Thank you for the links. Need to check them out more later today to see where I can help, but from first view they all looks like "We want to do something about climate change, join us if you also want to", but not much about what they actually do.
https://climatechoice.co/ (plenty of small issues up for grabs https://github.com/impactmakers/climatechoice/issues)
https://fixathon.io/ (more sponsorship opportunities available, get in touch. https://bit.ly/fixathon-sponsor)
The third link is a tracker app.