you're answering in a binary way after my response saying it's a multifactor optimisation problem. Some people will have 2, 1 or 0 children. Improving education and healthcare also have this effect to lower birth rate. And of course everything else has to be done, low-impact transports, food, etc..

The parent comment "No it isn‘t. The single most impactful one would be to not have kids." is also again turning things into a binary problem, there is no single solution, artificial CO2 sinks are not a single solution at all, we should not skip emissions because they represent less than 2% of global emissions for the same reason

Well, first it will have an impact is our lifetime. It already has. But you have a point. But the idea is not to have no future generations. It's to have smaller generations over time. Perhaps 10-50x times smaller. This would requires a few generations to happen. Even by just having one kid 10x would be achieved in three or four generations. In theory. In practise it would create a lot of economical problems as well, because the economy would shrink a lot. We are currently not prepared for that and nobody knows how to do it. On the other hand it's a moot point, the global population is actually growing and even in rich countries it's at least more or less stable.