• Valinda

Glass vs Plastic

Updated: Apr 17

When you first enter the world of zero wasting, you will see glass everywhere. From mason jars to water bottles all made from glass. It is a pretty popular product. However, compared to plastic, is glass really the most environmentally friendly option? Let’s find out.



Glass

Resources: The production of glass requires sand. More specifically soda-lime-silica. This specific type of sand can be found in riverbeds and seabeds (so no desert sand). There is not an endless supply of this sand in the world. Actually, we are running out of it. We, humans, consume if much faster than our dear planet earth can replenish it.

Manufacturing: To create glass, sand needs to be heated so it can be formed. Then it is washed and sterilized so it can be sold (this is the very short version). This process requires energy which results in the emission of greenhouse gasses. For not recycled glass this is 8.4 kg CO2 per kilogram of glass produced while for recycled glass this is: 1.4 kg CO2 per kilogram of glass. For comparison: 1 kg of CO2 is equal to the emission of driving an average car for 2.3 miles or 3.7km.

Recycling: Glass can be recycled endlessly without loss of quality but only about 33% of all glass in the US is recycled (in the Netherlands this is 90% due to its super-efficient collection system). The remaining 67% ends up in landfills.

Other problems:

- Glass is very fragile. It breaks more often during transport and it is much heavier compared to plastic. Resulting in an increase in emission gasses.

- Glass hardly decomposes in nature (over 1 million years).

- Pollutants that are released during the manufacture of glass are sulfur oxides (SOx), nitrogen oxides (NOx).


Plastic

Resources: Most plastic (excluding bio-based plastic) is petroleum-based. Obviously, this is a non-renewable resource that we will run out of in a few years. Drilling for oil causes many problems like destroying ecosystems and marine life.

Manufacturing: Crude oil needs to be cracked (breaking large polymers in short polymers) so different kinds of plastic can be produced (this is the very short version of how plastic is made). This process requires energy for heating which results in the emission of greenhouse gasses. For not recycled plastic this is about 1.8 kg CO2 per kilogram of plastic produced (this differs a bit per type of plastic but it is a good average) while for recycled plastic this is: 1.5 kg CO2 per kilogram of plastic. Remember: 1 kg of CO2 is equal to the emission of driving an average car for 2.3 miles or 3.7km.

Recycling: Unfortunately, only 9% of the plastic in the US is recycled. Not all plastic can be recycled and plastic can’t be recycled endlessly (yet). Every time plastic is recycled, the polymers they are made from get shorter and shorten reducing the quality of plastic. Plastic can be recycled 2-3 times before the quality downgrades to a point where it can no longer be used.

Other problems:

- Plastic takes 500 years to decompose (1000 years in a landfill) releasing microplastics into the environment while doing so.

- Only clean plastic can be recycled.

The CO2 emission in the comparison is for the production of plastic and glass only. So, this will be even higher for glass when transportation is included as it is so heavy. Also, the greenhouse emission for sending your consumable plastic to a landfill is not included.

So, both have their pros and cons. Glass has a much higher greenhouse gas emission but can be recycled endlessly. Plastic has a lower greenhouse gas emission but consumes lots of non-renewable resources.

Try avoiding buying new plastic and opt for recycled when possible. However, if you have the option you should try to reuse the glass bottles you already have.


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