When we burn fossil fuels, CO2 concentrations stay elevated basically forever in human terms. Half the burning since the industrial revolution has happened in the last ~30 years. The human population is young, so to make the kind of difference you're thinking of, it would mean a campaign of mass murder.

I'm not in it for that.

You can get a very modest difference in future emissions by encouraging the use of contraceptives, and educating girls, but it isn't going to get you out of the need for a rapid shift off fossil fuels.