How Long Does It Take for Plastic to Decompose?

Plastic is both a blessing and a curse. It has revolutionized the way we live for the better, but it also presents us with a big problem. Namely, what do we do with it and where does it go once we’re finished using it? Every toothbrush, drinking straw, Styrofoam clamshell and pen you’ve ever used is still on this earth — either in its original form, recycled into another product or slowly breaking down into tiny pieces called microplastics.

Plastic is everywhere, and by design, it’s made to last decades, if not hundreds of years. It’s incredibly useful, but it’s bad in terms of the waste created. The truth is we really don’t know how long plastic lasts. Plastic has only been in circulation since 1907, and experts estimate that some plastics can last hundreds of years before they finally break down. And it keeps piling up in the strangest of ways, like the Great Pacific garbage patch just floating in the middle of the ocean. 

How Long Does It Take for Plastic to Decompose? 

Plastics can take anywhere from 20 to 500 years to decompose, depending on the material and structure. Additionally, how fast a plastic breaks down depends on sunlight exposure. Like our skin, plastics absorb ultraviolet (UV) radiation from the sun, which breaks down the molecules. This process is called photodegradation, and it’s why landfills often expose plastic waste to the sun to accelerate the breakdown process. 

For example, single-use plastic grocery bags take about two decades to break down. In contrast, plastic water bottles made with polyethylene terephthalate (PET), a common type of plastic, are estimated to take approximately 450 years to fully break down. 

Here’s are the estimated decomposition timelines for common plastic waste products: 

Why is Plastic So Difficult to Degrade Anyway?

It’s simple — plastic isn’t natural. Although it is derived from petroleum, which is processed from naturally occurring crude oil, plastic does not occur in nature. There’s lots of science behind it, but it mostly involves the chemical bonds of plastic vs. the molecular bonds of organic matter like an apple. Plastic’s carbon bonds aren’t the same as the chemical bonds found in nature, making it harder and more energy-intensive to break them down. 

Moreover, as plastic degrades, it can leak toxins into the soil around it, leading to a whole host of other issues researchers must tackle.

From Plastic-Eating Bacteria to Biodegradables

There are, however, new kinds of plastic on the market: Biodegradable plastics, or bioplastics. While bioplastics aren’t derived from nature, they get their name by their ability to easily biodegrade. It involves those chemical bonds we talked about earlier. 

Some scientists have created plant-based plastics using corn or sugarcane as a base material. Other scientists have tweaked the chemical bonds of petroleum-based plastics so it’s easier for nature to break them down. The other and final category is some combination of the two: plant-based and fossil-fuel-based plastics. 

Another — and very recent — innovation is the discovery of plastic-eating bacteria. Researchers discovered the species at a dumpsite and learned that it uses plastic as food. Moreover, it can survive the toxic chemicals that could be released from the breakdown process. 

How You Can Keep Plastic Waste Out of Landfills and Oceans

If you’re reading this, chances are you want to leave this world better than you found it. We’ve got just the right resources for you. From learning how to recycle plastic (the right way) and reducing your plastic pollution to learning how to compost, reduce your food waste, and shrink your carbon footprint, we have the answers to your eco-friendly living questions.

Get started on your path to greener living with these articles on recycling, sustainability and downright responsible living! 

• Your Gateway Guide to Green Living
• How to Recycle (and Do it Right)
• Tips to Reduce Your Plastic Pollution
• Thing You Might Be Recycling Wrong
• The Four Essential R’s of Sustainability