Choosing Materials Beyond CO₂
A practical look at material selection in product development
Carbon footprint is an important piece of information. Companies need something measurable to build plans, set targets and track progress, and CO₂ data often provides that basis. When it comes to product emissions, material choices can have a large influence, especially when materials make up a significant share of the overall footprint.
For the same part of a product, one material has a carbon footprint of 6 kg CO₂e/kg and another 3.5 kg CO₂e/kg. Which one would you choose? If reducing emissions is the goal, the answer seems obvious. The second material has the lower footprint, so we should choose that one. But is it really that simple?
In this article, I want to explore what else should be considered before making that decision, and which parameters matter alongside the carbon footprint.
Let’s add a small detail onto our example: Imagine that we need 500 grams of Material A for the part, but 900 grams of Material B to achieve the same strength and function. Now the picture changes:
Material A:
6 kg CO₂e/kg × 0.5 kg = 3 kg CO₂e per part
Material B:
3.5 kg CO₂e/kg × 0.9 kg = 3.15 kg CO₂e per part
Suddenly, Material B, despite having the lower carbon footprint per kilogram, results in slightly higher material-related emissions for the finished part. This is why comparing materials only based on their emissions per kilogram can be misleading. What matters is how the material performs within the product, how much of it is needed, and whether it can deliver the same function.
Depending on the product, a material may need to meet very different requirements. It might need to be strong, lightweight, flexible, resistant to heat or water, or able to withstand years of use. For example, switching to the lower-carbon material might reduce the footprint of a product, but also makes that product wear out much faster. If customers need to replace it more often, some of that environmental benefit could disappear. This is where durability becomes part of the sustainability discussion.
As an example, Apple reports that around 71% of the aluminum used in products shipped in 2024 came from recycled sources. What makes this especially interesting is that increasing recycled content was not simply a sourcing decision: Apple also had to invest in the development of an alloy made with 100% recycled aluminum that could still meet its strict design and performance requirements.
However, even if a lower-carbon material meets all the required performance and durability criteria, there are still other aspects to consider. One of the most important is availability. Finding a promising material is one thing. Producing thousands or millions of products with it is another. If there is currently only one supplier producing it, production capacity is small and the material probably costs several times more than the conventional option.
Is it still a good material innovation? I would say yes. It might simply not be ready to replace the existing material everywhere yet, but it makes sense to start with a small product range, and learning from the first applications. Maybe the supplier needs time to expand production, and further development will bring the price down.
It is important to start with the first applications because a new material’s manufacturing behaviour may be different. It could require different temperatures, machinery, adhesives, or processing conditions. Production yields might change, or additional testing might be required. Sometimes these challenges can be solved quite easily, however sometimes changing one material means changing several other parts of the production process as well. A promising carbon result is only one part of the story. Companies also need to understand what it would take to integrate the material into production.
And of course, another aspect is cost. Smart sustainability decisions need to make sense from a business perspective, so cost cannot be ignored. A lower-carbon material may come with a higher price, especially when the technology is still new. A material that reduces emissions substantially but increases product costs by 2% creates a very different decision from one that increases them by 200%. For a small pilot, that additional cost might be manageable. But once the same material needs to be used across thousands of products, even a relatively small price difference can become significant.
Lastly, we should also look beyond carbon and consider other environmental impacts. A material can perform better from a climate perspective and still create higher impacts somewhere else, for example through water use, chemicals, recyclability, or end-of-life.
A well-known life cycle assessment of milk packaging is a good example. The study compared virgin PET, recycled PET, returnable glass and single-use glass. Recycled PET had the lowest global warming impact, while single-use glass had the highest, mainly because glass production is energy intensive and glass bottles are much heavier to transport. But when marine litter was considered, of course returnable glass performed much better.
This is a good reminder that there is rarely one material that is simply “better” in every environmental category. Ideally, a material change should reduce emissions without shifting the burden somewhere else. In reality, trade-offs happen, and understanding them is part of making a well-informed material decision.
So before making the final choice, it is worth asking:
What is the carbon footprint of the alternative material?
How much material is needed to provide the same function?
Does it meet the required performance and durability?
Can it work with the existing manufacturing process?
Is it available at the scale we need?
What does the change cost?
What are the other environmental impacts?
Overall, the low-carbon material can be a strong starting point, however good material choices happen when carbon data is considered together with performance, durability, scalability, cost and the wider environmental picture.
Sources / Further reading
Stefanini, R., Borghesi, G., Ronzano, A., & Vignali, G. (2021). Plastic or glass: A new environmental assessment with a marine litter indicator for the comparison of pasteurized milk bottles. The International Journal of Life Cycle Assessment, 26, 767–784. https://link.springer.com/article/10.1007/s11367-020-01804-xBajwa, A. U. R., Siriwardana, C., Shahzad, W., & Naeem, M. A. (2025). Material selection in the construction industry: A systematic literature review on multi-criteria decision making. Environment Systems and Decisions, 45, Article 8. https://link.springer.com/article/10.1007/s10669-025-10001-w
Apple. (2025). Environmental progress report 2025.https://www.apple.com/environment/pdf/Apple_Environmental_Progress_Report_2025.pdf
Carbon Minds GmbH. (2026). Comparative life cycle assessment (LCA) of fossil-based and CCU-based EVA copolymer. https://assets.ctfassets.net/hnk2vsx53n6l/6fYmuuG2pveTDbEKhK6k3n/837daaa4c3a4e87bf0bc09bf50f91e4f/Comperative_LCA_for_ON_Running_CM_final_delivery.pdf
On. (2025). Impact progress report 2025. https://s21.q4cdn.com/241001792/files/doc_downloads/impact-report/On_Impact-Progress-Report-2025-6afb2f.pdf
