How sustainable are fashion resale platforms?

How resale quantifies its environmental contribution using Life Cycle Assessment (LCA).

Have you heard that whole pitch about sustainability in fashion? Do you have a strange affinity with numbers and have you consequently wondered how sustainability can be quantified? Or maybe (more probably, in fact) you are exploring ways to make your life more environmentally sustainable and buying second-hand designer clothing feels like a good way to achieve that? You’re on the right track, and this article explores why that is the case and how the numbers add up. 

In the mystery world of sustainability-related acronyms, one has been gaining significant recognition over the past decade: LCA, life cycle assessment. In humanity’s quest to accurately quantify the environmental impacts of our activities, LCA has emerged as one of the key methods for assessing the material flows associated with the production of products or services and linking them to environmental impacts (such as climate change, acidification, eutrophication, ozone depletion and so on). 

As fashion is known to be one of the most polluting industries worldwide, it is no surprise that LCA found its place at the table among apparel designers, fabric producers, fashion marketers and (re)sellers. In itself, LCA can be a highly technical topic, but businesses across the globe are trying to churn out ever newer and ever simpler ways of communicating it at a dazzling rate. This post explores how the metrics presented by some of the largest players in the clothing consignment business compare to one another and how you, a user of these platforms, can better interpret the LCA-based information bestowed upon you.

First, let’s go over the ingredient list of what it takes to cook up a life cycle assessment study:

• Scope of the study: which products/services are we looking at (for example clothing, accessories, footwear).

• Goal of the study: what are we trying to achieve, aimed at what target audience (convey the environmental benefits of buying resale versus new to the user of a resale platform).

• Functional unit: what do the numbers relate to i.e. environmental impact per unit of…mass, volume, one piece of product, or the function performed.

• System boundaries: which life cycle stages are included i.e.extraction of raw materials, processing into the final product, distribution, use, end-of-life in the form of disposal/recycling/reuse of material.

• Impact assessment categories: which environmental impacts do we measure (e.g. climate change, resource use, water consumption) and which method should be used to quantify them.

• Data collection: what information is available about our system (e.g. actual consumption figures, estimates, proxy values, industry averages, life cycle inventory datasets) – where do we get it from and what is its quality.

• Key assumptions: data coverage is never 100% accurate, so informed estimates need to be made – some of them can crucially affect the outcome of the study .

• Excluded information: some aspects of the system can be excluded from the assessment due to large uncertainties or irrelevance to the goal; some inputs to the system can be considered small enough to be negligible

•  Pluuuus some smaller things and considerations that can be unique to the specific study. 

Now let us return to the companies in focus. As a true consignment fiend, you will already be familiar with Vestiaire Collective, TheRealReal, Vinted and ThredUp. All of them publish sustainability information based on LCA, and use it as an additional value proposition for their customers and investors (and the wider public, of course). There are however differences in the approaches they use, how much information they disclose, and how it’s communicated. The table below details different attributes across the four selected resellers, but to keep things simple, let’s limit ourselves to three aspects of their results.

1)    The Vestiaire Collective (VC): the avoided environmental impact per VC’s product category is one of the indicators published in the 2024 Circularity report

2)    The RealReal (TRR): the avoided environmental impact is scaled up to the specific weight of individual products listed and integrated into the shopping interface 

3)    Vinted: the avoided climate impact is calculated per average second-hand item and published in the Climate Impact Report (2023)

4)    ThredUp: the environmental footprint and avoided environmental impact is calculated per 1 average use of a garment and published in an LCA report (2022); the numbers are also available in the shopping interface

Equally briefly, the three focus areas to discuss will be: 

1)    Communication to the platform user

2)    Use of a displacement rate

3)    Identification of the biggest positives, negatives and unknowns

1)    Communication to the platform user

How is information communicated?

Vestiaire Collective and Vinted are keeping it conventional by issuing reports. The one made by VC is however much more general (as it covers the entire circularity strategy of the business, not only LCA data), and no in-depth LCA report is available that would detail how the LCA-based numbers came into existence. This is unfortunately not unusual in the corporate landscape, where information is money (and LCA reports do reveal a lot of supply-chain specific data), though it is always disappointing. On the other hand, Vinted has published a much more comprehensive report that details how they collected the primary data and how all the assumptions come together. This is definitely an example of good practice. 

 On the other hand, both TRR’s and Thredup’s reporting is more dynamic and user-friendly. Both integrate the (avoided) environmental impact into the shopping experience by displaying the environmental savings a shopper is making by choosing a second-hand garment. This is a good approach for making the consumer aware of more than just the monetary price tag, however TRR lacks in-depth information about their methodology and how the information was conceived in the first place (no report available that would document all the methodological choices and assumptions made!). ThredUp, however, clearly invested heavily in their work, as they have both the shopping interface-integrated numbers and a very comprehensive stand-alone report. ThumbsUp!

What is communicated? 

Vinted and TRR communicate the environmental benefits of shopping second-hand in kilograms of carbon dioxide saved, whereas TRR does so with liters of water instead. VC and ThredUp convert these carbon savings into something more ‘tangible’, such as the avoided kilometres of driving a car or hours of powering an LED bulb. As someone working with LCA on a daily basis, either doing both or exclusively sticking to the scientific data is preferred, because it improves transparency and comparability, while reducing the possibilities of greenwashing. On the other hand, scientific ‘translations’ can be used to fool laymen with comparisons that sound good but obfuscate the message and comparability of the calculated numbers across different studies.

