I had a Twitter conversation yesterday with Jonathan Foley (@GlobalEcoGuy), a climate scientist who directs the Institute on the Environment at the University of Minnesota, that I’d like to follow up on. These aren’t exactly the most focused thoughts I’ve ever had, so bear with me for a bit of a ramble.

I don’t know how to resurrect Twitter threads, but Foley, who’s a good sport, allowed me to pester him about, among other things, what it means to be in the “reasonable middle” on climate change. (He sent me a-pestering with this innocent tweet, which links to his short essay on “becoming a climate pragmatist,” containing good common sense with which I largely agree.) The dispute, as ever, is over “alarmism.” Here’s how Foley describes his message on climate:

I don’t say “it won’t be that bad” — I say that “it won’t be as bad / good as climate hawks / skeptics say”.

This is a very common way of putting things in the climate-o-sphere: “Some people underplay the problem; some people overplay the problem; I play it down the center, just the straight facts. I am not on a side. I am in the reasonable middle.”

I’d note two things about this message.

First, it is true. It is true that climate impacts will be worse than the skeptics say and not as bad as some climate hawks say. It is also true that Foley is honest, non-tribal, and scrupulous about scientific facts when he communicates.

Second, this kind of stance, being in the reasonable center, is extremely attractive to a certain (I’ll never forgive myself for using this word) psychographic, folks I somewhat clumsily call “characterological centrists.” People of a certain temperament will naturally drift to a Goldilocks — not too hot, not too cool — position on matters of political import. They want to be seen as credible, independent brokers of truth, not as activists saying whatever it takes to advance one side or the other.

Now, here’s a different, more “alarmist” message:

Climate change is going to be really, really terrible, and what’s more, it will be far worse than the vast majority of people and institutions with power in the United States believe (or at least act like) it will be.

Two things to note about this message. First, it is also true. Those who wield the most political power in the U.S. do not take climate seriously. The right denies it, the center mouths platitudes but won’t lift a finger, the left gives it lip service, and the fossil-fuel lobby threatens the career anyone who does take it seriously. Obama won’t even mention it on Earth Day. This is not how a political establishment behaves when it acknowledges urgent threats.

And climate change is going to be terrible. Scientists wince when you say it like this because it’s blunt and clunky and simplistic. They want you to specify, you know, probably terrible, in most scenarios, worse in some places than others, and what does “terrible” mean anyway, really, so how about, more precipitation in northern latitudes, well, OK, technically more water in the atmosphere, not necessarily more frequent precipitation, so let’s call it increased frequency of high-volume precipitation events in northern latitudes, and also lower average ice melt with consequent disruption in the volume and timing of longstanding hydrological cycles, and more frequent droughts, especially but not exclusively in southern latitudes, and … zzzzzz.  Nevertheless, given our current trajectory and the bulk of the evidence, overall, we have a pretty damn good idea that climate change is going to suck. The negative impacts will far outweigh the positive impacts. People will suffer.

Second, this sort of stance — the outsider, the agitator, the one who sees through the veil to the heart of a corrupt system and works to expose the lies — is also extremely attractive to a certain psychographic. You know who you are.

So we have two messages, each true, each appealing to a different sort of person. Which should climate communicators use?

Too often, climate types answer this question with some version of, “the one that sounds good to me.” Which is fine if your only goal is to express yourself, or if you’re speaking to other people like you.

But if you’re engaging with the world of politics, power, and public advocacy, your goal is not just to express yourself. It’s to change minds, change behavior, and change policy. And in the pursuit of those goals, it is important to try to be somewhat objective. Matt Yglesias coined the term “pundit’s fallacy” to refer to a political pundit’s belief that the politically savvy thing to do just happens to be what the pundit favors substantively. To that I’d add the “communicator’s fallacy,” which is the advocate’s belief that the most effective message is the one that best fits their own temperament and worldview.

Just because being self-consciously reasonable appeals to you doesn’t mean that reasonable messages work to move the masses. Similarly, just because being self-consciously radical appeals to you doesn’t mean that radical messages work to move the masses. What works can only be discovered through social science and real-world experimentation. There is tons of great work going on around this stuff, but it still sometimes seems like 95 percent of the discussion around messaging/framing/whatever amounts to “this seems like it oughtta work to me.”

My instincts all tell me that a Goldilocks message on climate only serves to soothe and anesthetize. Alarm isn’t enough, it isn’t a complete communications strategy, but surely, in an alarming situation, we must begin with alarm. At least, that seems like it oughtta work to me. But — and I’m sure Foley would agree — our instincts matter less than evidence. So: more evidence, please.