How Much CO2 is a Child? Updating the Carbon Legacy

Emmanuel Pont , INED

Population growth is widely recognized as one of the main drivers of greenhouse gas emissions that cause climate change (Dhakal et al. 2022). However, the nature and evaluation of this link are controversial and debated (van Dalen & Henkens 2021, Muttarak 2022, Véron 2022). Of particular concern to individuals is the environmental impact of their own fertility choices (Schneider-Mayerson & Leong 2020). The figure of 60 tons of CO2 per child has been widely circulated (Wynes & Nicholas 2017), building on the so-called “carbon legacy” calculation (Murtaugh & Schlax 2009). This method has been heavily discussed, mostly from a philosophical perspective (Pedersen & Lam 2018, Pinkert & Sticker 2021), and suffers from several issues. In this study we present an alternative computation of the carbon legacy of a child in different countries using long-term SSP emission scenarios (Meinshausen et al. 2020), UN population prospects and a differentiated profile of emissions by age (Zagheni 2011). We combine this calculation with several possible formulas for philosophical responsibility, adding nuance to the original maximalist causal responsibility. We find that, in developed countries, the carbon legacy of a child is much smaller and comparable to other individual actions. It is even less for a “green child” or with more common philosophical representations of responsibility. We conclude that current household emissions and their future trajectories are of much higher importance than the choice to have one more child.

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 Presented in Session P109. Carbon Emissions and Environmental Policies