Sir – Matt Oliver does well to inform us (Report, November 27) that Oxford City Council is under pressure to deliver 28,000 homes by 2031.

What urgently needs to be included in the debate are findings by arguably the most comprehensive analyses of the capacity of land to support ever increasing populations, that of the Global Footprint Network (http://www.footprintnetwork.org/en/index.php/GFN/).

They look at the land needed not only for building houses, and of course the concomitant schools, shops, factories, roads etc, but also for food production, for absorption of rainfall to provide water, green spaces for recreation etc for steadily increasing populations. They estimate that the UK is already overshot by about three times: we have 64 million people on land that is estimated to support about a third of that.

We meet the shortfall by importing food and energy on a large scale and, like headless chickens running towards a cliff edge, are adding over 400,000 persons annually, split roughly equally between excess births over deaths and excess immigration over emigration.

The source countries from which we import our food and energy shortfalls will not have a surplus for much longer. World population, currently at 7.1 billion, is increasing by some 86 million per year.

Those already alive to the potential threats of climate change should reflect that climate change is driven by climate changers — we humans. Given these existential threats is it too much to ask that parents consider having just one or two children, or even none if so inclined?

Richard Vernon, Oxford