There are no rational limits for breeding as the technology solved this problem before. The universe is enough place for all.
Also in the past people lived in more material poverty but were not lesser happy - what shift material limits further than it seems. You can feel good without many things in your life, but you can't without love.
There is a lack of love to people. Today egocentric ideology indoctrinated to masses leads to the hate to people and hence to born new ones. It's what is the real loss. It's part of peoples' nature the wish to born new people. Of healthy nature. Anything other is the pervertion which leads people to be unhappy.
What is the sense in having more expensive things and more of them if you feel worse, lesser happy? When the love is lost, the inner harmony, the natural part of which is to born children. The egocentric ideology have stolen this from people. Also with more natural attitude - people could do more to have better material region. Many resources goes away due to egocentrism as people do not care about others as could and due to intersocial conflicts with this egocentrism.
The peoples quantity is not the real problem. The perverion of peoples' psyche and socium by egocentric ideology - is the far more problem. While the talks about "there are too much of people" is more the rationalization of hate to people than other.
I was born in other culture - USSR collectivism. It's easier for me to see the situation differently.
You need to think to understand what I've said. Medias propaganda is not easy to overcome.
I have nothing to add still.