Impacts through the lifecycle of a product

Highlighting how aspects of footwear design, construction, distribution, use and disposal can have significant effects on the environment.

by Nicola Pichel-Juan

Reducing the environmental impacts of footwear products and their supply chains will be fundamental to all organisations within the footwear sector in the coming years. While much the focus to date has been on the development and sourcing of sustainable materials (which of course is vital), impacts can occur at all stages in the life of a shoe – from its design through to the end of its life. This article will highlight some key areas for consideration for the design, development, production, distribution, use, and ultimate disposal of footwear in order to minimise its impacts.

Design and development

The design and development phase is arguably the single most important part of the lifecycle. Decisions made during this aspect of the project will to a large extent determine the product’s impacts throughout the rest of its life. Material selection – both in terms of the material itself and from where it is sourced – is crucial. If a material with a lower environmental impact is chosen, it must still meet the performance requirements for its intended application. Durability should also be considered, as a product that is built to last will have a lower environmental impact per wear or use over the course of its life.

Reengineering a product to reduce its weight will also lower the impacts of the materials used, as well as the effects of transporting the materials and the finished product, However, this may not always be possible, either for performance demands – for example, with industrial footwear requiring a protective toe cap or midsole, or for design reasons.

Increasingly at this stage, designers and product developers are looking ahead to the end of the product’s life and considering how it should be (or is likely to be) disposed of. This can lead to the selection of materials that can be recycled, a reduction in the number of different materials or components used, and careful consideration of how the shoe could be disassembled into its constituent parts.

The sampling process will typically have a high impact. This comes from the manufacturing of the samples themselves and from shipping them to destinations all around the world – typically by air freight, which has a global warming impact that is around 50 times greater than shipping by sea. The application of modern design packages that can create high quality three-dimensional (3D) visualisations could support a reduction in the number of sample iterations of a particular product that need to be made.

Sometimes multiple rounds of samples also need to be made to achieve the desired fit for a particular product. The use of technology such as SATRA’s 3D-printed fitting aids and Digital Last Assessment service can help, as they are ideal supports to in-factory fit evaluations, thus giving increased confidence that any samples which are being shipped will fit as well as expected.

Further opportunities to minimise the impact of air-freighting samples include investigating if the amount of packaging used can be reduced, or if the samples can be made closer to market.

Materials

The single biggest impact during the lifecycle of a footwear product that will be identified from a carbon footprint analysis is likely to come from the materials and components used. There is no single criterion or definition for a ‘sustainable’ material. Considerations include, for example, whether or not it needs to be bio-based, be manufactured with recycled content, or be recyclable at the end of the product’s life.

Compromises often have to be made, as it is unlikely that a material will meet every sustainability criterion. For instance, natural rubber and leather have both been linked to deforestation. However, they are durable, natural materials that do not lead to additional fossil fuels being extracted and consumed. There are also examples of materials marketed as ‘bio-based’ that repurpose an existing waste stream (often from the food industry) which have been blended with plastic or have a plastic backer applied to enable them to exhibit sufficient strength.

Impacts will also vary between manufacturers of the same type of item. A leather produced in a tannery working to high environmental standards that has improved its energy and water efficiency, reduced effluent discharges, and can demonstrate that the hides it uses are not linked to deforestation will have a much lower environmental impact than a tannery which does not operate to the same standards.

The wider supply chain is also important. It is pointless to identify a material with a lower environmental impact if that material then must be flown around the world in order to meet production deadlines.

Production and supply

A considerable amount of activity that has traditionally been undertaken in footwear factories for cost-saving purposes – such as optimising material use and minimising waste – will also reduce environmental impacts. A key area of focus should be to engineer upper patterns for cutting efficiency and then to ensure that the cutting process itself is carried out as efficiently as possible. SATRA’s SATRASumm software package can support with this and can typically reduce material consumption by 4 to 8 per cent, with a corresponding reduction in material costs and environmental impacts.

It is inevitable that some waste will still be generated throughout the production process. Identifying the different waste streams and the optimal way to repurpose, recycle or dispose of each of them is another way to reduce the overall production impact.

The use of 3D printing opens up new opportunities that could allow footwear to be made closer to market and potentially even made to order for an individual consumer. This in turn would minimise waste and the risk of over-production.

For cemented footwear, a transition from solvent-based adhesives that release harmful ‘volatile organic compounds’ (VOCs) into the atmosphere to water-based adhesives will also benefit the environment, the health of production workers and typically reduce costs.

The energy efficiency of manufacturing sites should also be considered, as this can also lead to cost savings at a time when energy prices have escalated in many parts of the world. Generating electricity on-site through renewable sources such as solar panels is ideal. However, even more simple and lower-cost measures such as the installation of energy-efficient equipment, correctly maintaining existing equipment, not leaving machinery switched on when not in use, the installation of LED lighting and reviewing practices for heating and cooling of production areas, can give substantial reductions.

The destruction of unwanted and unsold products is a huge source of environmental impacts in the fashion sector. In fact, it is estimated that 40 per cent of all fashion items being produced are sold at a markdown or destroyed. The modern consumer is used to everything being available on demand, with next-day delivery services from e-commerce sites being commonplace.

