kitchen and finding an intruder wearing a ski mask and holding a gun. You assume this person is not your friendly neighbor because he is packaged exactly like an armed burglar. If you shoot that intruder, and it turns out to be your neighbor playing a prank, you probably won’t go to jail because it isn’t your fault. The problem was that your neighbor packaged himself to look exactly like an armed burglar.
Climate scientists tell us that there are hundreds of climate models, all somewhat different. I assume that most of them do a good job predicting the past (hindcasting) because otherwise they would not be models at all. Hindcasting is one minimum requirement for being a model in this field, I would assume.
Then science ignores the models that are too far off from observed temperatures as we proceed into the future and check the predictions against reality. Sometimes scientists also “tune” the models to hindcast better, meaning tweaking assumptions. As a non-scientists, I can’t judge whether or not the tuning and tweaking are valid from a scientific perspective. But I can judge that this pattern is identical to known scams. I described the known scams in this post.
And to my skeptical mind, it sounds fishy that there are dozens or more different climate models that are getting tuned to match observations. That doesn’t sound credible, even if it is logically and scientifically sound. I am not qualified to judge the logic or science. But I am left wondering why it has to sound exactly like a hoax if it isn’t one. Was there not a credible-sounding way to make the case?
Personally, I would find it compelling if science settled on one climate model (not dozens) and reported that it was accurate (enough), based on temperature observations, for the next five years. If they pull that off, they have my attention. But they will never convince me with multiple models. That just isn’t possible.
If climate scientists want their climate predictions to be believed, they need to vote on the best model, and stick with it for a few years. If they can’t do that, all I will see is lots of blind squirrels in a field of nuts. Some squirrels will accidentally find some nuts. But it won’t look like science to me because of the way it is packaged.
I do realize that picking one model as the “best” is not something science can do with comfort. It would feel dishonest, I assume, since they don’t know which one will perform best. But if science wants to be persuasive, they need to pick one model. And it needs to be accurate(ish) for the next five years. Nothing else would be persuasive to me.
On the second point, about how serious the alleged problem of climate change is, we have to rely not on scientists but on economists. And economists have zero credibility for long-term forecasts of that type. So the serious part is beyond the reach of persuasion. You can’t get there from here because economic models are no more credible than astrology.
By the way, my educational background is in economics and business. And for years, my corporate jobs involved making complex financial projections about budgets. In other words, I was perpetuating financial fraud within the company, by order of my boss. He told me to pretend my financial projections were real, and I did. But they were not real. My predictions were in line with whatever my boss told me they would be. I “tuned” my assumptions until I got my boss’s answer.
When I tell you it would be hard to convince me that a stranger’s economic model is credible, keep my experience in mind. I’ve seen lots of economic models. I’ve built economic models. In my experience, they are nothing but guesses, bias, and outright fraud.
The only way to convince me that climate change is bad for the economy is to wait until it starts breaking things. If I see it, and scientists agree I am seeing it, I might believe it. But long-term economic predictions can’t get me there.
I remind you that my topic is about persuasion, not the underlying truth of climate change. I don’t have access to the underlying truth because I am not a scientist working in the field. My information comes from strangers that tell me their interpretation of what the scientists are saying. I am as far from science as you can get.
The people who are hallucinating the hardest on this topic are the non-scientists who believe they have done a deep dive into the scientific papers and the climate models and arrived at a rational conclusion. The illusion here is that getting information from other humans is the same as “science.”
Another group of hallucinators believe that they can determine the scientific truth of climate change by counting the number of scientists on each side. But that ignores the fact that science often has the majority on the wrong side. That happens every time a new idea is starting to replace an old one. Darwin did not agree with the consensus when he introduced evolution. Einstein’s ideas were slow to catch on, etc.
When the majority of scientists are on one side, what matters most is the flow rate from one side to the other, not the raw numbers. I need to know which direction the scientists are moving. Are more climate scientists moving toward climate skepticism or away from it? Give me that data and I’ll have something useful. But counting the number on each side during one slice of time is meaningless for persuasion.
My point is that Leonardo DiCaprio would have a tough time persuading me that climate science is both real and serious. But it isn’t his fault, because science has packaged climate science to look like a hoax, and sent him out to sell it. I respect and admire DiCaprio for his heart on this matter, and his effort on behalf of the planet. But science has failed him by giving him hoax-looking sales collateral.