So, carrying capacity is a real term ecologists and biologists use to describe the capacity for a given area to sustain a given population of a species - i.e. 10 acres of land can feed a population of 5 cows (idk the real numbers I'm just making stuff up for this example).

The problem is that eco-fascists will hijack the language to say that "the carrying capacity for human beings on planet Earth has been exceeded" and then imply that we need to get rid of the excess population (that's always conveniently located in the third world) urgently "somehow".