9. Boot people: is synthetic (nylon) better than leather (a byproduct)?
Kevin: Again, lots of variables even if sustainability is the only dimension considered—not material applicability. Just a little more context rather than try to answer a question that is somewhat unanswerable without specific and comparable LCAs.
Synthetics for boots requires toughness therefore it is commonly nylon—an extremely durable polymer—derived from petroleum. Not only does nylon have a relatively large ‘feedstock’ footprint, but since it so relatively tough—it breaks down very, very slowly when discarded.
Leather, being a ‘natural’ material varies widely in its grade/cut and overall quality. But although it is a by-product of the production of meat—the process for turning it into a useable material can be very harsh. Additionally tanning practices vary greatly depending on the environmental sophistication of the tannery.
The Leather Working Group tannery rating system is a great tool to ensure that best practices are being followed. Clearly you want boots made from leather which have been tanned in facilities of Bronze status or better (http://www.leatherworkinggroup.com/)
Jill: There has been discussion now about referring to leather only as a byproduct from an environmental point of view. A more accepted way to look at it today is by allocated impact. So if you have a cow and x% goes to meat and x% goes to leather, that allocation of impacts would be assigned at the same percentages. This is a more fair comparison because if leather wasn’t available, there would be a different material taking its place, like nylon.
The point of view that I take on this type of a question is to look at the product and determine what is best for the performance and durability first. If someone buys a product with an ‘evironmentally preferred material’ on its green merits but doesn’t like it and use it, it isn’t a good green product.
So if we start with the performance and durability and then make the appropriate raw material the greenest they can be, we are going to produce better products and lessen our impacts. This also helps to show others that will continue using different raw materials that there is a better way to produce almost every raw material.