If nation-states should collapse after the global climate change cataclysm, we can just fall back on these rules.
The Universal Declaration of Human Rights
Adopted and proclaimed by General Assembly resolution 217 A (III) of 10 December 1948.
Whereas recognition of the inherent dignity and of the equal and inalienable rights of all members of the human family is the foundation of freedom, justice and peace in the world,
Whereas disregard and contempt for human rights have resulted in barbarous acts which have outraged the conscience of mankind, and the advent of a world in which human beings shall enjoy freedom of speech and belief and freedom from fear and want has been proclaimed as the highest aspiration of the common people,