You use a lot of adjectives, but not a lot of numbers.

How much of a problem is this actually? Eg what proportion of our overall emissions (or environment impact etc) are from the manufacture and supply of clothing? And how much extra is from 'fast fashion' vs a return to old fashioned clothing habits?

I just did a very quick search, and found eg https://ourworldindata.org/emissions-by-sector Their numbers suggest that cotton and clothing barely show up.