[nmrm2]

You seem confused about the point of plastic bag taxes/bans. The purpose of plastic bag taxes isn't to "price-in" an externality; rather, the purpose is to fundamentally change consumer behavior.

More generally, the language of economics ("pricing-in externalities") doesn't make sense when discussing irreversible damage to the environment:

1. When you can't repair the damage, the idea of "pricing-in" externalities is just confused thinking. (You can't buy a new planet and not all environmental harm can be reversed by spending money. At least for now.)

2. For any consumer behavior that causes irrevesable damage to the environment, the cost is at once too large to quanify and also too small to notice. (Many forms of pollution have highly nonlinear effects on the environment that are often impossible to quantify, especially at a global scale. I have no idea how anyone would go about calculating the "cost" of a lifetimes' use of plastic bags or fossil fuels, for instance, especially when you have to add up the permanent loss of a resource to humanity for the rest of the time it's on the planet.)

[stale2002]

OK then, let's say that for every plastic bag someone uses they are charged 1 million dollars.

Do you believe that this would "price in" the cost of a plastic bag? Do you believe that, given a million dollars for every bag used, the government could clean up this supposedly irreversible damage?

I believe it could. Not only that, I believe the price would be much less than 1 million dollars.

Or how about this. Let's say they instead used that money to fix a completely different problem that is also causing permanent damage, and is equal or worse than the damage caused by plastic bags.

There is always a price. There are always trade-offs and opportunity costs.

[nmrm2]

> Do you believe that, given a million dollars for every bag used, the government could clean up this supposedly irreversible damage?

You're missing the point.

If you charged a million dollars for every bag used then basically no one would use plastic bags. Or at least few enough people that the aggregate environmental impact would be negligable. As it turns out $5 or $10 would probably work as well as $1M.

The whole point is that it's totally impossible to come up with realistic estimates for something like plastic bag waste. So you set the prices high enough to disincentivize their use.

The purpose is the disincentive, not actually putting accurate prices on externalities. Confusing these two things is the source of the confusion in SilasX's original post.

[pdonis]

> it's totally impossible to come up with realistic estimates for something like plastic bag waste.

If it is, then it's also totally impossible to show that plastic bags are harming the environment enough to make draconian regulation a net gain.

In other words, the real purpose of the regulation is an arbitrary exercise of power: some people just can't help telling other people what to do, and when those people get to write laws and regulations, this is what you get. "Saving the environment" is just the latest ad hoc justification.

[nmrm2]

Yeah right there is not a single genuine environmentalist in the whe world. They're all just control freaks hell bent on messing with your life /s

[SilasX]

>The purpose of plastic bag taxes isn't to "price-in" an externality;

Maybe, maybe not; I was responding to a poster who was justifying it on that basis.

>More generally, the language of economics ("pricing-in externalities") doesn't make sense when discussing irreversible damage to the environment:

>When you can't repair the damage, the idea of "pricing-in" externalities is just confused thinking. (You can't buy a new planet...

Well, you can repair the damage from plastic bags.

>2. For any consumer behavior that causes irrevesable damage to the environment, the cost is at once too large to quanify

If your model contains infinities, it's automatically unhelpful; that takes you into Pascal's Wager territory. If the damage is infinitely bad, then it it would justify draconian measures against even trivial risks of too many plastic bags. But however bad they are, they're not infinitely bad. Such a model would justify arbitrarily high bag fees, not some piddling ten cents with the hope of changing long-term consumer behavior.

[zardo]

>If your model contains infinities, it's automatically unhelpful; that takes you into Pascal's Wager territory. If the damage is infinitely bad, then it it would justify draconian measures against even trivial risks of too many plastic bags. But however bad they are, they're not infinitely bad. Such a model would justify arbitrarily high bag fees, not some piddling ten cents with the hope of changing long-term consumer behavior.

Sometimes that's the reality of the situation, there are things that cannot be priced. That's why we don't consider a murder tax an acceptable way to deal with homicide.

[SilasX]

We also don't treat murder as being infinitely bad, and we reject policies that would decrease the murder rate because they would cost us in terms of something else we value e.g. privacy and convenience.

[zardo]

I didn't mean to imply that it has infinitely negative monetary value. I mean that it is a sort of wrong that cannot be undone by money.

[SilasX]

It's the same principle -- however bad some harm X is in the abstract (be it death or environmental catastrophe), it doesn't justify arbitrary measures to fight it, be it more cameras tracking your movement or $20/kg taxes on plastic bags, because in every practical sense the actual harm is bounded.

[nmrm2]

> Well, you can repair the damage from plastic bags.

Maybe. Maybe not. Maybe you can, but the costs to the environment involved in doing so are prohibitive. In any case, I don't think it's totally obvious that this is actually possible ATM.

> If your model contains infinities, it's automatically unhelpful; that takes you into Pascal's Wager territory

Yeah, well, reality > model. Unless we colonize space, destroying earth = infinity. So the implication of your statement is that pricing is a bad model for certain types of environmental damage. However...

> would justify draconian measures against even trivial risks of too many plastic bags.

...the realistic impact of most types of irreversible environmental damage has no known bound, but is not infinite.

Difficult-to-bound unknowns also make it impossible to quantify damages a priori at the level of detail necessary for pricing. Again, reality > model, so accurate pricing is a bad mechanism.

I think there are reasonable arguments against plastic bag bans. But trying base policy on an accurate accounting of the cost of long-term or irreversible environmental damage is a fool's errand in many cases.

(Also, note that my point is that in general, pricing environmental externalities is weird. Plastic bags aren't even nearly the best example of this, but are illustrative of the most common solution -- don't price, disincentivize.)

[SilasX]

It sounds like you're saying you don't know how bad X is relative to other things, and nobody can make an estimate, but it's definitely not infinity, and the possibility of X favors your preferred policy over others.

That doesn't sound like it justifies any one tradeoff over another, nor tell us how we should decide to.

[specialist]

What's your best estimate for cleaning up the Great Pacific Garbage Patch?

You've heard of the precautionary principle?