Sadly this isn't true. The changes required to make any significant difference would likely involve the end of capitalism as we know it, and thus they will never happen until a catastrophe occurs. You're living in a dreamworld if you think even something like the Paris accord is anywhere close. And climate change is just one small way in which we are ruining the world. Imagine what things will be like with 10 billion! Yet population control is taboo because fee fees. It's liberalism gone suicidal.
This seems to me one topic where HN has its head jammed firmly in the sand - population control goes against its dogma, yet unrestrained fertility will likely destroy the planet but hey, we had 50% female engineers for 2 weeks before the polar caps melted!