Life-LCA: case study of the life cycle impacts of an infant

The recently published first Life-LCA case study of a human being (0-49 years) did not use primary data for the "childhood and youth stage" (0-17 years). Consumption was assumed to contribute 50% of the calculated 48^th baseline year. This led to uncertainties as consumer behavior changes from birth to adulthood. Furthermore, transport emissions and environmental impacts before birth were neglected. Therefore, this paper analyzes the prenatal and infancy phase (0-3 years) to develop the Life-LCA method and database further and evaluate generic assumptions.

The Life-LCA method sets the reporting unit to newly defined prenatal and infancy phases. The reporting flow describes the range of all consumed products attributable to an infant. Primary data was collected with a sample of three study objects-a pregnant mother, a newborn baby, and a 3-year-old infant-living in Germany. The following environmental impact assessment categories are considered: climate change (GWP), acidification (AP), eutrophication (EP), and photochemical ozone creation (POCP).

Prenatal and infancy phase burdens account for a GWP of 4,011 kg CO₂-eq., an AP of 22.3 kg SO₂-eq., an EP of 10.7 kg PO₄-eq., and a POCP of 1.7 kg C₂H₄-eq. The share of the prenatal phase is around 15-20% for all impact categories. Transport is a hotspot for GWP (30-60%) and POCP (45-70%) in both phases. AP (50%) and EP (45-50%) are dominated by food products, mainly meat (45%) and dairy products (35%). For the prenatal phase, energy and water consumption at birth rank third in GWP (8%). Diapers account for 6% (GWP) of the environmental burden in the infancy phase. Assumptions made in the first Life-LCA study connect closely with the values calculated for the first three years of infancy. A remaining challenge is allocating the impacts between infants and parents and developing a methodology for assessing data quality.

Focusing on two new life phases has led to the subdivision of the "childhood and youth stage" and an extension of the system boundaries. The results' uncertainty was reduced by developing a new set of specific datasets focusing on several study objects. The case study results show the importance of primary data collection for evaluating generic assumptions. Additional studies on childhood and adolescence from 3 to 17 years are suggested for a robust assessment of the complete "childhood and youth stage."

The online version contains supplementary material available at 10.1007/s11367-022-02129-7.