24.3 billion shoes were produced world wide in 2019
With 7.8 billion people in this world, that is roughly 3 shoes per person. This varies based on location and income with some purchasing 6 pairs per year or more. Sneakers are really seen as fast fashion with new styles being released every day. In this way of thinking, sneakers are acquired and disposed of with not much thought. They are also not designed to last, with the sole wearing out or the upper coming apart while the rest of the shoe is still good.
Can a sneaker be designed in such a way that parts can be repaired or replaced rather than disposing of the entire shoe?
This capstone project aims to answer this question by investigating the materials and construction methods used in the sneaker industry and asking ‘why?’
Sources: ‘24.3 billion shoes’: World Footwear (2020) / ‘7.8 billion people’: Worldometers (2020) / ‘6 pairs per year’: Rahimifard et. al. (2007)
Problem Overview
With so many shoes being produced and purchased each year, a lot of old shoes are disposed of. Most shoes were not designed to be taken apart, repaired or recycled so instead they become waste.
Top Consumers
The top five consumers of shoes per capita. The US has the most with 6.9 pairs per year.
Adapted from Rahimifard et. al. (2007), original source: SATRA (2003)
“…the fast-fashion model encourages consumers to view their fashion items as disposable and hence consumers become more detached from these products.”
– Bick et al. (2018)
Shoes To Landfill
With 300 million shoes disposed of each year in the US alone, it is estimated that 80% or more of all shoes end up in landfill
US Department of the Interior
Environmental Impact
The footwear industry is negatively impacting the environment and contributing a vast amount of CO2 emissions that accelerate global warming. Raw material extraction and sourcing along with the manufacturing process are where most of the impact occurs.
The graph below shows what percentage of the negative environmental impact is caused by which stage in a shoe’s life cycle. Raw material extraction has the largest impact to our ecosystems while manufacturing has the most impact towards climate change.
Life Cycle Impact
Each material type also has a list of pollutants associated with it. These negatively impact air and water quality as well as human health.
From this information we can also determine the relative impact of different types of shoes based on their materials. Leather and synthetics have near equal total impact while leather alone has the highest impact in one area, and that is ecosystem quality with 82% of the total.
Impact By Material Type
CO2e Per Shoe
CO2e (Carbon Dioxide Equivalent) is a measure of the amount of carbon that is emitted into the atmosphere by a process. An LCA (life cycle assessment) can help to calculate these values by determining how much carbon is produced from each material in a product and at each stage of the products life. These values can be used to see a products impact on rising global temperatures.
CO2e From Sneakers
Not all companies publish their product’s CO2e information however here are a few examples from Nike and Allbirds. The estimated average for a ‘common’ sneaker is 14 kg CO2e.
Source data from: Nike (2019), Allbirds (2020)
If The Footwear Industry Was A Country
14 kg CO2e per shoe doesn’t sound like a lot. When that is multiplied by the number of shoes produced however, the footwear industry would be the 17th largest polluter of greenhouse gases.
Adapted from McLoughlin (2020). Country data source: Union of Concerned Scientists (2020)
Sustainable Alternatives
The majority of sneakers in the marketplace are not designed to be sustainable or eco-friendly. Of the ones that are, the focus has been on using sustainable materials that have less of an impact, or trying to make the shoe recyclable at its end of life.
Eco Traits
To make the eco shoes more sustainable, most have a reused or recycled material and it’s most often recycled plastic. The data above is based on the 2556 shoes in the RunRepeat database, of which only 89 are ‘eco-friendly’.
Adapted from RunRepeat – McLoughlin (2020)
Impact Of A Sustainable Upper
A shoes upper accounts for 41% of its material emissions. Using a sustainable material would only affect the CO2e from the materials contribution to the total output. If an average shoes has 4 kg CO2e from this area, a recycled material could only affect up to 1.6 kg CO2e.
Cheah et. al. (2013). MIT Study
Summary
The use of sustainable materials is beneficial to the environment as it reduces the impacts of producing raw materials and the pollution it creates. This does not however have a significant impact to the total CO2e from a sneaker’s life cycle and does not reduce the number of shoes being produced, purchased and disposed of. This is the main issue. Shoes need to last longer so that fewer need to be produced. A sneaker could last longer by increasing the durability and longevity of the original product or by making it repairable to prolong its life.
Next Steps
To move forward with this project I have identified three possible pathways. These are not resolved solutions or refined concepts at this point. They are directions I can research further to ultimately end up at a concept to be proposed in December.
Path One
A completely modular sneaker where each piece can be separated to be repaired or replaced. Each component would be just one material so they can be recycled more easily. Modularity allows for customization which can help increase personal attachment and discourage disposal.
Path Two
A sneaker designed around production efficiency where the goal is zero waste. The patterns, molds and processes could be optimized so that there is no excess material being created.
Path Three
Designing a sneaker to be the most robust and wear resistant as possible so that it does not wear out for several years. High wear areas of the shoe are reinforced and multilayered for longevity.
I would appreciate any constructive feedback or insights that would assist me in the process. It would be helpful to learn if my research was clear, easily understood, and if there are recommendations to move forward.
Please feel free to email me at mikeclarkedesign@gmail.com to discuss the topic in more detail
Sources
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