Ask HN: How to contribute towards a sustainable society as a software engineer

I'm passionate about sustainability and am considering going to 80% time at work so I have one day a week to devote to problems around growth/environment.

However I have no idea what I'd do in this time, and if it would be worth it (e.g. an alternate idea would be to donate the equivalent amount in salary to an environmental charity).

Do you know of any organisations that require software engineers (or people with these kind of skills) that would be able to use remote work? If not, is there anything actionable I could do on an individual level within the 1-day per week time constraint?