It's an interesting philosophical question.

Let us take it as read that if you have children, you are morally obliged to work to ensure that the planet is habitable for them and future generations. But if you choose not to have children, do you have any moral obligation to ensure the planet can continue to support life after you have died?

I could foresee a future when more-or-less everyone agrees that something drastic would have to be done to save the planet, but an electorally-significant block simply say "don't care, dead soon, so long and thanks for all the fish".