Climate - truthful information about climate, related activism and politics.
Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.
As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades:
How much each change to the atmosphere has warmed the world:
Recommended actions to cut greenhouse gas emissions in the near future:
Anti-science, inactivism, and unsupported conspiracy theories are not ok here.
https://www.youtube.com/channel/UCxG5KAao5rJY3vvwbVUSv4g - The "This Is CDR" series is particularly good. OpenAir Collective is all-volunteer and focused on carbon dioxide removal (which is secondary to eliminating fossil fuel use, but it is something I can actually work on and make progress). In the long run, CDR is no less vital than decarbonizing.
I'm going to recommend Climate Change with Katharine Hayhoe, though in general, I find that video is a terrible way to encounter content if you want to be able to think critically about it.