"with something like twenty-five million new mouths bawling for food every year"
Population Explosion
Creative Commons Attribution Share AlikePopulation Explosion - Credit: K.boroshko

Though the concept of 'the population explosion' was not in vogue when this novel was written (Paul Ehrlich's The Population Bomb was not published until 1968), Wyndham makes it clear that the consequences of rapidly increasing human numbers were starting to worry people.

The 1950s was the decade in which the human population began rapidly to escalate: at the beginning of the decade the world's population was about 2.3 billion; it increased to nearly 3 billion by 1960. Wyndham's 25 million extra mouths per year was correct in 1951, but the rate of increase jumped to nearly 50 million more each year during that decade.