Which Is More Sustainable: Glass or Plastic?

Many people wonder whether glass is the best alternative to plastic in terms of sustainability, but the answer is more complicated than you might hope.

Both glass and plastic affect the environment negatively, as with most man-made materials. So, leading a sustainable life might make you think you need to cut glass out as much as plastic.

Yet, glass is more sustainable in the long-term compared to plastic because it can be reused and recycled many times over without contaminating food or exposing us to as many health hazards.

Producing glass consumes a lot of energy though, so buying recycled glass products is the best option when looking for your next vase, bottle, or jar.

Is glass more environmentally friendly than plastic?

The debate between glass and plastic has been ongoing for some years.

The environmental impact of plastic is mostly in its degradation, as plastic breaks up into microplastics that harm the environment.

Glass also isn’t biodegradable but it doesn’t form harmful particles, and instead can be reused and recycled without producing microplastics.

Glass takes thousands of years to degrade when not recycled, shown by glass found buried from ancient civilizations.

According to a study from Southampton University, beverages packaged in glass bottles are less environmentally friendly than those packaged in PET bottles or aluminum cans.

This is largely due to the glass melting process, which releases “a high level of gasses particularly carbon dioxide (and its equivalents)”.

The study determined that plastics are less impactful when designed for a single-use basis because they are lighter and require less manufacturing energy, but the reuse of glass bottles was not considered.

In the UK, glass bottles used for milk deliveries would be reused 20 to 40 times. If we reuse glass bottles more often and as much as possible before recycling them, we could cut the impact of glass even further.

Glass has the most impact on marine aquatic ecotoxicity, which affects ecosystems underwater.

The production of automobile laminated glass in China was found to affect marine aquatic ecotoxicity by 92.2%, compared to a 1.75% global warming potential.

It’s not clear how glass impacts marine ecosystems, though fish and other aquatic organisms could be cut on fresh glass entering the environment.

However, plastics contain many additives, some of which are biodegradable and not harmful, but others leach into the environment and cause harm.

Phthalates and bisphenol A are the most well-known harmful substances found in common plastics.

Phthalates are used as plasticizers in many kinds of plastics, especially polyvinyl chloride (PVC), the third most-produced type of plastic.

Phthalate-containing PVC is used for plumbing, cable insulation, flooring, signs, inflatables, detergents, nail polish, hair spray, and shoes.

Restricted and regulated in some countries, phthalates are thought to have “negative long-term impacts on the success of pregnancy, child growth and development, and reproductive systems in both young children and adolescents”, according to a 2021 study.

In aquatic animals, phthalates cause oxidative stress, metabolic disorders, endocrine disorders, and immunosuppression. Together with microplastic contamination, phthalates can be linked to bleached coral reefs.

This is why companies like Sun Bum specify that their biodegradable sunscreens don’t contain phthalates and other environmentally harmful substances. Phthalates are used in sunscreens to add fragrance.

Even worse, of the 129 priority pollutants listed by the Environmental Protection Agency, 78% of chemical pollutants regulated by the EPA are found in plastics.

These chemicals can cause a variety of health problems in humans and animals, depending on levels of exposure and other factors.

Glass doesn’t have anywhere near as many health concerns for consumers, though health and safety are extremely important to lower exposure to lead during glass production.

Is glass better than recycled plastic?

Overall, recycled plastic measures up better against glass, but it still isn’t good for the environment.

The study into beverage packaging found that recycled plastic has less of an impact on the environment than glass or recycled glass. However, that doesn’t take into account multiple uses, which glass is better for.

Only 9% of plastic is recycled, with 12% incinerated and the remaining 79% sent to landfills.

By 2015, over 8.3 billion metric tons of plastics had been manufactured. In comparison, the average glass recycling rate in the EU in 2019 was 74%, with over 12 million tons of glass bottles and jars recycled across Europe.

It’s hard to compare the two figures, but the recycling rate is important to remember, especially as recycling processes improve and plastic is swapped for glass. If we don’t reuse glass packaging, we could still be adding tons to landfills every day.

Recycled plastic is just as, if not more, harmful to your health as single-use plastics.

If your choice is between plastic or recycled plastic, you should always opt for recycled plastic, unless it’s to do with food or drinks.

The same goes for anything single-use – as long as you recycle it properly afterward.

But if you want something that lasts and can be consistently recycled, glass is better than recycled plastic in the long term.

Why is glass better for the environment than plastic?

While it’s a thin line between the two, given the amount of energy required to produce glass, glass is better for the environment because it doesn’t contain as many pollutants or contaminating particles as plastic.

Glass is far from perfect, but the harm of microplastics in the long term could outstrip the impact of glass entirely.

We still don’t quite know how damaging microplastics are for the environment, while glass has been around for thousands of years.

It’s thought that there were “between 15 trillion and 51 trillion microplastic particles floating in surface waters worldwide” in 2015.

The only way to reduce microplastics is to stop buying plastics, and if the choice is between glass or plastic?

Your choice should always be glass! Even if it’s for your own health, glass is less harmful, especially if you buy recycled glass already.

Some studies on the environmental impact of glass vs plastic take into account the high energy demand needed for glass without considering the harm of microplastics.

We should also consider that petroleum is a finite resource, one that can’t be easily recycled again and again, which is why the swap to natural polymer plastics like corn starch plastics are one of the best plastic alternatives.

That doesn’t mean that PLA bioplastics are perfect either!

Glass production and recycling need to improve, but from a consumer’s end we need to make sure to purchase recycled glass products and make the absolute most of them.

Glass is a healthier choice for us all, but the convenience of plastic makes them preferable to many companies looking to create affordable products or packaging.

It’s better to focus on cutting down our single-use products and opt for more sustainable alternatives, but if the choice is strictly between glass and plastic, glass is better overall.

You should always opt for recycled glass products that you can reuse time and time again.

Does glass actually get recycled?

Glass is one of the most recyclable materials you can get. As long as you put the whole glass in the recycling, it should be recycled with no trouble at all.

Most councils and recycling schemes advise against adding shattered glass to the recycling – this isn’t because it isn’t recyclable! It’s to protect workers from being cut by shards.

Always be careful when placing glass into recycling bins or collection points to ensure it doesn’t shatter.

Glass can be recycled over and over again without any loss in quality.

By buying recycled glass, you can rest assured that your glass can be recycled again when you’re done with it, to help other people cut down on waste.

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