Any updates on this, or promising interventions?

In your model and your answers here, just replace inaction with campaign and campaign with inaction.

Do you think this is AI safety-specific, because LessWrong pulls the people who have engaged most deeply with AI safety, and so the EA Forum is left primarily with people who aren't as into or understand arguments around AI safety?

Or, do you think this is generally bad across causes, and the EA Forum is net negative for other causes, too?

No, I don’t think this is the right way to model this. This looks a lot like the typical error people make for the original two envelopes problem.

1. Initial welfare (what does that mean?) and final welfare after inaction can differ, because the world, e.g. land use, will change even if you do nothing, and campaigns take time for their effects to materialize.
2. If you swapped the roles of campaign and inaction, you would flip the conclusion, too.

It was illustrative.

Inaction also does not in fact lead to welfare of 0 with probability 100%. There will be lots of animals suffering and many possible outcomes if we do nothing. So it's not correct to assume total welfare of 0.

If you instead set the campaign option to 0 welfare and defined the welfare of the world with inaction relative to the campaign option, you'd end up with the opposite conclusion, that only inaction reaches -1.

Avoiding the worst is meant to treat each option symmetrically. It doesn’t depend (in theory) on which option you single out to define things relative to.

(RP's practical procedure does start with inaction, but if you end up with the same probability distributions for each option in the end, the results will be the same as if you started with a different option to define all distributions relative to. I think their procedure helps ensure consistent probability assignments and is less work, compared to directly estimating each distribution independently.)

Imagine the world has welfare 0.

With inaction, the final welfare will be 0 with probability 100 %.

This is exactly a procedure you could follow for difference-making risk aversion; it's equivalent to taking the statewise difference with inaction. The welfare of the world with inaction isn't 0 with probability 100%.

RP has a model/procedure for avoiding the worst risk aversion here.

Ah, sorry, I was too quick and should have read more carefully.

However, I believe the distribution with the campaigns has longer positive and negative tails

Why do you believe this?

As chicken and egg prices increase from these welfare reforms, I would expect:

1. some shifts between crops and nature (including through substitution), but I'm clueless about which involves more suffering, so this doesn't clearly favour one or the other.
2. substitution towards beef and other pasture products, which reduces invertebrate populations substantially, and probably without making lives much worse. This would mean less suffering and so do better in the worst case.

I agree. So the worst case is that the campaigns cause lots of suffering (relative to inaction)?

I don't think this is right. I think you're still treating "Avoiding the worst" like a difference-making view. You shouldn't be thinking in terms of "relative to inaction", which itself has a highly uncertain distribution of outcomes. Just evaluate the distribution of outcomes for each option, without fixing any as a comparison option.

The question is only whether worst-case outcomes are more or less likely with action or inaction.

FWIW, the actual worst cases are s-risks, and I'd expect "Avoiding the worst" views to prioritize their mitigation, as long as we're not clueless about that.

Interventions which cost-effectively increase the welfare of vertebrates will change land use much more than inaction, and a greater change in land use increases the probability of causing lots of suffering?

It might cause lots of suffering, but it could also prevent lots of suffering, too. I think you're thinking in terms of difference-making, but "Avoiding the worst" risk aversion is not difference-making. Rather than thinking about what you cause, you should just look at both (distributions of) outcomes and ask which has more suffering in it, without privileging the results of inaction. 

Unless you believe the expected amount of wild animal suffering is higher all-things-considered than with inaction, you shouldn't really expect it to do worse according to "Avoiding the worst" risk aversion (as a heuristic; there could be exceptions).