If you have a child, the first thing you want is that the child is safe and healthy.
And you start to think what can you do better and what should change in the world so that your kid/baby has it better.
So in the end, if just 50% of the scenarios of climate change are true, you will change your behavior.
It's the same with eating candy or other unhealthy stuff. You will stop eating it because you want to show your kid/baby what is healthier for her/him.
So I would say we need more kids in the world if we want to have a better future.