Glass vs. Plastic: Which Is More Sustainable?

These days, we’re all looking for products with packaging that’s sustainable. And that's a good thing because the average American produces over 1,646 pounds of waste each year (EPA, 2019). So, what is the most eco-friendly packaging material? And specifically, is it better for the environment to buy products packaged in glass or plastic?

Back to Basics: The Difference Between Plastic and Glass

Most durable containers are made from either plastic or glass. So, what’s the difference? It starts with raw materials.

Where Does Plastic Come From?

Most plastics come from petrochemicals, i.e., oil. After drilling and pumping oil from deposits in the earth, it’s separated into different chemicals. Some of these chemicals are used for gasoline or various other purposes, and some are used for making plastic. After more chemicals are added to give the final product the desired properties, the plastic is heated and molded into a bottle or other object.

Where Does Glass Come From?

Just as there are different kinds of plastic, not all glass is the same, but most glass is made from silica, which we get from sand. The sand is mixed with other ingredients and heated in a furnace. Once everything in the mix is melted together, the molten glass is formed into its final shape.

What Happens After Packaging Has Served Its Purpose?

When it comes to sustainability, a key factor is what happens with the materials we use when we no longer need them. Of course, there’s always the option of throwing a used bottle in the trash, but as an eco-conscious consumer, you probably recycle when you can.

Plastic Recycling

We all know that when you’re done with a plastic container, you should put in the recycling bin. But is that plastic actually recycled? Well, yes and no. The process of plastic being reused is sometimes called "downcycling" instead of "recycling." When plastic is reused, its quality takes a hit, and it can't be used in the same way (Geyer, Jambeck, & Law, 2017). The plastic bottle you put in the recycling bin isn’t going to become a new plastic bottle. Recycling plastic is delaying the inevitable — it will eventually end up in a landfill or an incinerator.

Glass Recycling

Glass packaging is considered truly recyclable because it can be reused again and again with no loss in quality. The glass bottle you recycle could be used to make more glass bottles. Besides saving raw materials, it means there will be one less container in a landfill, thanks to you.

You're probably hearing a lot about "closed-loop" recycling these days. Closed-loop recycling uses the same materials over and over to make the same type of product as the original. For example, using a glass bottle, recycling it to make more glass bottles, recycling those, and so on. This strategy is vital to reducing the waste we contribute to the environment and reducing the amount of material we harvest from the environment to make new products. Glass is a prime example of a material that can be recycled in a closed-loop.

The Effects of Plastic Packaging

The percentage of the waste we produce that’s made up of plastic has been increasing since it was introduced decades ago. The majority of plastic produced is used to make plastic packaging — often used only once and thrown out (Jambeck et al., 2015).

Plastic Waste Generation by Industry

Unfortunately, a lot of plastic waste ends up in our oceans. In fact, a 2013 study found that there were more than 268,940 tons of plastic polluting our oceans (Eriksen et al., 2014). This plastic waste doesn’t naturally break down. Since it’s difficult to remove plastic from the sea, the best way to combat this pollution is to reduce the amount of plastic going into the ocean. Sadly, the amount of plastic waste we produce is showing no sign of decreasing.

Plastic Produced Globally

Can We Incinerate Plastic Waste?

Since a significant part of the problem with plastic packaging waste is that it piles up in our oceans and elsewhere, can we simply destroy it? Can we burn plastic to get rid of it? What impact does incinerating plastic have on the environment?

Plastic incineration is more common than you might think. More plastic waste is incinerated than recycled (Geyer et al., 2017). Burning plastic produces tremendously hazardous chemicals. The substances released during incineration depend on the type of plastic burned. PVC, for example, produces several compounds, including colorless phosgene gas (which has been used as a chemical weapon), formaldehyde, and a laundry list of other harmful chemicals. Many of the chemicals released are carcinogenic, meaning they are known to increase cancer risk (Kuti & Nagy, 2016).

How Can We Get Rid of Plastic Waste?

If incinerating plastic isn't the answer, how do we deal with plastic waste from product packaging and other uses? Unfortunately, what makes plastic useful is also its downfall—plastic is sturdy and doesn't degrade quickly. Since plastic "recycling" only pushes the can down the road, the best option for reducing plastic waste and its harmful effects is not to use plastic unnecessarily. There are superior alternatives to plastic in many cases. For example, plastic containers can often be replaced with glass containers. Glass can be endlessly reused and recycled.

Moving From Plastic to Glass

Most plastic waste comes from packaging, packaging used for products you buy every day. The companies making these products don’t use plastic packaging because they want to hurt the planet and the people living on it, they use it because plastic costs them less than glass or other sustainable packaging.

The best way to cause a widespread change in the packaging manufacturers use is to buy sustainably packaged products. By showing businesses that consumers care enough to choose brands that use eco-friendly materials over those that don't, you can inspire change. Reducing plastic waste starts with decisions made by consumers like you. Each dollar you spend on eco-friendly packaged products is a vote for a healthier planet.