In any context, using "population control" or "population reduction" is never okay.
Your intentions may not be malicious, but given the genocidal history of that phrase, it is best to not use that framing.
technologyreview.com/s/614682/criti…
This isn't new. There's a long history of well-funded Malthusian overpopulation alarmism.
But we should do it because it's the right thing to do. Not because it helps climate. @JosephMajkut put it well:
That's what all these arguments around population control come down to in the end, and it's offensive.
It is the woman's decision, and hers alone.
Y'all need to butt out.