The study, led by Julia Sborz of the Norwegian University of Science and Technology together with colleagues including Juudit Ottelin, set out to test a hypothesis drawn from environmental economics. The Environmental Kuznets Curve proposes that environmental degradation first rises with economic growth and then falls after a turning point, as societies become rich enough to demand cleaner technologies and better living conditions. If that logic held at the household level, Norway would be the perfect place to see it in action. The country ranks second on the Human Development Index, held the eleventh largest material footprint per capita in 2023, and has experienced relative decoupling between economic growth and territorial emissions. If ever a nation sat on the downward slope of the curve, it should be Norway.

To find out, the researchers combined two very different accounting traditions. On one side, they estimated material stocks: the physical mass of materials locked into dwellings, holiday homes and passenger cars owned by Norwegian households. On the other, they calculated material footprints using multi-regional input-output analysis, a consumption-based method that traces all the raw material extraction, biomass, minerals, metal ores and fossil fuels required across global supply chains to satisfy each household’s annual spending. The team drew on the 2022 Norwegian Consumer Survey, covering 3,435 households after exclusions, and matched dwelling types and construction cohorts to material intensity estimates for Norwegian buildings. Cars were assigned the 2022 national average weight of about 1.6 tonnes, while cabins were assumed to average 83 square metres, the national figure for holiday homes built between 1983 and 2024.

The results reveal a pattern that challenges the dematerialisation narrative. There is a weak-to-moderate positive correlation between per capita material stocks and material footprints, with a Spearman coefficient of 0.314. More strikingly, a log-log robust regression model controlling for income, wealth and household size found an elasticity of roughly 0.1: a one percent increase in household material stocks per capita is associated with about a 0.1 percent increase in annual material footprint. The effect is small but statistically significant. For a typical two-person household, moving from a 50 square metre apartment to a 120 square metre one could raise the material footprint by around 1.2 tonnes per person per year, holding everything else constant.

The geography of household stocks turned out to be full of counterintuitive twists. Apartment dwellers, often assumed to live lightest on the land, actually carried the highest dwelling material stock per capita. That is because apartment blocks have higher material intensity per square metre, and their residents are typically smaller households, averaging 1.53 people compared with 2.36 for detached houses. Single-family homes hold the largest stock per household at 175.7 tonnes, but when divided among more people, the per capita advantage shifts. The finding matters for urban planning: if smaller apartments simply attract solo dwellers rather than reducing floor area per person, the expected material savings of compact housing can be erased or even reversed.

Cars told their own story. Car stock contributed the least to total household material stocks but showed a clear gradient, declining as centrality increased, meaning the closer households lived to major urban centres, the fewer vehicles they owned. Detached-house residents owned the most cars, averaging 1,112 kilograms of vehicle stock per person, against 632 kilograms for apartment dwellers. The researchers point to parking as a plausible mechanism: Oslo’s zoning rules allow one to two parking spaces per residential unit for houses but only 0.5 to 0.9 spaces per 100 square metres for apartment buildings. Car stock also correlated positively with cabin ownership and negatively with per capita dwelling stock, hinting at trade-offs and interactions between the building and vehicle components of household wealth.

One of the study’s most elegant findings concerns the difference between wealth and income. Wealth, a financial stock, correlated more strongly with material stocks, which are also stocks, while income, a financial flow, tracked more closely with material footprints, which are flows. The material and financial dimensions of household life mirror each other in form. This distinction helps explain why earlier research produced conflicting results: everyday footprints may not rise with wealth, but footprints that include capital end up doing so. In Norway, where housing mediates intergenerational wealth transfer and explains roughly 12 percent of wealth persistence, the connection between property and prosperity runs deep.

The authors are careful about the limits of their cross-sectional design, which captures a single moment in time and cannot establish causation. They also note that their footprint estimates, averaging 10.64 tonnes of materials and 5.77 tonnes of carbon dioxide equivalent per person, are lower than earlier Norwegian studies, partly because household budget surveys tend to underestimate spending, particularly among the highest consumers, and because construction and aviation categories are imperfectly matched between survey and input-output classifications. Air travel emissions in their estimates, around 112 kilograms per person, fall well below independent estimates of Norwegian aviation emissions, a gap the authors attribute to survey underreporting, revised database intensities and pandemic effects. Stocks were also limited to dwellings, cabins and cars, excluding appliances, secondary residences abroad and collective infrastructure such as roads.

Even with those caveats, the central conclusion stands firm: material accumulation does not behave like the technology effect that Kuznets-curve theorists hoped would lighten humanity’s footprint. Instead, stocks appear to lock households into ongoing resource demand through maintenance, renovation and the consumption patterns that large homes and multiple vehicles enable. The researchers frame this as a household-scale version of the carbon lock-in documented for infrastructure, and they connect it to doughnut economics, which asks societies to meet everyone’s needs within planetary boundaries. Norway has comfortably achieved the social side of that goal, but its households keep pushing against the ecological ceiling. The authors argue that waiting for rising incomes and accumulating assets to deliver environmental relief is a losing strategy, and that systemic changes are needed to incentivise living well with less material stock rather than more.

For a world of growing cities, shrinking households and expanding holiday-home markets, the message is uncomfortable but clarifying. Every additional tonne of steel, concrete and timber woven into private property carries a hidden tail of future consumption. Breaking the loop will require more than efficient technology; it will require rethinking how much stuff a good life actually needs.

Subject of Research: The relationship between household material stocks and material footprints in Norway

Article Title: The more you have, the more you want? Analysis of household material stocks and footprints

Article References: Sborz, J., Li, J., Rousseau, L. S. A., Müller, D. B., & Ottelin, J. (2026). The more you have, the more you want? Analysis of household material stocks and footprints. Journal of Industrial Ecology, 30(4), 1817-1834. https://doi.org/10.1007/s44498-026-00124-x

Image Credits: AI Generated

DOI: 10.1007/s44498-026-00124-x

Keywords: material stocks, material footprints, household consumption, Environmental Kuznets Curve, input-output analysis, Norway, dwellings, car ownership, holiday homes, wealth, income, planetary boundaries