Climate
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.
The one dependable thing has always been that all models end up underestimating results. "Worse/faster than expected" was never funny, but now it's so cliche that I don't even see it mentioned much anymore.
There goes my avacado toast stocks
Half of planet's population dead is more like it.
We are going to be 40% poorer regardless.