In order to fulfil this demand and to minimise the risk of lost sales, there can be a tendency to over-stock and therefore over-produce. This is where a greater focus on improving forecasting and stock management processes is crucial, although it is undoubtedly not an easy problem to solve. Nevertheless, a change in approach is likely to be required, as the European Union is intending to outlaw the destruction of unsold textile items.

Distribution and sale

When considering environmental impacts that could be incurred in getting footwear from the point of manufacture to the end consumer, the most important factor is the freight method used. This is specifically the avoidance of air freight, which is not only costly from a financial perspective, but also in terms of the environmental impacts incurred.

Sea freight has a very low impact – in fact, it is lower than transporting goods by road. Therefore, a typical distribution model of manufacturing sites based in Asia shipping by sea to Western countries does not incur a big impact from transportation, and this impact is likely to decrease even further as the adoption of biofuels increases. ‘On-shoring’ of production (locating business operations or manufacturing processes within the same national borders as the company’s home base) or ‘near-shoring’ (relocating operations to a nearby country or region which often has lower labour costs) could therefore in some cases increase the overall impact of a product as low impact sea shipping is replaced with higher impact road transportation.

CO2e emissions for different forms of freight transportation
Freight method	Kg CO2e impact per tonne transported 1 km
Sea (container ship 8,000+TEU)	0.01266
Road (diesel HGV >3.5 to 33 t)	0.61562
Air (long-haul freight flight to or from the UK)	1.099032
CO2e is a measure used for the warming potential of all greenhouse gases using carbon dioxide as a baseline. For example, over a period of 100 years, 1 kg of methane has a CO2e of 28, because over those 100 years its warming effect is 28 times higher than that of carbon dioxide.

Efficient packaging of finished goods for shipment can also be used to reduce costs and environmental impacts. this can potentially be achieved through selecting a more appropriate box size or through reengineering the shoe box itself to consume less cardboard. There is also a growing trend towards using shoe boxes that can be repurposed as shipping boxes to fulfil e-commerce transactions. The initial cost of the box may be higher, but overall costs and emissions will be lower.

While there are many different finish options available today to create striking and appealing shoe boxes, many of these options will have a higher impact due to increased consumption of inks and other consumables. A more simple box which carries less printing is better for the environment, and the use of alternative inks (such as the soy variety) are also becoming commonplace in the industry.

Emissions associated with any retail stores under the organisation’s operational control will need to be factored in. This will include areas such as energy efficiency, energy sourcing and the footprint of any fixtures and fittings in the stores. Transporting goods to individual stores or e-commerce shipments from distribution centres to consumers must also be taken into account, with the relative impacts of different freight methods already having been previously discussed in this article.

Product use

The most important factor that will determine a shoe’s overall impact during its use phase is how long it lasts. It is increasingly recognised that the impacts of an item should be in some way divided by how many times it can be used or worn. As well as engineering and testing a product to ensure that it is robust and not likely to fail prematurely, it is also important to understand how comfortable it is, if that comfort can be maintained throughout its life, if the product can be repaired and if its appearance can be maintained. SATRA can support its members with testing and research projects to understand all these elements.

As consumers become increasingly aware of the importance of a more sustainable lifestyle, there is a growing trend for cleaning and refurbishing products. This may be performed by the consumers themselves or through dedicated schemes, often provided by a brand or retailer in partnership with a dedicated repair company. It is also important to consider the impacts of any shoe cleaning products that are sold or recommended. Where practical, it is recommended to transition from solvent-based products to water-based alternatives and to use pump dispensers rather than aerosols.

While the shoe itself may be expected to have a lower impact in wear than an item of clothing that will be washed multiple times (incurring impacts from electricity, water and detergent), there will be a small impact from any cleaning products that are used. Another area that is also now being investigated is the potential for microplastics to shed from footwear, particularly outsoles, during wear and how this potential impact can be measured and then understood (see the article ‘Microplastics in footwear and clothing’.

End-of-life

Eventually all footwear will reach a point where it is no longer viable to wear or repair. Globally, around 25 billion pairs of footwear are produced annually, and it is estimated that currently 85 to 95 per cent of them will be disposed of via landfill or incineration. Footwear is difficult to recycle, typically being made of many different materials and components that are stitched or glued together, and which are not intended to easily come apart. It is extremely difficult to disassemble the footwear into its constituent parts, and the technology and infrastructure to do this at scale has for many years simply not existed.

This is now starting to change. An article in the 2024 SATRA Bulletin Sustainability Special introduces a new recycling facility in the Netherlands which is capable of processing up to 2,500 pairs of shoes per hour, and then separating the shoe out into different material streams that can be either recycled or repurposed.

Another option is ‘compostability’, which is increasingly being considered as a sustainable end-of-life. A number of footwear brands are actively working on the development of compostable footwear or shoes that when placed into a particular environment will not cause any harm, even if they do not break down quickly enough to meet the requirements of existing compostability specifications.

Other companies are setting up dedicated schemes to take their footwear back, shred it and use the resulting material as an input to manufacture new materials and components.

It is therefore important to consider during the design process where a shoe may end up at the end of its life, what impact it will have there, and if a more circular approach is viable.

Summing up

Over the course of this article, an overview has been provided of the most likely causes of environmental impacts throughout the footwear product lifecycle and what actions can be taken in order to mitigate them.

Publishing Data

This article was originally published on page 18 of the May 2024 issue of SATRA Bulletin.

Other articles from this issue »

---