> I guess that sort of response begs the question of if there is even anything greater to which humans owe some moral obligation
Nobody can prove that there is. Lots of people have faith in a higher power of some kind, or objective morality. Nobody can provide scientific evidence for it. Far as a I can tell, natural is amoral and doesn't care. And humans have never agreed as a whole on what that something greater is.
I basically realized there was no god/religion was just wishful thinking at a very young age, but I sort of held onto the idea that we could all agree that keeping the Earth habitable for humans was a worthwhile endeavor (I mean, most people seem to want to have kids, right?). But in the last decade or so I’ve even lost that belief.
It's not so much people disagreeing about keeping the Earth habitable and more so disagreeing about what that means or entails. I don't see any realistic scenario where the planet is inhabitable for humans, but certainly things can make it less habitable for what will be 10 billion people and many other life forms.
Nobody can prove that there is. Lots of people have faith in a higher power of some kind, or objective morality. Nobody can provide scientific evidence for it. Far as a I can tell, natural is amoral and doesn't care. And humans have never agreed as a whole on what that something greater is.