AI companies do not release any numbers themselves for carbon emissions.

I think the EU is even helping them keep that "operationally sensitive information" private, which is a shame.

not adding AI does not stifle environmental goals.

I can't agree or disagree here. I know the demand for AI is huge: hundreds of millions of users per day and at least a billion per week. If Ecosia is seen not to have this feature, I would consider it possible that it hurts their adoption and therefore their goals.

which shows how incredibly dirty AI can be, even if no one releases any sensible metrics.

Yes. I'm not sure how much solace the "world greenest AI" slogan can really offer in that context. https://blog.ecosia.org/ecosia-ai/ - but when I'm recommending search to someone, I recommend Ecosia over Google, Bing, DDG, Qwant, Mojeek, etc. simply because I think they are more of a net positive than the other options.

Who knows, maybe in a year or twos time I'll look back and regret it when more information surfaces. But they've been sensible enough until now with their operational choices to reach tree-planting goals.