Should we limit family size to save the Earth?
Unfortunately, the headline of this article mispoke the question. We cannot "save the Earth," because it doesn't need saving. The planet we live on, for the moment, gets along just fine with or without us.
What we can do is reduce the impact of humans on the Earth and all of its species by responsibly controlling and limiting our own population growth, before Nature does it for us. This will earn us the ability to exist on this Earth a little while longer.
Human consumption and waste production are a function of population numbers times rate of consumption. It's a zero sum game. Either reduce consumption across the board or drastically reduce human population growth.