At Sellpy, we want to inspire everyone to lead sustainable lives. By creating awareness of how our daily decisions affect the climate and by inspiring people to change our behaviour, we want to help more people to consume and live sustainably.
What assumptions has Sellpy made when calculating CO2 savings?
By carbon dioxide savings we mean the amount of greenhouse gases or carbon dioxide equivalents (CO2e) in kilos that are used to produce new goods. Buying second hand instead of new leads to a reduced need for new production and thus reduced greenhouse gas emissions.
To estimate the carbon dioxide savings, we have made some assumptions based on a number of different sources. We collect data about the materials that the clothes we handle are made up of. Based on this, we have made assumptions about the mixture of materials that each item is made up of in order to obtain an average measure of the carbon dioxide savings per item.
An example of a calculation
About 75% of all sweaters we handle are made up of 100% cotton and the other 25% are made up of 100% wool. By weighting these measurements, we get an average for the textiles that sweaters consist of, i.e. 75% cotton and 25% wool. We use the product's estimated weight and average CO2 requirement to produce the textiles to estimate the kilos of CO2 emitted to produce 1 kg of each garment.
Simplified, this means: More material + greater weight = larger CO2e footprint.
What sources have we used?
We have based our assumptions on a number of different sources:
Environmental assessment of Swedish clothing consumption - six garments, sustainable futures by Gustav Sandin, Sandra Roos, Björn Spak, Bahareh Zamani and Greg Peters, 2019.
Climate data for textiles, Sandra Roos and Mikael Larsson, 2018.
HIGG MSI, Materials Sustainability Index.
CleanMetrics, CarbonScopeData LCI database.
Data from H&M
The Higg MSI and why we use it
The Higg MSI is a tool that can be used as a basis to calculate the environmental impacts of materials in a variety of consumer goods. At Sellpy we use the Higg MSI to obtain emissions factors to calculate the emissions for the production of the raw materials, yarn and fabric. We then apply sustainability data from the H&M to include post production activities. The savings data presented to our customers with regards to CO2 and water savings also include internal data such as weight and material composition.
Although we currently use data from the Higg MSI to highlight the environmental benefits of choosing second hand over newly produced items, we remain mindful that no tool is perfect. Collective and continuous work is needed to advance existing data with better accuracy and detail. We welcome any and all efforts in that direction.