it's not the belief that's in question. It's the actions required.
I, and many others (whether they admit it or not), do not wish to make personal sacrifices to fix climate change, if others are not willing to make the same level of sacrifices (such that relative positioning within society does not change).
This is why i think we need global policy changes and regulation to achieve the commonly beneficial goals.
While I agree we aren't the nicest species of primate (that title goes to our cousins, the Bonobos), I also believe a lot of our nastiness can be attributed to nurture rather than nature.
My feeling is that any individual is OK with sacrifice as long as they are not unfairly disadvantaged relavitely to their society/neighbours.
For example: i would not be willing to pay more income tax unless this applied for everyone; even if i wanted higher income taxes.