6.4 Materials: Glass

Author: Amy Nguyen

ABSTRACT: Glass is a material that impacts our everyday routines. From consumer products and packaging to entire city blocks flanked with glistening skyscrapers, glass has become an increasingly popular material of choice. How is this growing use of glass sustainable, and what role does this material play in our carbon emissions?

Image: Glass building by SevenStorm JUHASZIMRUS from Pixabay


Glass is primarily made of three raw materials: silica sand, soda ash, and limestone (Kovacec et al., 2021, p. 188). Because of these natural ingredients when glass deteriorates it remains stable, releasing no harmful chemicals and leaving minimal impact on the environment (Nordmeyer, 2018). However, West (2018) has found that it can take upwards of a million years for glass to break down, and although this material is made of natural ingredients not only are vast quantities of these raw materials needed, but glass production also requires a substantial amount of energy (Kovacec et al., 2021, p. 187). In regard to limiting our carbon emissions, the most sustainable quality of glass occurs in its recyclability.

Glass Packaging. When it comes to containers and packaging, glass materials are 100% recyclable. This means that glass can be recycled again and again without loss in quality (West, 2018). This makes glass particularly appealing in comparison to packaging alternatives like plastic, whose recyclability is complex and subject to vast limitations. Additionally, while a glass container sitting in a landfill can take a million years to disintegrate, a glass bottle can be recycled and reproduced as a new container in just thirty days (West, 2018). The use of glass cullet is significant to this process. Glass cullet is made of rejected and/or waste glass, and it can be used in place of raw materials. Glass cullet cuts down the consumption of energy used in the process of melting raw materials and significantly reduces consequent carbon emissions (Kovacec et al., 2021, p. 190). Nordmeyer (2018) summarizes the importance of glass recycling by everyday consumers:

80 percent of all recovered glass bottles are made into new glass bottles. Why does this matter? Because every 10 percent increase in recycled glass results in a 5 percent decrease in emissions and a 3 percent decrease in energy consumption.

Glass and Architecture. Beyond packaging everyday products, glass is widely used in architecture. Although its aesthetic appeal remains debatable, it cannot be denied that these glass structures play a significant contribution to our greenhouse gas emissions.

According to The Atmospheric Fund, the buildings sector accounts for 60% of Toronto’s greenhouse gas emissions (Lu, 2017, p. 7). This is just below New York whose buildings make up 66% (Gaviola, 2019). Gaviola (2019) identifies that the primary causes responsible for building emissions are electricity and natural gas consumption – in other words our typical sources of heat, refrigeration, and lighting. Due to the nature of the material, glass buildings are extremely sensitive and susceptible to the drifting climates in which they exist. Alter (2018) summarizes: “these buildings rely on a continuous supply of heating or cooling to be livable. When that goes, the occupants might as well pitch a tent on the balcony”.

What Can We Do About It? From a product design and packaging perspective there are several advantages of using glass: glass can be produced from abundant raw materials; it holds high intrinsic strength and transparent qualities; and it is 100% recyclable (not to mention it does minimal harm to the environment upon ultimate disposal) (Kovacec et al., 2021, p. 187). However, with the energy required in the production of new glass materials, further work needs to be done to not only educate the general public on the benefits of glass packaging, but the value of their subsequent recycling. Further, within Canada glass recycling targets should move towards examples set by leading countries such as Sweden, Switzerland, and the Netherlands where glass return rates are higher than 90% (Kovacec et al., 2021, p. 192). For context the target recovery rate of glass in British Columbia was just 75% in 2020, which was achieved in 2018 (Recycle BC 2018 Annual Report).

Similarly (and seemingly in the opposite direction), in terms of architecture it is imperative that more is done to educate the public on both the environmental and personal cost of glass buildings. Marine Sanchez agrees that if this was general knowledge among the public the demand for glass buildings would see a decline, making room for even more comfortable living solutions that simultaneously save the planet (as cited in Gaviola, 2019). The Passive House standard is a feasible and attractive alternative that can make homes and office buildings comfortable examples of energy efficiency. If planned correctly, this is done at little to no extra cost and can reduce the cost of heating by 90% (Gaviola, 2019). So, while more work needs to be done to educate the general public, Sanchez also stresses the need to inform our colleagues whose decisions can shape our new normal:

If you don’t explain to the people in front of you, the contractor, the developer, the architect, the owner, why we’re trying to do this, then it is met with resistance. But it’s hard to change people and we need to make this the new normal. It’s not the technology that is holding us back. (as cited in Gaviola, 2019)


Alter, L. (2018, October 11). Another Reason Not to Build Glass Towers: They Are Not Resilient. Treehugger. Retrieved February 16, 2021, from https://www.treehugger.com/another-reason-not-build-glass-towers-they-are-not-resilient-4850265

Gaviola, A. (2019, September 7). Glass Skyscrapers Have Turned Entire Cities Into Energy Vampires. Vice. Retrieved February 16, 2021, from https://www.vice.com/en/article/ywy9ek/condos-and-office-towers-are-the-biggest-source-of-greenhouse-gas-emissions-in-canada

Kovacec, M., Pilipovic, A., & Stefanic, N. (2021). Impact of Glass Cullet on the Consumption of Energy and Environment in the Production of Glass Packaging Material. Recent Researches in Chemistry, Biology, Environment and Culture, 186-192. Retrieved February 16, 2021, from https://www.researchgate.net/publication/260320028_Impact_of_Glass_Cullet_on_the_Consumption_of_Energy_and_Environment_in_the_Production_of_Glass_Packaging_Material

Lu, J. (2017, December). Greenhouse Gas Emissions Inventory for the Greater Toronto and Hamilton Area(Rep.). Retrieved February 16, 2021, from The Atmospheric Fund website: http://taf.ca/wp-content/uploads/2017/12/TAF_2015_GTHA_Emissions_Inventory_2017-12-06.pdf

Nordmeyer, J. (2018, April 16). How glass is good for the bottom line & the environment. Retrieved February 17, 2021, from https://www.brewbound.com/sponsored/glass-good-bottom-line-environment/

Recycle BC 2018 Annual Report (Rep.). (2018). Retrieved February 17, 2021, from https://recyclebc.ca/wp-content/uploads/2019/06/Recycle-BC-2018-Annual-Report-1.pdf

West, L. (2018, March 13). Benefits of Glass Recycling. Treehugger. Retrieved February 16, 2021, from https://www.treehugger.com/benefits-of-glass-recycling-1204143

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