You probably need to study birth control in context of the collapsing economies of countries like Japan, Korea and China

Are you insinuating that accidental and unwanted pregnancies would help their plight?

I'm saying that having less children is not necessarily good for the environment.

Do you mean economy? Your comment doesn’t mention the environment.

OP: “preventing unwanted pregnancies is good for environment” (because humans have big carbon footprint)

You: “having fewer children is bad: see these economies”

This reads as criticism of birth control and the viability of population reduction as an environmental strategy. But:

1. Do unwanted children typically contribute positively to GDP? Isn’t reducing that terrible situation just a win on all fronts?

2. How is collapsing population in developed countries related to the OP’s suggestion of widespread birth control? Are they really that related?

3. How is having fewer kids bad for environment? Afaict it is unambiguously good for that.

Why?

How are those countries' collapsing economies harming the environment?

Also why would I want to fix an economy using unwanted children?