Intended for healthcare professionals


Voluntary family planning to minimise and mitigate climate change

BMJ 2016; 353 doi: (Published 20 May 2016) Cite this as: BMJ 2016;353:i2102
  1. John Guillebaud, emeritus professor of family planning and reproductive health
  1. Institute for Women’s Health, University College London, London WC1E 6BT, UK
  1. j.guillebaud{at}
  • Accepted 18 March 2016

John Guillebaud calls for action to tackle the effect of a rapidly growing world population on greenhouse gas production

Simply put, climate change is caused by excessive production of greenhouse gases. As highlighted by the late Professor Tony McMichael, the “cause(s) of the causes” should not be overlooked.1 With climate change already close to an irreversible tipping point, urgent action is needed to reduce not only our mean (carbon) footprints but also the “number of feet”—that is, the growing population either already creating large footprints or aspiring to do so. Wise and compassionate promotion of contraceptive care and education in a rights based, culturally appropriate framework offers a cost effective strategy to reduce greenhouse gases. This article outlines the evidence for voluntary accessible family planning as a strategy to reduce greenhouse gas emissions and mitigate climate change.

Every week, world population increases by 1.5 million

Phil Testemale

What is the relation between population and environmental impact?

During 1971-72, Ehrlich and Holdren identified three factors that create humanity’s environmental (including climatic) impact, related by a simple equation2:

Environmental impact, I =P×A×T

in which A is affluence (material consumption and the concomitant “effluence” of pollutants such as carbon dioxide (CO2) per person); T is technology impact per person (in which fossil fuels measure more highly than solar based energy); and P is population (the number of people).

Population’s effect on the other two factors is multiplicative. Reducing P can reduce environmental impact if the other factors are constant. In fig 1, for example, fewer people requiring food would manifestly reduce the startling 30% of greenhouse gas emissions from agriculture and meat production combined (including CO2 from deforestation, methane from livestock, and nitrous oxide from fertilisers).3 That said, other contributory factors, including the worldwide trend towards higher meat consumption, must also be reversed.

Fig 1 Greenhouse …

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