There seem to be lots of projects, but everyone I have looked at looks abandoned etc.
Nature already does its part in those flows, for instance, enormous stocks of carbon (methane) locked in permafrost which, owing to climate change, isn't so frosty anymore.
Humans take care of the rest.
So, in terms of OSS contributions to that scene, one can explore all manner of technology related to controlling those flows, or one can explore technology which will help humans get beyond their feuding, greed, and, dare I say "ignorance" as a means of coming to grips with the human part of the equation.
I'm working with a few developers in that space; we have chosen to explore ways by which humans can actually learn how to hold civil conversations about matters that really matter. We chose to use game mechanics, guild social dynamics, and "epic quests" to engage possibly enormous numbers of people in conversation. We have a github repo and a low-key landing page for the project at [1]. This is a project which, for the time being, uses Javascript for both the front and backside, but which will eventually include an AI-augmented ecosystem to assist in conversation analysis.
Our demo platform is still an engineering prototype, by no means an MVP.
Most everything else I'm aware of (current employer included) is not open source, but feel free to reach out if you're interested in working for a climate-related software company.