Civilization is collapsing and taking nature with it. There is no ethical consumption under capitalism - from a vegan standpoint and a collapse standpoint. Each human is another consumer and contributes to the destruction. It can't be helped in this system. So right now we need less not more. And children are being born today that will likely suffer tremendously due to climate collapse in their lives. Even without collapse, more humans means more animal harm. I think those are some of the common ideas.