[sprucevoid]

> reads to me as

That was not the intention with that claim. I meant to convey something more minimal: if you after investigation have no strong reason to think either is environmentally worse then let animal harm considerations break the tie.

> suppose I source my wool from sheep that are kept well, but have shorter lifespans. If I'd then switch to cotton, I'd contribute to entire ecosystems being impacted due to water usage.

What does "kept well" mean? If a sheep was really treated well in the sense of it not being subjected to the many harms that 99% of all sheep currently are subjected to and was individually cared for, including appropriate food and veterinary attention, then it would likely live much longer, unless someone kills it while still healthy and with years left to live, which does not sound like "kept well". Also, the water usage comparison depends on what type of cotton production you're comparing to, since there exists recycled cotton and various smaller scale production methods geared to reduce water usage.

As for the climate impact of wool see https://www.vox.com/future-perfect/24008053/wool-marketing-e...