Although today the growth rate of the world population is almost half of what it was in the 1970s, it will take only one more generation for the Earth to add to it another two and a half million people. The real problem is that this growth will be highly uneven. Whereas rich countries’ populations will remain almost stationary and grow older, poor countries’ populations will double or even triple in more underprivileged areas, such as sub-Saharan Africa, with a strong incidence of youth. Against this backdrop Livi Bacci expounds his thoughts concerning the world in the 21st century and describes the implications of disproportionate demographic development for domestic social stability in several countries, international migration flows, the balance of power among nations, and – of course – the natural environment. From the beginning of the New Stone Age to the present, the room available for every inhabitant of the planet has decreased by a factor of a thousand, thus highlighting the perception of the world’s limits – formerly remote and invisible, now near at hand and pressing. There arises an ethical imperative to address demographic growth problems in a manner that is fair and responsible towards future generations.

Massimo Livi Bacci teaches Demography at the University of Florence and is a member of the Accademia dei Lincei.