Knowledge Hub > Sustainability > Carbon footprint estimates

Carbon footprint estimates

Learn how Sourceful calculates the carbon footprint estimate for all possible configurations of live products in our Shop.

Last updated: Mar 18th, 2022

What is a carbon footprint estimate?

A carbon footprint is an estimate of a product’s environmental footprint. Carbon footprint estimates are expressed as a carbon dioxide equivalent (CO2e), a unit of measurement which represents all major greenhouse gases. In doing so, CO2e indicates a product’s total global warming potential.

We choose to account for the entire life cycle of a product, which means we estimate everything from material extraction, to production and final disposal. This is what’s called a cradle-to-grave analysis (excluding transport to the final consumer). This is also why the process of measuring a carbon footprint estimate is often referred to as a Life Cycle Assessment (LCA).

Note: A product’s effect on climate change is often equated to its environmental impact. But products can have other harmful effects on the environment, such as chemicals from manufacturing leaching into water supplies. These effects aren’t captured by carbon footprint estimates.

How to use CO2e data

What contributes to a product’s carbon footprint?

How do Sourceful estimate these carbon footprints?

We work with each supplier to build a carbon footprint model for their specific product and for all the variants available for that product on our platform. For mailer box and shipping box, for example, there are billions of variants, whilst for tapes there are hundreds.

For each component, we combine manufacturer information with data from established impact databases such as ecoinvent and the UK government GHG Conversion factors for company reporting. Examples include the typical emissions of a container ship or the typical emissions for each individual chemical component of an ink.

This information is used to build the parametrised model, which we then share with each manufacturer so they can sign-off all assumptions and datasets. This is to ensure that what we’ve built is a reliable representation of their product.

Our Life Cycle Assessment method is verified to ISO 14040 and 14044 standards and represents a best efforts cradle-to-grave (excluding transport to the end customer) carbon footprint estimate.

Learn more about the ISO independent critical review of our methodology here.

Where do you get your data from?

Sourceful’s Impact Engine leverages data from a range of sources, depending on what is needed. The majority of our emission factors come from ecoinvent (cut-off system model), whilst the majority of our end of life allocations come from UK Government (DEFRA) statistics on UK waste disposal. And the majority of our transport emission factors come from UK government GHG Conversion factors for company reporting.

The information on materials, manufacturing processes, locations and transport types is all provided by and signed-off by our individual suppliers.

Our calculations approach is based on the Environmental Footprint (EF) 3.0 method, an initiative of the European Commission. The data we publish is for the Global Warming Potential (CO2e) impact category.

How is your relative performance scale calculated?

Viewing a carbon footprint number in isolation makes it difficult to understand how well you’re doing. That’s why we’ve designed a scale to show you where your current configuration ranks against other possible configurations.

Mailer box is a good example to illustrate how this scale was calculated. We took a sample of 15,000 mailer box configurations, all with different attribute choices and order quantities, and put these into four size buckets.

We then estimated the carbon footprint for each and used this information to identify the distribution within each size bucket. To make this a relevant comparison, we normalised each box to measure impact (CO2e) per metre-cubed of volume.

By doing this, we can then place any configuration you build in one of these buckets. And we can show how it ranks within that bucket, based on its normalised (impact per metre-cubed) score. Finally, based on the distribution of results within that bucket, we can tell you what percentage of boxes your configuration is lower than.

How are these benchmarks calculated?

Why trust this data?

Why do carbon footprint estimates matter?

Known limitations to Sourceful's methodology

  • Our CO2e impact data is intended to act as a best-efforts estimation of a product’s carbon footprint (CO2e). A best-efforts estimate is designed to represent a reasonable estimate of the product’s carbon footprint, based on a consistent LCA process. As in the case of any LCA, the estimate may not always reflect reality.
  • Our CO2e impact data reflects to our best knowledge an estimate of the impacts, based on a consistent ISO-conformant Life Cycle Assessment methodology. Data inputs and assumptions have been reviewed with each manufacturer to confirm that the modelling choices are representative. Whilst we validate this information for robustness and plausibility using certifications or third-party data sources (such as industry average data), this is subject to potential error.
  • The methodology is designed to report Global Warming Potential (GWP) estimates on the Sourceful platform. Please note that carbon footprint is a common indicator of a product’s environmental footprint, but climate change is not the only type of impact that affects the environmental impact of a product.
  • The locations and behaviours of the final customer of our products are not known, given we supply first to businesses. This is an inherent limitation of our business model. As a result, the transport of the packaging to the end consumer is omitted. To mitigate the uncertainty on the final customer location, we made a simplifying assumption that the customer is UK-based. And so we’re able to estimate end of life from standard UK assumptions on disposal.

This is not an exhaustive list of limitations.