Sustainability Showdown: Polyurethane VS Animal Skin
Let's break it down...
When considering ethics, it should be obvious that any material not made from a slaughtered animal ought to win out over one that is. When it comes to the sustainability credentials of materials though, there tends to be more debate.
It’s clear that synthetic leather is not natural. Polyurethane (also known as PU), the most common synthetic alternative to leather, is most often created from a petroleum plasticizer - often considered far from ideal.
So, often people assume that animal leather is better for the environment as it’s considered ‘natural leather’’. Nature is good, so that makes sense, right? It would, if animal leather were actually natural.
If we go back to the very start of the animal leather supply chain, we find, unsurprisingly, animals. Most commonly, bovine animals like cows.
This in itself, is unnatural.
Across the globe we have bred cows into existence for the purpose of their slaughter, in all different environments to which they are introduced. Globally, there are over 1.4 billion cattle, meaning 1.4 billion extra animals requiring land to live on, and 1.4 billion extra mouths to feed. In a world more strained for natural resources than ever before, farming animals is eating up the earth.
Farming cattle is linked to 94% of land clearing in Great Barrier Reef catchments, and 80% of deforestation in the Amazon. Between 2015-16, about 400 million trees were cut down in Queensland, Australia, with the vast majority of clearing being due to animal farming. This intensive destruction results in a loss of biodiversity and habitat loss for native animals, and in turn the potential for extinction. This is a growing concern for many species, including koalas. None of this seems very natural.
Land clearing for mining, connected to the production of synthetic leather materials, is of course a strain on the planet. But while there is no doubt that polyurethane is no perfect solution to leather, consider this: 92% of Australian land clearing is for animal agriculture (56% specifically for cattle), while mining, combined with every other industry makes up only 8%.
Greenhouse Gas Guzzling
When we consider greenhouse gas emissions, polyurethane beats leather. It’s really saying something about the impact animal farming has on the planet when a petroleum-based synthetic material has less than half the global warming impact than animal leather.
Animal leather also uses far more water, and negatively affects far more natural water resources through eutrophication, which can kill animal life in the water due to a lack of oxygen. In fact, leather was found to be the single most impactful material to produce from cradle to gate, by the Global Fashion Agenda in their report with the Boston Consulting Group.
End of Life
But what about the ‘end of life’ impact of these two materials?
Even if it is better for the planet to produce, a synthetic material like polyurethane leather is not going to biodegrade and feed the soil anytime soon. If you’re listening to the industries self-promotion, supposedly ‘natural’ animal leather biodegrades, but this is not the reality.
It’s true that animal skins themselves are natural and biodegradable, just as the entire animal carcass the skin is pulled from is. However, leather tanning, whether it be chemical or vegetable tannin based, is a process that exists specifically to stop the decomposition of animal skin. That’s why there are leather shoes, still perfectly intact, that are 5,500 years old.
What we’re seeing here is that certainly, polyurethane is not the future of eco-fashion. It doesn’t biodegrade, and it does require mining, which means greenhouse gas emissions and land clearing.
But what we are seeing even more clearly, is that the leather is far worse a material choice. Leather also does not effectively biodegrade, it results in over double the global warming impact during production, and destroys far more native land, resulting in a loss of biodiversity and species extinction.
Wrapping it up
Animal skin and polyurethane leathers are the two most common options we have available right now. If we want to reduce our impact on the planet, we need to be choosing the material with a lesser impact.
Before we even consider the truly sustainable leather alternatives like Pinatex, cork, washable paper and recycled synthetics, which are fantastic but less readily available (for now), we can switch from conventional animal to conventional vegan leather.
Reduced impact definitely doesn’t mean perfect, but when it means saving lives while harming the planet less, it’s a clear win.