The paper (https://www.biologicaldiversity.org/programs/population_and_sustainability/pdfs/OSUCarbonStudy.pdf https://www.biologicaldiversity.org/programs/popul

The paper (https://www.biologicaldiversity.org/programs/population_and_sustainability/pdfs/OSUCarbonStudy.pdf https://www.biologicaldiversity.org/programs/population_and_... ) cited by the paper (http://iopscience.iop.org/article/10.1088/1748-9326/aa7541/meta http://iopscience.iop.org/article/10.1088/1748-9326/aa7541/m...) cited by the article says an interestingly different story: lifetime emissions of CO2 that are saved by different actions (US) Increase car’s fuel economy from 20 to 30 mpg 148 Reduce miles driven from 231 to 155 per week 147 Reduce number of children by one: Constant-emission scenario 9,441 Optimistic scenario 562 Pessimistic scenario 12,730 So basically fighting climate change, or having kids who consume less, has a much greater impact.