Even the widely cited figure on the benefits of having “one fewer child” needs to be understood in context. A 2023 study estimated a potential annual saving equivalent to 58.6 tonnes of CO₂ from having one fewer child in developed countries. The calculation included shares of the emissions of children and their descendants, spread over the expected lifespans of each parent, assuming that the prevailing emissions rates at the time would continue. It is a calculation of a carbon legacy passed down through generations, and its outcome changes dramatically when the way energy is produced changes.
