Our sources
For many products we state an indicative CO2 saving compared with the conventional, non-sustainable alternative. This page shows what those estimates are based on, for full transparency.
Important: our figures are estimates with a range, derived from public life-cycle studies and the sources below. They are explicitly not certified measurements of a specific item. The actual saving depends on how you use a product and on what you replace. See also our methodology and terms of use.
General method & life-cycle assessment (LCA)
The basis under every CO2 comparison: how you measure a product's impact across its whole life (raw material, production, transport, use, waste).
- European Commission, Environmental Footprint & JRC ↗The official EU method for measuring a product's environmental footprint.
- ecoinvent ↗One of the largest international life-cycle inventory databases.
- IPCC (Intergovernmental Panel on Climate Change) ↗The UN climate panel; source data on greenhouse gases and warming factors.
- Our World in Data ↗Public, well-referenced datasets on environmental impact.
Price & saving (true pricing)
Alongside a CO2 saving, some products also show an indicative euro amount for avoided environmental costs, and a tangible comparison (car kilometres, a tree's CO2 uptake). The euro figure is not a shop price, it's a societal cost estimate.
- CE Delft, Environmental Prices Handbook 2023 ↗The official Dutch shadow price for CO2: €0.13 per kg CO2-eq. (central estimate, range €0.05-€0.16, 2021 price level). We use the central estimate from Table 1 (p.6) and Table 2 (p.7).
- CBS (Statistics Netherlands), CO2 emissions from road traffic in 2022 ↗Total CO2 emissions from Dutch passenger cars in 2022: 15.3 billion kg.
- CBS, Motor vehicles drove 7 percent more in 2022 ↗Total distance driven by Dutch passenger cars in 2022: 114.31 billion km. Combined with the figure above (same year, same vehicle category), we calculate an average of ≈134 grams of CO2 per kilometre for the whole driving fleet, not just new cars.
- Staatsbosbeheer (Dutch national forestry service), Forest and CO2 ↗A free-standing tree absorbs on average 10 to 40 kg of CO2 per year. We use the midpoint of that range (25 kg/year).
Food
For claims about plant-based alternatives, meat substitutes and food waste.
- Poore & Nemecek (2018), Science ↗The most cited global study on the environmental impact of food.
- Milieu Centraal ↗Independent Dutch guidance on, among other things, the footprint of food.
- WRAP ↗Research on food waste and the circular economy.
Clothing & textiles
For claims about cotton, recycled fibres, second-hand and fast fashion.
- Ellen MacArthur Foundation ↗Leading research on circular fashion and textile impact.
- European Environment Agency, textiles ↗European figures on the environmental and climate impact of textiles.
Electronics & appliances
For claims about refurbished devices, longer use and energy consumption.
- International Energy Agency (IEA) ↗Global data on energy use and the emissions of electricity.
- RIVM ↗Dutch research institute; life-cycle and environmental data.
- CE Delft ↗Independent research consultancy for environment and energy.
Spotted something we can improve?
We keep this list current on purpose. If you see a claim you can back up, or debunk, with a better source, let us know via the newsletter page. Corrections only make the list stronger.