The only place where births per woman are not close to 2 is sub-saharan Africa. Thus, the only place where family planning could reduce emissions is sub-saharan Africa, which is currently a tiny fraction of emissions.
This is not literally true: family planning can reduce emissions in the developed world if the desired births per woman is even lower than the actual births per woman. But I don’t dispute the substance of the argument: it seems relatively difficult to claim that there’s a big unmet need for contraceptives elsewhere, and that should determine what estimates we use for emissions.
As a result, the gap between the number of children that women say they want to have (2.7) and the number of children they will probably actually have (1.8) has risen to the highest level in 40 years.
This is not literally true: family planning can reduce emissions in the developed world if the desired births per woman is even lower than the actual births per woman. But I don’t dispute the substance of the argument: it seems relatively difficult to claim that there’s a big unmet need for contraceptives elsewhere, and that should determine what estimates we use for emissions.
At least in the US women have been having fewer children than they want for many decades: