Letter: Crowded world

Sir: A further 3.5 billion increase in population during the next 50 years has enormous implications for the economic and environmental stability of the world, as well as for those individuals unfortunate enough to live in countries where the population is expanding rapidly. Countries such as Egypt are horrendously over-populated already and can only get worse.

The world will be overcrowded by mid-century, and the fact that the population will fall towards the end of the century is scant consolation to those who will suffer in the meantime.

MATT WALKER

Abingdon, Oxfordshire