I've been working in the nonprofit space for 10 years and trust me when I say that we need highly capable and motivated tech professionals. Go here and start looking at job postings in your country: https://en.wikipedia.org/wiki/List_of_environmental_organiza...
No one person will solve a planet-scale issue like climate change, but each person who decides to pick up a bucket and start bailing water will mitigate the impact. Be the change.
* Climatescape: https://climatescape.org/
* Climate.Careers: https://climate.careers/
(Disclaimer: I know the people who created both of those, so I guess I'm biased as to their quality, but I really do think they're very valuable resources.)
There are also some great Slack groups for technologists who are worried about climate change:
* https://techimpactmakers.com/
I'm also part of the Sunrise Movement[0], which has significantly pushed US politics in the direction of actually doing something about about climate change. I'm working on various software projects for them, and would love to help anyone who's interested get involved in that. Feel free to email me -- my email's in my profile.