Which is worse?

Assume the existance of two books, both set entirely on Earth.
In one of them, humans make up roughly a quarter of the animal biomass.
In the other, humans make up about the same fraction as we did in the
Neolithic. Both situations are stable enough to have persisted for
centuries or even millennia. Which one would you expect to be more 
unpleasant from a modern perspective?
-- 
http://www.livejournal.com/users/james_nicoll
http://www.cafepress.com/jdnicoll
(For all your "The problem with
defending the English language [...]" T-****rt, cup and tote-bag needs)