At some point in everyone’s life, it is highly likely that one might own some object made with a fabric we call leather. It may be a sofa, bag, jacket, shoes, car seats, or a cushion. It is a loaded topic for various reasons and here we explore the topic in some detail. We have looked at the use of leather for interior uses during our efforts to reduce environmental impacts in our own design specifications.
Animal based ‘leather’ is the one we are starting from, and as a very quick introduction to why it is a thorny environmental issue, the main negative impacts related to its use tend to come from:
- Animal farming carbon footprint, land use ecology impacts, and deforestation
- Leather processing embodied carbon emissions
- Leather process toxicity and impacts to ecology and workers during the process
We should also present the added value of this type of fabric; it is used when durability is needed. It does last a long time but not necessarily longer than other newly engineered fabrics these days.
Background
Over the years, in conversations with the leather or food (meat) industries, we get told that the leather industry is only using the material as it is a byproduct of the meat industry, and the meat industry is using the meat as it is a byproduct of the leather industry… According to The Drawdown reports[1], and one delving into a holistic view of land use, food security and nutrition, the weight stacks up against meat and animal production at current levels. If a plant-based diet was introduced to half of the global population, it could reduce global GHG emissions by at least 54 Gigatonnes from 2020 to 2050.
“If 50–75 percent of people adopt a healthy diet of an average 2,300 calories per day and reduce meat consumption overall, we estimate at least 54.19–78.48 gigatons of emissions could be avoided from dietary change alone. Since agriculture, particularly for cattle and animal feed production, is the leading driver of tropical deforestation, reducing meat consumption can avoid additional forest loss and associated greenhouse gas emissions.”
Peta UK stats show that 1 billion animals [2]are killed every year to produce leather that we see in stores, aeroplanes, cars, restaurants, hotels, and our homes etc. Animal leather is increasingly in high demand (is it a status symbol?), which will only escalate as a problem as population expands. As a caveat to this post, we are not reflecting on the ethical issue of killing another living creature, which we know in many cases has a higher priority in specification but recognise it’s importance for many clients and other designers.
Diving into the detail
To understand if the choice of animal leather and if or when it is sustainable, we need to look at the data for specific locations, use types and do whole life cycle thinking. For example, if we based a decision on only the Drawdown data and not looked at the impact alternative solutions could offer, we may fall into unintended consequences.
It is understandable that animal leather is highly durable with a life span of 15+ years, depending on how it has been taken care of and its daily wear and tear. This feature makes it an ideal option for many projects and locations where high intensity use and a long-life cycle is planned in.
Does this make it good leather, however?
This debate between animal leathers and plastic leathers for example has been around for many years, but neither option can be clearly described as good due to chemicals that are used, all for justified durability or occupant health drivers. A highly impacting factor is the process of leather chroming which is the tanning of the leather using a solution of chemicals, acids, salts etc and then creating toxic wastewater leftovers. Chrome tanned leather reportedly causes many human health problems in the lungs, liver, kidneys, skin, eyes and can cause extreme effects on lymphatic systems. These issues, impact ecology too from the factories toxic wastewater that is created during the process of chroming which is usually left untreated.
The alternatives we are driven to look for then, which avoid or at least reduce some of these impacts, are using bio-based materials and are more circular in the design of them as materials. The use of plants and plant waste processes are a solution to delve into.
Beyond toxicity though, we can rely on whole life carbon data steadily being provided through the production of EPDs.
In this table we look at some initial data made available by some manufacturers:
| PRODUCT | Kg OF CO2e FOR 1m2 OF EACH PRODUCT | LINK TO EPD DOCUMENT |
| Dani leathers | 40.32 kgCO2e | Dani EPD 1 |
| Dani Fit Zero leather product | 55.07 kgCO2e | Dani Zero Fit EPD |
| Erly ‘recycled leather’* yearn | 4.25E+00 kg CO2e | Erly EPD |
*(the leather in this product is pre-consumer so not truly recycled material, but the PET content is post consumer)
These EPDs are also providing clarity on the various process and preservative chemicals we mentioned previously, so they are answering more needs we have on transparency and impacts.
Based on this data, if we were to upholster an armchair with traditional leather, we are emitting around 100-150kgCO2e per seat for just the upholstery fabric. If we have say 100 of these in a commercial workplace or hotel/restaurant this would be 10,000-15,000 kgCO2e for this upholstery. The lifecycle in such a case might be 10 years but not usual to extent to 15 years for commercial workplaces for example. So if similar projects did this every 10-15 years, over 60 years we would emit a proportionately large amount of emissions from this one small choice in the design of an interior.
We currently have low circularity, low re-use of this material and such products, but this is where some real sustainable solutions can be found for interiors, and such durable materials as leather. We need to increase circularity of both the upholstery and the products themselves. The durability performance of the material really comes into its own and can justify the carbon weight over time.
Alternative leathers
The above analysis of impacts, in the context of science-based targets for each project, drives us to look at plants… plant-based leather and vegetable natural tanning processes. There are many examples of innovative fabric designs entering the markets looking to replace the traditional problematic ‘leather’. One of the first plant-based leathers invented was made from a non-prickly cactus for example.
This is not to say that there are no impacts or challenges with bio-based leathers. What we are hoping to introduce though is alternative options when the lifecycles of projects and products can’t justify the impact and problems associated with traditional leathers which currently are not overall sustainable.
‘Vegan’ is the leading label of leather alternatives we have today along with ‘faux leather’ and ‘synthetic leather’. Vegan leather is split into 3 simple categories:
- ‘Fruit-based leather’
- ‘Plant-based leather’
- ‘Recycled leather’
Learning about how each of these different leathers are made to resemble the touch, look, and feel of animal leather, is an incredible knowledge boost in terms of sustainability and understanding ways to enhance our perspective.
Some of the materials available today are known as Mycelium (mushroom) leather, Apple skin leather, Pineapple leather (Pinatex), Mango leather, Pumpkin leather, Banana leather, Cactus, and many more; many even are made from the use of recycled agricultural waste such as cork, a true win-win! These composites, or natural synthetics, can be used for all types of spaces and purposes.
Most vegan leathers have undertaken +/- 50k rub tests and further technical performance tests, which differs depending on the composition of each individual material and passed them. Looking at the rub test alone, this is a clear indication that a lot of vegan leathers would comply with use in both commercial and residential interiors, and deal with the durability requirement.
The haptic experience and visual look of vegan leathers is slightly different though. This does form a challenge when one is trying to create the same effect and overall we would avoid going down this way of thinking as it lacks authenticity and those that matter most in occupancy will be able to tell. Occupant education and acceptance is part of the journey though…
As a team that values overall sustainable outcomes, we are looking to support the continuous innovations around vegan leathers, which we expect to release overall less embodied carbon and include higher circularity benefits than traditional options. However, each project is unique, and our deeper understanding of sustainability will ensure we present harmonised design proposals.
[1] The Drawdown report and solutions 2022, https://www.drawdown.org/solutions/plant-rich-diets
[2] https://www.peta.org.uk/issues/animals-not-wear/leather/
