I think that overpopulation is a real problem. It's just another one of
those things no one, especially politicians, likes to talk about. The new
limits to growth scenarios seem to indicate that the human population may
have already overshot the carrying capacity of the planet. We've done this
using relatively cheap food produced by fossil fuel inputs in agriculture.
I don't think anyone is recommending mass extermination programs. It may not
even be necessary to do much intervention. In many countries, including
where I live in T&T, falling sperm counts in males are contributing to much
reduced fertility levels. I'm not sure what is causing this, maybe certain
hormones fed to animals, or chemical pollutants like plastics.
I think all the things being mentioned are important to restore
sustainabilty: population control, reducing levels of consumption,
non-growth economics, buying locally produced foods etc etc. It may not be
effective just to focus on one strategy.