It’s a hot June afternoon and you’re in a grocery store browsing the refrigerated aisle. Rows of colorful drinks pass through your eyes. Suddenly you find it—coconut water, at last! Just as you pick up the plastic bottle, you notice your favorite brand now comes in cartons, aluminum cans, and glass. You tout yourself as a fairly “eco-savvy” consumer, so you replace the plastic bottle for the glass option. And it’s the wrong choice.
How do we know this is the wrong choice? Every packaging material has a host of different impacts—from its extraction to its production to its disposal—making comparisons complicated, to say the least. Lucky for us, people dedicate their careers to making comparisons like these, often using the tried-and-true life cycle assessment (LCA). LCAs will take a product, such as a plastic bottle, and compare its impacts on climate change, resource usage, ecosystems, and human health over the course of the product’s life. Last year, an extensive review1 of 53 peer-reviewed studies aimed to understand the state of the art in LCA for packaging alternatives compared to plastic. So how do materials like plastic, paper, metal, and glass compare?
Glass
We’ll start with the clearest result. Despite being widely considered a sustainable option due to its recyclability and natural composition, glass ranks the worst on nearly all impact categories. Since glass has an extremely high melting point compared to aluminum and plastic, producing the same amount of material entails much higher emissions from energy use.2 In addition to requiring more raw material, glass is also substantially heavier than other materials, requiring higher emissions to ship it.
“But wait,” you might say, “at least glass can be recycled easily.” The issue is that recycling glass requires additional energy for the melting process, creating more emissions. While recycling is still better than landfilling because it saves on virgin material, it is far from an eco-friendly option.
“Well,” you might protest, “I reuse my glass containers!” Again, the story is mixed. One study found that in order to have the same overall impact as plastic, glass products can require at least 50 reuses.3 Even with this number of reuses, sanitizing the glass can make it perform worse than a single-use product4 due to the impact of the heated water it requires.
Plastic, Paper, and Aluminum
Here is where things get complicated, so bear with me. According to the review, plastics often perform better than other packaging materials. Why? It comes back to the material’s weight and the quantity required per package. Plastic is highly lightweight, saving emissions from transportation, and less overall material is used per product. Unlike glass, it has a relatively low melting point, meaning further environmental savings when recycled properly (even accounting for transport emissions from recycling). Even if packaging is only used once and discarded, plastic can outperform other materials since it requires fewer resources to produce and less material per package.
But plastics have a major issue that studies to date have been unable to fully account for—plastic leakage can substantially disrupt ecosystems, and the material virtually never biodegrades. In contrast, paper packing can biodegrade easily, but its fibers can only be recycled around six times.5 Since paper production entails substantially more resource usage and pollution from emissions, paper packaging is not necessarily more sustainable than plastic.
Aluminum might be the most balanced option: It has similar advantages to plastic in weight and material usage. Even though it doesn’t biodegrade, aluminum is endlessly recyclable and doesn’t leach into the environment if littered. Aluminum products generally are produced with a high proportion of recycled material as well, which greatly reduces the extraction and use of virgin material.
Takeaways
As it turns out, heuristics like “bio is better,” “plastic is worse,” and “recyclability takes priority” oversimplify things when it comes to the sustainability of packaging options. Here are my takeaways from all of this:
- Glass is generally the worst packaging option, but this could change if local reuse initiatives offered a way to efficiently sanitize and redistribute containers.
- Paper and plastic packaging have opposing strengths and weaknesses. Choosing plastic entails huge savings on resource usage and greenhouse gas emissions, while choosing paper avoids dangerous microplastic contamination and litter. In the future, bioplastics may advance to prevent this sort of pollution, but at the present time they are highly resource intensive and difficult to recycle or compost.
- The picture is variable for other materials like wood and textiles.
- Aluminum seems like the best choice relatively, provided it is recycled properly.
Aside from choosing more sustainably packaged products at the store, you can consider reusing packaging whenever possible. I find there’s often no need to buy plastic wrap or bags when you have bread bags or packaging from items. At restaurants, you can also opt to dine in instead of take out. If you need to discard an item, recycling is still the best disposal method, though imperfect.
- Dolci et al. (2024), Waste Management & Research
- De Feo et al. (2022), Journal of Cleaner Production
- Boutros et al. (2021), Journal of Cleaner Production
- Fetner and Miller (2021), The International Journal of Life Cycle Assessment
- Paper Making and Recycling, EPA Archives
Read more by Drew Schoenfeld at substack.com/@drewschoenfeld.