It seems obvious: natural materials are necessarily healthy and good for the environment. But that’s not always the case. Energy-intensive processing, chemical additives, unproven recyclability... Is every natural product really more sustainable? We catch up on the latest thinking.
“Beware of received wisdom. Not everything that originates in nature is always more eco-friendly”
The collective unconscious assumes that everything sourced from nature is necessarily good for our health and our planet. Really? It's just not that simple. Simply citing lead or asbestos, both of which are natural in origin after all, is enough to temper the zeal and unravel certain beliefs. The word ‘natural’ tells us only about the origin of a material: vegetable, mineral or animal. It certainly doesn’t mean that a product is absolutely healthy and has zero environmental impact. For example, some bio-based materials may be mixed with other raw materials during the processes that turn them into finished products, which are then treated with chemical additives to enhance their properties. These additives - which may be fungicides, insecticides, hydrophobic flame retardants, etc. - are not necessarily neutral in terms of their environmental and health impacts. It’s also important to bear in mind that although bio-based materials are certainly renewable, they are not always responsibly managed.
Beware gray energy
Regardless of its origin, the environmental impacts of a product must be assessed throughout its entire life cycle, from raw material extraction through production to end-of-life processing. And in this little game, the winners aren’t always so-called ‘natural’ products. Some crops, like cotton, consume very large amounts of water when grown intensively. Processing the crop then requires energy and involves components that also used energy in their production. Other bio-based materials are produced and processed so far from where we live that their transportation also uses gray (or hidden) energy to move them around the planet before arriving at their destination. Lastly, when some products reach the end of their life, there’s no other option than to bury them in landfill or incinerate them. Conducting life cycle analyses in accordance with international standards is the only way to calculate and compare the impacts of different products that fulfill the same function, especially in terms of the energy they will have consumed or the amount of carbon that will have been emitted over their full life cycle.
Local and sustainable
The sustainability of a product must therefore be assessed over its full life cycle, and we must also look beyond environmental and health impacts to measure its lasting benefits for users. This is why the ‘natural versus industrial products’ face off is irrelevant... An insulation material like glass wool seems to square the circle. And rightly so, since it is made from cullet (crushed glass from broken windshields, bottles, etc.), an infinitely recyclable material!
With more than two decades of commitment to sustainable development, Saint-Gobain subsidiary company ISOVER recovers and recycles used glass wool though its ISOVER Recycling service, which collects this material from worksites and recycles it for use in manufacturing new insulation products. It’s the first service of its kind in the world. In manufacturing its new glass wool, ISOVER uses a bio-based binder that guarantees very low emissions of volatile organic compounds (the VOCs we hear so much about). Lastly, compressing the product by a factor of eight considerably reduces the ecological impact of its transportation.
Other insulation materials, such as wood fiber, are also making their own contribution to sustainability. Produced from local resources in the form of forestry by-products, these materials deliver high levels of thermal and acoustic performance, at the same time as saving natural resources and imposing a smaller carbon footprint.
Bioplastics: are they really organic?
In this innovation race, new and allegedly more eco-friendly materials, such as bioplastics, have begun to appear in the market. Perhaps the most high-profile is PLA (polylactic acid), which its mainly agricultural in origin (corn starch, wheat starch, sucrose, etc.) and has ambitions to oust oil-derived polymers. The promise looks seductive on paper, but Associate Professor of Materials Science Elise Contraires nuances the words: “Beware of received wisdom: bioplastic doesn’t mean biodegradable. Everything depends on molecular structure!” she explains. “Some oil-derived plastics are readily biodegradable, while PLA requires special industrial conditions. It's not necessarily eco-friendly, and even less profitable.”
Zero carbon, zero chemistry
Since it lacks a recycling process, PLA is ironically becoming a single-use plastic, while its industrial cousin PET is wisely following the path to recovery and recycling. This then is the moral of the story: not everything natural is necessarily sustainable. Neither is it necessarily good for our planet!
Finally, when we think about sustainability, we must anticipate the future by focusing on the issues around recycling materials at the end of their life. Above all, it means looking at environmental footprints in their totality as we strive to identify the ultimate material - whether natural or synthetic - that comes close to delivering ‘Zero carbon and Zero toxicity’.
Photos credits : Franck Dunouau/Saint-Gobain Glass & Saint-Gobain Isover