Ask HN: Sustainable Alternatives to Amazon S3?

I'm researching ways of building and pitching more sustainable development to clients, from avoiding face to face meetings (COVID helped with that one!) to proposing data centres that reuse waste generated heat.

One thing I'm struggling to find a more sustainable alternative to Amazon S3. Lots of clients have sites that require fast asset access, and from all across the globe.

Obviously the most sustainable option would be reducing asset heavy sites full stop, but for those cases where it's not possible is there a more green CDN than S3? Or does the need for excess capacity sitting around the globe undermine the whole exercise from the start.