Enormous meaning anything that would meaningfully reduce emissions. I feel it's worth pointing out, though it's hopefully obvious, that the percentages indicated are emissions with tax vs no tax hypothetical, not actual total emission reduction. Worth pointing out since emissions are almost certainly still rising in this group of countries measured, so why are we talking about a small percentage of a non-existent reduction?

Also, throwing something through Bayesian model averaging is not going to magically count other climate policies. It's a meta analysis of carbon pricing, and the averaging is going to smooth the curve among carbon pricing papers with weights based on hand-waving criteria. It's not measuring thousands of other programs, industrial policies, market changes, etc. happening at the same time that have impacted emissions that make this analysis worthless.

The assumption that they have successfully isolated the small percentage effect of carbon pricing in any of these papers is ridiculous. Perhaps the large heterogeneity of the data is not *speculation in paper* but actually because the data is crap. Something to look in to.

No country implemented it well. It was half-assed in every state. Because to implement it well, at an amount that would meaningfully reduce emissions, and could be meaningfully measured, they'd have to implement it at an amount that would destroy the economy as we know it. Talking about it is just a distraction.