It's actually really cherry-picked samples. All messages (blue and green) in the Messages app fade out slightly as you scroll. The author picked a blue message from the bottom of the screen and a green one from the top. If only they scrolled around a bit... they would have noticed.
The core of the climateAction.tech at the moment is in a Slack, where different projects are moved forward by the community. There are a bunch of different things happening but recently some of our members where behind the https://digital.globalclimatestrike.net. A couple of things I know are being worked on include putting more pressure on AWS to switch to renewables faster and an idea for a green open-source license
Dropping in here just to say: if this got you worried, come work with us over at http://climateaction.tech/ We are a global community of tech professionals using our skills, expertise and platforms to support solutions to the climate crisis.