Sir, – It's pretty rich of Seamus McKenna (September 2nd) to ask for people to acquire "some acquaintance with mathematical principles". Although the human population is obviously still increasing, what has declined (and probably permanently) is the rate of growth. The population of the world reached seven billion in 2011, six billion 13 years earlier, and five billion 12 years before that again. In other words, the most recent billion was reached more slowly than the previous billion. And this will continue.
If Mr McKenna survives to the year 2050, he could well see world population actually decline and the policy debate will be exactly how generous states will have to be, in terms of maternal and paternal leave, to encourage couples to have babies. – Yours, etc,
FRANK DESMOND,
Evergreen Road, Cork.
Sir, – There must be an optimum population that balances quality of life with quantity of people.
The number for this optimum population will be a matter of opinion, depending on what people regard as a good quality of life. Broadly speaking, if we want everybody on Earth to live as we do in the “West” (a child born in Europe today is set to use around 30 times the amount of energy over a lifetime than a child born in Africa), then at seven billion people, we are already past the carrying capacity of the planet, which is the Thomas Malthus scenario.
At the other extreme, if we could all be satisfied with an acre or two of land, exist as subsistence farmers and travel by horse, then the planet could support over 30 billion people, and still leave room for a few wild plants and animals.
What is certain is the Earth isn’t getting any bigger but our population and, more importantly, our energy use are growing. – Yours, etc,
CIARAN FARRELL,
Ocean Point,
Courtown, Co Wexford.