How Is the Carbon Footprint Calculated?
Estimating the Carbon Intensity for a Particular Item
Certain retailers publish a Economic Input-Output Life Cycle Assessment (EIO LCA) that attempts to account for the carbon emissions incurred in creating an item. The assessment generally include estimates of the carbon intensity for the following activities:
- Production of all inputs (from the raw materials to the final product)
- Transportation for all inputs as well as delivery to the customer
- Packaging for the final product
- Electricity for running the retailer (from keeping the lights on at physical stores to the electricity used by servers to process the sale)
It should be noted, this is an estimate and cannot fully account for all emissions attributable to the production of an item. At this time the EIO LCA model is most widely used, but Carbon Calculator is open to adopting new methodologies. If you have a concern about accuracy, feel free to raise an issue on GitHub: GitHub Issues
Estimating the Carbon Intensity for a Retailer
After computing the estimate of emissions for all items sold, an aggregate metric can be computed for the retailer: the estimated carbon released per dollar of revenue. Some companies (e.g. Amazon) provide this directly while others do not go this far and Carbon Calculator uses SEC reports to calculate this figure.
Carbon Calculator currently supports the following retailers:
- Amazon.com Amazon September 2019 EIO LCA Report
If you know of a retailer that isn't supported on the list above but is publishing carbon footprint metrics, create an issue here: GitHub Issues