The Environmental Impact of Plastic Bags

By Morgen Henderson

If the modern plastic bag were a Hollywood actor, it would be a PR nightmare for any agent. On one hand, it’s a practical and helpful tool for carrying groceries, holding garbage, or covering our heads in the rain. On the other hand, plastic bags pose dangers to small children, pollute our oceans, and contribute to greenhouse gas emissions. What a mixed bag of pros and cons! But when it comes to our environment, the reputation of plastic bags may be unsalvageable — their pollution is just too dangerous for the planet.

One factor that contributes heavily to plastic bag pollution is overpopulation. The world population in 1950 was 2.5 billion people. It’s now 7.6 billion. And current estimates show population expansion will balloon to 9.8 billion by 2050. And populations of that size use an enormous amount of plastic bags. Check out these EPA stats:

• Every year, one trillion plastic bags are produced around the world
• U.S. consumers use 380 billion plastic bags and wraps every year
• It takes 12 million barrels of oil to produce the U.S. plastic bag demand
• Less than 5% of plastics are recycled in the U.S.

Plastic bags are devastating the planet, from their accumulation in our landfills to the chemical toxins they leach into our oceans. Here are some ways the plastic bags has transformed from a keen idea for conveyance to a serious environmental threat.

The Long Life of Plastic Bags

Let’s start with the “good” news first. Plastic bags threaten our environment because of their long life spans. They’re the Black Knight of pollution because they never die. But their impacts aren’t merely “flesh wounds” to the earth; they’re serious problems for our American highways and byways, tourist destinations, and wildlife. Consider these two sobering statistics: We use plastic bags for an average of 12 minutes, but they take 20 years to decompose. And even decomposed plastic bags aren’t magically gone from the earth. Instead, they break down into microplastics, which contaminate our water and poison marine life. So, the plastic bag represents the ultimate short term gain for a long term loss.

We only recycle a small fraction of polyethylene bags. So, they pack our landfills, taking up more space. And those bags that don’t make it to the garbage or recycle bin pollute our streets, rivers, beaches and forests. Plastic pollution at beaches and parks affects tourism and raises costs of trash collection and maintenance. While this may seem like a “first world” aesthetic problem, the environmental implications are serious.

Plastic bags are also a sanitation problem. Local wildlife often consume plastics or become entangled in them. Plastic garbage flows into drainage and sewer systems, which causes backups. Or the drainage carries them out to rivers, lakes, and oceans. Plastic bags also collect standing water, becoming a breeding ground for disease-carrying insects like mosquitoes.

The Great Pacific Garbage Patch

The vast amount of plastic bags and other items eventually find their way into our oceans. In fact, around 80% of plastics polluting the oceans started on the land. And the tons of floating garbage is growing. So much so, that we now have a giant debris field twice the size of Texas floating within our North Pacific Ocean. It’s called the Great Pacific Garbage Patch (GPGP). This floating island of waste is also known as the Pacific trash vortex. That’s because it’s formed by a convergence of circular ocean currents that corral the debris into a large mass. 

When people hear the phrase “garbage patch”, they think about a floating island composed of soda bottles, plastic bags, and diapers. But floating plastics are only the tip of the plastic iceberg. The GPGP is mostly made of microplastics — pieces invisible to the naked eye. So, think of the vortex more as a giant, cloudy mass of plastic soup. Only the soup never disperses or dissolves. It only gets bigger. And since some plastic sinks to the bottom of the ocean, the Garbage Patch represents only a fraction of the collection. Oceanographers have yet to uncover what lurks beneath the dark waters below the vortex.

The GPGP is a major threat to marine life because of its physical presence and toxic nature. Sea Turtles often mistake plastic bags for jellyfish and eat them. The bags then cause intestinal blockage and death. Trash collected on the surface of the water blocks sunlight from getting to plankton and algae that live below the surface. These small photosynthetic organisms are key parts of the ocean food web. Negative effects to these microorganisms ripple throughout the entire system, threatening larger marine life like dolphins, seals, and whales. And as plastic bags break down, they leach colorants and chemicals, causing health problems for marine life. 

Greenhouse Gas Emissions

Plastic bags come from oil. They’re petroleum products just like our toothbrushes and smartphones. The difference is we use those items much longer. We use plastic bags once and then throw them away, which can really add up if we go shopping on a weekly basis. Compare that to shoppers in Denmark who use four bags per year! All that plastic takes millions of gallons of fossil fuels and oil to produce. Plastic bag production requires burning and using fossil fuels. This one-two punch makes it a major contributor to greenhouse gases like CO₂. But it gets worse.

One recent study shows plastics also release other greenhouse gases (methane and ethylene) as they decompose. The chemical ethylene is one of the most widely used organic substances in the world. Much of it goes into making polyethylene, the chemical in plastic shopping bags. And polyethylene is the most used and discarded synthetic plastic in the world. Worse still, it’s the worst emitter of methane and ethylene compared to any other substance.

Plastic Bag Alternatives

Even though plastic bags pose a major hazard to the environment, there is hope. Many cities around the world have banned single-use plastic shopping bags. So, reducing their use will cut production and help curb environmental effects. Prohibitions on plastic bags also push consumers to adopt alternatives like multi-use, biodegradable cotton bags or bags made from recyclable paper.   

But there are also new technologies and plastic alternatives on the horizon. Polypropylene “green bags” are still made from by-products of oil refining, but you can use them much longer. 

Innovations in plant-based polymers promise the end of plastic pollution. These plant-based plastic bags are made from cassava roots. So, they’re edible and biodegradable even while looking and feeling like plastic. Land and marine animals who eat the bags are able to digest them. So, they’re much less of a threat to sea life. They also breakdown quickly, lowering the chances of making their way from land to the oceans, lakes, and streams. 

Innovations like these help the plastic bag reclaim its once stellar reputation as a handy way to carry in the groceries. By adopting new technologies, we can reform the plastic bag into a functional and eco-friendly tool for humanity again.