It’s estimated that 1 MILLION plastic bottles are sold EVERY MINUTE. Earlier this year Coca Cola revealed that it’s sales of glass bottles have increased by 14% in the past year as the result of people boycotting plastic. So which material is more ‘sustainable’?

It’s not as simple as glass vs plastic. When considering what material or product to use you need to think about how it’s made, how it’s transported, how it’s used and how long it lasts, how it’s disposed of and where it ends up. Now that’s a lot to think about. So we thought we’d write it all down for you.

What it’s made from

Glass is made from liquified sand, soda ash (naturally occurring sodium carbonate) and limestone. These materials are pretty common, but limestone must be mined which can cause damage to local environments.

Plastic is made from oil and gas. These are non-renewable resources which will run out.

How it’s made

Glass is made by heating the ingredients to high temperatures (around 1700 degrees), then pouring the molten liquid into moulds to set. To get such high temperatures a lot of energy must be used – we must think about how ‘green’ this energy is. If a glass bottle is made from recycled glass, the temperature needed is a lot lower.

Plastic is made by a process called ‘polymerisation’. The components of crude oil are separated by heating (different parts have different boiling points) and are then joined together to create plastics. Different types of plastic are made by putting together these components in different combinations and adding chemicals to give different properties.

How it’s transported

The carbon footprint to transport bottles depends on a few factors: distance transported, type of transport and energy used to power the vehicle.

Glass is heavier than plastic, so its transport needs more energy. Glass is also more fragile than plastic so cannot be packed as tightly together during transport.

How it’s used

Glass is a more durable material than plastic so lasts longer. Plastic does last a long time (as you know, they can take 450 years to break down!) but chemicals from the plastic bottle can leach into the water inside. Plastic bottles can be re-used and do NOT have to be single-use, but the effects on human health are unknown.

How it’s disposed of

BOTH glass and plastic CAN be recycled. In a direct comparison, the recycling of plastic takes less energy that that of glass. The problem is that not all types of plastic can be recycled, and recycling rates vary a lot from country to country. In the US about 30% of plastic bottles are recycled and in Norway a whopping 97% is recycled. Please share your secrets Norway.

Plastic that is not recycled and goes to landfill, or worse, escapes into the environment, takes 100s of years to break down. As plastic ‘degrades’ it breaks down into tiny pieces called microplastics and can absorb toxic chemicals, killing an estimated 1 million marine animals every year. It’s true that glass also pollutes nature – we’ve all seen ‘sea glass’ on the beach – and can harm wildlife. But glass does not absorb toxic chemicals and does not float like plastic. As a pollutant, glass is ‘lower impact’.

Not as simple as it seems

The water is still a little murky when it comes to deciding whether to use glass or plastic bottles. So what can we do about it?

It comes back to the old 4 R’s: refuse, reduce, reuse, recycle. If you don’t need a bottle, don’t use it. Re-use what you have for as long as possible – get a reusable water bottle if you don’t already have one. Recycle when you can. When it comes to recycling, innovation is needed to improve local recycling infrastructure to process more materials and reduce transportation distances.

We also need to think about whether we need bottles at all. In an ideal world we would not need glass or plastic bottles – we’d all have re-usable drinks containers full of tap water. Unfortunately we don’t live in a perfect world yet – 2.2 billion people do not have access to clean drinking water and bottled pure water is one of the only options.

Switching to re-usable water bottles in areas of safe drinking water is one part of solving the problem. The other part is improving sanitation and increasing access to clean water across the globe.

We’re sorry that the answer isn’t straightforward or easy. What’s important is that we stay informed and know where improvements need to be made.

Information taken from:

• https://earth911.com/living-well-being/recycled-beverage-containers/

• https://www.telegraph.co.uk/news/2019/01/27/glass-bottles-could-worse-environment-plastic-coca-cola-warns/

• https://www.water.org.uk/news-item/national-refill-day/

• https://www.nationalgeographic.com/environment/2019/08/plastic-bottles/

• https://www.explainthatstuff.com/glass.html