2)    Use of a displacement rate

In an ideal world, buying a second-hand garment would prevent a person from buying a newly made piece. Theoretically, this would mean that the two items are completely substitutable, and in LCAs studied here this is referred to as displacement rate. For each piece of clothing bought second-hand a production of one new garment is avoided – which is naturally beneficial in environmental terms. However, this relationship is not always the same. If people shop impulsively, the lower price of resale items drives additional demand, or even if buying second-hand assuages some of the shopping guilt one would experience otherwise. This could mean that people buy two second-hand pairs of jeans instead of one pair that is newly produced, resulting in a displacement rate of 50%. This is a key assumption in the LCA studies done by the resale companies, especially as they use different displacement rates based on a variety of sources: calculated data from surveys, external literature, or just hypothetical assumptions. The higher the displacement rate, the more favourable for the environment buying second-hand will be. Unfortunately, there is a broad range of values used and calculating it is not exactly hard science. 

Vestiaire Collective estimated a displacement rate of 79% based on a consumer study of 13,400 submissions (sending a questionnaire to their customers and asking them if purchasing an item on VC has prevented them from buying a newly produced equivalent), whilst TRR estimated a displacement rate of 33% based on an external report by Worldwide Responsible Accredited Production. Since TRR and VC serve a similar pool of customers and focus exclusively on designer clothing, this is an interesting methodological choice to compare. Though TRR do emphasise that they picked 33% to be on a conservative side (good practice in LCA), it would be interesting to know what kind of a displacement rate they would get if they used the same customer survey as the one used by VC. For resellers that do not focus exclusively on designer goods, Vinted assumes a displacement rate of 39% - which is also based on a customer survey with a sample pool of 108,829 respondents. Finally, ThredUp, though also based on customer surveys, calculated slightly different displacement rates depending on the product category in question. These range between 70-80% across all fifteen product categories. They also tested the lowest displacement rate possible that would theoretically allow second-hand consumption to remain more environmentally beneficial than the alternative.

While having primary data from consumers is beneficial, consumers tend to misestimate their shopping habits, which is hard to avoid. Since a difference between 33% and 79% results in a 239% increase, the reported environmental results per item of clothing will naturally differ too if a resale jacket with a displacement rate of 33% results in 1 kg of avoided carbon dioxide emissions, a displacement rate of 79% would increase that to 2,39 kg. In other words, the leniency in the methodologies used by these companies is the most important factor in the numbers reported. See what I mean by saying that this is an important decision to make? This does not mean that using a high displacement rate is bad – if the number accurately reflects consumer behaviour then yay for the resale space, all the more reason to highlight its inherent environmental sustainability. but if the number is associated with a lot of uncertainty and variability, using a more conservative assumption might give a more realistic result.

3)    Identification of the biggest positives, negatives and unknowns

Vestiaire Collective:

• Biggest positives: They have included the emissions from VC’s own operations (e.g. online listing and purchase, warehouse and packaging processes, shipping the package) while calculating their entire organisation’s carbon footprint according to the Greenhouse Gas Protocol and committed to reducing it in line with Science-Based Targets Initiative (working with these two frameworks is usually a decent sign that at least on the surface, the company cares about sustainability)

• Biggest negatives: no complete LCA report published!

• Biggest unknowns: since there is no LCA report, it is unclear what other assumptions and exclusions were made.

 

TheRealReal:

• Biggest positives: integration into the shopping interface, values modified in accordance with the specific item listed (though only based on weight of the item!). they also included a stakeholder review of the TRR calculator developed.

• Biggest negatives: the study has a narrower scope and no detailed report is available. 

• Biggest unknowns: unclear if emissions generated due to TheRealReal’s activities are included – they seem to be excluded

 

Vinted:

• Biggest positives: included insights into how the climate impact of resale operations differs if items are delivered to a customer’s home versus to a pick-up/drop-off point; differences in using new or reused packaging for transporting the items; organisational carbon footprint according to the Greenhouse Gas Protocol + committed to reducing it in line with Science-Based Targets Initiative.

• Biggest negatives: only one environmental impact category considered (climate change – avoided emissions of CO2eq), did not include the operation emissions from distribution centres due to data gaps.

• Biggest unknowns: which life cycle inventory database are calculations based on – though otherwise a very solid study!

 

ThredUp:

• Biggest positives: Integration into the shopping interface. they also consider the use stage of garments – the emissions caused by laundering and repairing the clothes. Insights into consumer behaviour and how many wears customers get out of new vs. resale items, 9 environmental impact categories considered, a very comprehensive report PLUS the study was critically reviewed by a third-party

• Biggest negatives: the report is somewhat hard to read as it is very dense?

• Biggest unknowns: no further questions, your honour!

 

All in all, there are still a lot of subjective choices LCA experts need to make when designing and communicating LCA studies, and the data we have available is never 100% complete and realistic. We are learning every day and there are significant efforts being made to standardise the LCA space to ensure that the end information is more comparable, transparent and accurate, so despite certain shortcomings of the LCA studies discussed above, I am really happy to see more companies engaging with LCA and sustainability in general. Of course, conducting an LCA is no stamp of approval, it only quantifies a product/company’s impacts, but in doing so, it informs which processes or materials need to be improved and provides talking points for actionable objectives.  

And as for you, apparel consumers: though the LCA space unanimously agrees on the fact that no purchase is still better than any type of purchase, shopping second-hand does come with environmental benefits, so keep doing your thing, take good care of your clothes and spread the message to your friends one pre-loved garment at a time.  

Written by: Martina Fridl