And no, to be clear, the problem is not overpopulation because Earth is not overpopulated.
The problem is a handful of rich countries spending a century building a culture filled with cheap disposable commodities, powered by setting fire to irreplaceable resources and oppression of those more vulnerable. Because a few people decided it was profitable, and lots of others didn't argue because it was convenient.
The problem is that humans are greedy and wasteful, and we need to stop.
The point is not that greed or wastefulness are inherent human traits. They're not. This has been proven repeatedly, and societies would not have formed to begin with if this were true.
The point is that humans did this. We are humans. We can and must undo it.
Sunbeam City is a anticapitalist, antifascist solarpunk instance that is run collectively.