We can't even agree on carbon. There's no way we can agree on something like that. People are too busy surviving individually to worry about survival of the species.
Not with that attitude.
It's not so much that we "can't agree" but more that the main argumentative mode these days is sneering and insults, occasionally backed up by mob violence. No wonder people get stubborn about sticking to their positions.
(And since you brought up the topic of sneering and insults, frankly, the only time I've felt insulted at at on this site recently was your "Not with that attitude" comment. Perhaps you're assuming some kind of ill will or political motivation on my part that was not in fact there. Regardless, your comment still reads like a sneer to me, three days later.)
So how can we change what people value, without destroying that which we are attempting to preserve?