I just got an email asking me to sign on to an open letter arguing for some carbon tax policies. I’m seeing some push back from (smart, economically literate) Facebook friends, but I think it’s a viable step in the right direction.

Here’s the statement paraphrased:

We think global warming is an important and urgent issue and we recommend these five things:

1. A carbon tax is the best, most cost-efficient way to do as much about carbon as needs to be done. [For a given level of carbon reduction, I agree. How much carbon reduction should happen (and how much at government behest) I am deeply agnostic about.]

2. We think this should be phased in over time and should be revenue neutral. [Yes on both points, but the rest of the statement makes it seem like they’re talking about a pretty short time horizon. I’m not sure how fast is too fast, but I’m sure there’s such thing.]

3. A carbon tax is more efficient than a set of specific regulations. [Certainly!] It’s also less likely to be subject to changing political winds. [Is it though?]

4. We should also apply a carbon tax to imported goods. This would reward energy-efficient American firms and prod other countries to follow suit. [Hmmmm… I can’t really disagree with the general principle, but this sounds like it will require bureaucratic oversight that will be subject to regulatory capture. On the other hand, we’ve already got that.]

5. We should give the revenue collected back to U.S. citizens, to offset increases in energy prices. [Okay, but if it’s going to be revenue neutral and come with a transfer scheme, that’s going to take some detangling!]

I buy into the notion that carbon emissions create large scale externalities that will probably be more bad than good on balance. Not universally bad, mind you. And not something that humanity won’t ultimately adapt to. But I think the people who will face the brunt of the bad outcomes will be the world’s poor (who we should help migrate to better climates!).

I don’t think we can just impose “the right” carbon tax and have everything come out just right. Even though I routinely draw out the case with a supply and demand graph in class, the truth is that nobody has access to those curves in real life. But a small tax can serve to reduce the inefficiency of pollution even if we don’t get it exactly right.

The revenue neutral part is important–we’re currently taxing lots of things we actually want more of (like investment). So if we can cut those taxes by taxing things we want less of (pollution), we’re reducing two sources of inefficiency in the current setup. Of course you and I have bolder views about what policy should look like in 100 years, but restricted to a 10 year window, a revenue neutral carbon tax looks pretty good to me.

The letter dramatically over-simplifies things. Climate change is probably a problem, but probably not as big a problem as proffered by proponents of proposals to prepare for apocalypse. It’s not clear to me that we have a good idea of a) all of the effects (good and bad), b) how people will adapt, and c) how people will adapt to a changing policy regimen.

Figuring out how to handle the tax on imports will be difficult and rife with rent seeking. Unmentioned is the impact on exports. If all our trading partners follow a similar policy, there’s no problem, but in the mean time there’s a tension that will probably be resolved with some unfortunate bit of rent seeking.

I’m sure most reasonable people would agree that instantaneous change would probably be unduly costly, but it’s not clear what the right speed of implementation is.

There are some miscellaneous rhetorical points I have issue with, but I suspect those are in there to throw a bone to people who aren’t me.

I hope that 10 years from now this open letter looks a bit silly. But I also hope that 10 years from now pollution taxes start to replace more inefficient taxes. On balance, I’m happy to see the letter prodding us in that direction.