Eugenics? What eugenics? There is no mention of eugenics in this research paper. 
Just the eco-fascist narrative that climate change isn't caused by capitalism, but by too many people consuming resources faster than they can be replenished. I'm sure that's not a dangerous idea useful to anyone or anything. 
It's obvious no serious discussion can be had here. 
Human society has this cool system called capitalism that generally deliberately wastes anywhere between 10-90% of harvested resources depending on industry. Fossil fuels should already be borderline redundant resources, large scale farming companies frequently have lower yields per square metre and higher soil depletion, somewhere between 50-70% of food doesn't get eaten, over half of clothes don't get used more than a couple times (and 10-30% don't get used ever). Food, clothes, furniture, extremely expensive electronics and even cars get deliberately destroyed in brand-new condition because profits.
Given we're working at a fraction of the efficiency we currently should be, I struggle to believe "we have too many humans to support" arguments have much basis in facts (instead of more of a basis in just aligning with desired ideology) until we address that first thing.
Instead it's more "I can't imagine how society might change to not be enormously wasteful so instead billions should die".
this needs to be pasted all over r/collapse. i hate that there is sometimes useful info there (they were really ahead on covid) but seems the eco-fash have basically taken over what used to be more 50/50 leftist/eco-fash liberal
but then again it's
/r/collapse used to be mostly left leaning, if a bit lib and doomer sometimes. At some point, it got an influx of right wing reactionaries, and it was pretty much over then. They used to heavily police eugenicist rhetoric, and it mostly served as a climate change space that wasn’t just techno hopium about how carbon capture and nuclear power were going to save the world.
i get the doomer stuff. my theory is that the majority are super-depressed libs, and see any collective left action as too impossible/exhausting. so the few that aren't just of the "i will end my life the instant the power goes out" are just hoping the eco-fash take care of things for them
i mean, they're probably white and comfortable and figure they will survive purges restricted to the borders and the Global South