In July 2017, ScienceMag reported on a study:

Eating no meat cuts an individual’s carbon footprint by 820 kilograms of carbon dioxide (CO2) each year [...] by choosing to have one fewer child in their family, a person would trim their carbon footprint by a whopping 58.6 metric tons

http://carbonindependent.org/22.html gives

1/4 tonne CO2 equivalent per hour flying.

Are these figures accurate?

  • Note that people won't verify your calculations here – Sklivvz Jun 7 at 16:26
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    "A man shall not be held accountable for the sins of his father". Since when is it reasonable that your child's carbon footprint is akin to your own? – fredsbend Jun 8 at 5:46
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    @fredsbend I don't think your analogy is accurate. Because you do not have a say in what your father did. But you do get to say whether you have 0, 1, ..., N children. So it is a completely rational decision to say "Due to global warming I'll have only 1 child instead of 2-3 I wanted" and this decision does reduce the future carbon foot print of humanity by a certain amount. – Giacomo Alzetta Jun 10 at 14:33
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    @GiacomoAlzetta It's not an analogy. It's a quote from a very old book, which at the time gave the revolutionary idea that you are responsible for your own actions, not your family's. If that leads you into nihilism, too bad for you. The rest of us will still be here. – fredsbend Jun 10 at 23:24
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    @GiacomoAlzetta It's only rational if having less children doesn't enable others to have more children. If the maximum population is determined by food or other resource scarcity then future population will be independent of an individual's choice. – DavePhD Jun 13 at 16:50

To come up with the emission per child, the original source Reproduction and the carbon legacies of individuals Global Environmental Change Volume 19, Issue 1, February 2009, pages 14-20, is considering an infinite series.

In other words, having one child results in all the lifetime emission of said child, plus all that child's descendants' emissions. Since each child usually has two biological parents, 4 grandparents, etc., to avoid double counting, the reference weights descendants' emissions by 0.5^n, where "n" is the number of generations into the future. For example n=1 for children, n=2 for grandchildren, etc.

This infinite series is potentially divergent, if fertility rates are above 2. So the reference assumes that the fertility rate will drop to 1.85 everywhere in the world by 2050, permitting the series to be convergent.

  • Thanks, @DavePhD. Is that per parent? E.g. if my partner and I both have a child, would both of us incur the 58.6 tonnes? – Gnubie Jun 13 at 11:42
  • @Gnubie Yes, 58.6 tons per year for the mother and another 58.6 tons per year for the father according to the journal article associated with the original question iopscience.iop.org/article/10.1088/1748-9326/aa7541/…, which cites to the source in this answer. – DavePhD Jun 13 at 15:46

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