Jared Diamond says:
– societies collapse. examples a many, old or recent. It was worse in the pre-historic times (i.e. before writing existed – think Maya) because lessons from the past could not be captured
– ecology is twofold. First-world ecologist think about solving their societies. Global ecologists (Diamond is clerly of the latter) think about solving world issues, which are many (he cites 12), but upmost overpopulation.
– we’re doomed.
– William Rees explains it is « a necessary antidote » to followers of Julian Simon [in Wikipedia article on Collapse]