Interestingly, the portion of people who value fighting climate change so high that they'd be beneficial to that end is so vanishingly small on the scale of the entire planet that if they decide to have fewer children then they're probably making things worse by letting themselves get outbred by people who care more about other things (first and foremost, improving living standards).
And no, young people in general do not care that much about the environment compared to much more immediate issues such as poverty. Young affluent people in rich countries do, but then it might also be that we've spent the last decades literally telling them they'll die burning at 40 and they might not have understood that was hyperbole.
And no, young people in general do not care that much about the environment compared to much more immediate issues such as poverty. Young affluent people in rich countries do, but then it might also be that we've spent the last decades literally telling them they'll die burning at 40 and they might not have understood that was hyperbole.