Karl Smith, who is very smart, is still stunningly dense on climate change:

One of the core ideas behind climate change is that if humans continue to burn fossil fuels then the earth will become warmer.

As it stands there are some places on earth that are so hot that no one wants to live there. There are also some places that are so cold that no one wants to live.

A baseline guesstimate might be that if the earth got warmer then the number of places that were too hot would expand and the number of places that were too cold would contract.

A possible strategy then would be for humans to move from the places that are newly too hot to the places that were formerly too cold.

Now this may very well be a horrible idea. In which case I would expect someone to say: I hear were you are coming from Karl but . . . . and that’s why that plan won’t work.

I’ve received a lot of email and tweets on this issue. I have tried to go through them all. So far I haven’t seen one that comes at it like that. Lots of folks mocked me. Some were kind enough to send along information on exactly how hot the too hot places might get and what the consequences of excess heat might be.

Yet, so far, nothing addressing why moving to cooler places won’t work.

Again, even if we are certain this won’t work its probably worth stepping through exactly why it won’t work. At least so everyone can be on the same page.

This is remarkably foolish. Just taking this at face value, you are just sacrificing an enormous amount of non-tradable capital by abandoning cities that would be in the too-hot category. People like Miami and Eilat and Quito and Nairobi and Jakarta and La Paz and Mexico City and all kinds of other places that could become overheated. We would lose a lot of built infrastructure, history, culture, and unique clusters of human interactions that way. Plus, if millions or billions of people are forced to evacuate their homes due to something that was preventable and not of their doing, that’s not very nice.

But this also radically understates what global warming really is. If all it did was “raise the temperature of every place on earth by X degrees” then I would just move to Boston or Montreal and call it a day. But it also, for example, melts the polar ice caps. Which could leave some of those formerly-cold-and-now-warm cities underwater since a lot of them are coastal. It could massively impact food supplies, leading to shortages which lead to starvation. It could cause hurricanes, tornadoes, and other dangerous weather systems to become more common and more extreme. It could make wet places dry and dry places wet, leading to flooding or fires. It could cause mass extinctions of species.

And most importantly, once you get into these kinds of scenarios, the simulations start to get haywire. Kind of like the scene from Sunshine (which tragically seems not be on YouTube) when Capa shows how projections of the bomb’s impact scramble the simulator past a certain point. This is what Matt Yglesias tried to say to Smith in a nice way about “tail risk” – is that it’s very possible that global warming could cause chain reactions of awfulness whose outcomes we cannot possibly predict. It’s the kind of thing economists have trouble pricing, sure, but it’s easier to price it when you acknowledge it. We’re not talking about just relocating vacation homes here.

I mean, seriously, dude, before you piss off the whole internets, at least read this first.