Plastic breaks up, not down

But how do we know that? And what is the difference?

5 min read

I hear you – if plastic has only been around a few decades, how do we know it will take hundreds (or even thousands) of years to break down?

Scientists use respiration testing and UV-degradation testing to predict how long things will stick around. Since no one knows for sure, at Ethique we take the most conservative estimates – that’s 400 years, although some studies suggest plastics could take over 1000 years to break up.

It’s also worth noting that while plastic will break up into microscopic pieces given enough time, it will never decompose.

Let’s just get some terminology right – there’s composting, which is when you turn organic matter like paper, food and plants into usable fertiliser by putting it in a heap and letting it rot. That rot? That process is called biodegradation – and it’s all about microorganisms feeding on this material and, essentially, turning it back into soil. So, while wood, cotton and even (real) rubber will eventually be eaten by microorganisms, decompose and return to the soil, plastic won’t. It sits there forever. After a few hundred years your shampoo bottle will look like it's gone, but really it’s just been broken up into tiny, tiny pieces. Those microplastics are everywhere – we’ve even found them at the bottom of the deepest part of our oceans.

How do scientists work it all out?

Scientists use respirometry tests to measure how much CO2 is produced when bacteria do their work. A newspaper, banana peel or a plastic bag, for example, is put into what is essentially decomposition paradise. As microorganisms start breaking things down, they produce carbon dioxide – how much they produce can give us a guide on how quickly each item will break down.

For example, banana peels produce carbon dioxide (and methane) bonanza – that tells us they’ll take just a few weeks or so to break down in a compost heap. Put a plastic bag in there? Nothing.

No gas produced at all, which tells us the microorganisms are just chilling out in there – to those little guys, a plastic bag simply isn’t food.

So, left out in the wild, surrounded by microorganisms whose life’s work is to turn things back to soil, we know almost certainly that plastic won’t ever biodegrade.

But plastic does break up into bits – we know this because of accelerated life testing (ALT).

Basically, it condenses the life of an object to see how long it will last. This is used by manufacturers to test their products, and can also be used to study how plastic might break up. ALT uses a few processes to mimic the impact of heat, humidity, sunshine, pollution and other corrosive elements over a product’s lifetime.

UV degradation (sunlight) is what affects plastic. Different types of plastic behave differently, but in general it’ll become brittle, change colour, look chalky and eventually crack. Give it enough time in the sunlight and air, and plastic will break up as the polymers – the bonds – in the plastic are destroyed. So, yeah, it’ll all fall apart, but the pieces, those microplastics, remain in our environment.

That process is already well under way – every year, we pour 8 million tonnes of plastic into the sea. It’s exposed to the elements and broken up into microplastics, which are now found in every organism sampled (including microscopic plankton). It’s killing everything from seabirds to whales, and now we know that we consume 50,000 microplastics every year. Yummy.

One thing we’re also not sure of? What happens to our world when it’s drowning in microscopic bits of plastic that will never biodegrade. It’s probably not good.

But plastic gets recycled!

Only 9% of plastic ever made, has ever been recycled.

Bad news I'm afraid. People talk about recycling all the time and assume that its the solution and people just need to sort their recycling properly for the problem to be solved. Unfortunately, this is not the case. Global recycling infrastructure is woefully under funded and it simply cannot keep up with the mountains of waste we produce each year.

Recycling is better than nothing (marginally), but it's the ambulance at the bottom of a cliff.

400 years to break up into micro plastics is a (terrible) best-case scenario.

Ideally, plastics won’t end up seeing the sun at all. The vast majority of what doesn’t end up in the water is sealed into landfill and forgotten about. The thing is, landfills are like time machines. Some are compacted, wrapped in concrete, then buried – nothing, especially not plastic, breaks down or decomposes. Even a landfill piled up and left in the open tends to compact in on itself and preserve things that would otherwise have broken down in weeks. So out of a landfill, the best-case scenario is 400 years until your bottle turns into damaging plastic dust. In a landfill, it will last much, much longer.

Oh, and most compostable plastics aren’t really compostable either – while some will decompose in commercial composting facilities, most won’t even do that. Even created from hemp or corn, the structure of these new plastics is still… plastic. If it’s plastic, what it’s made from makes absolutely no difference. The annoying thing is that there’s no legal definition for compostable plastics – manufacturers can claim it without really proving it.

Let’s ditch single use plastic!

So even in ideal conditions your plastic bottles, cutlery and cups will probably never, ever decompose. The microfibers in your clothing are now considered some of the worst offenders for putting plastic into our oceans. The most conservative estimates predict it will break down after 400 years – into something that’s arguably even worse. While recycling is a good last resort, the best way to tackle our plastic problem is to stop using it in the first place.

Three easy ways to lessen your plastic footprint on the planet:

Stop using single use plastics.
Ever. There is no need. Everyone knows by now that you should stop buying water in plastic bottles (which really is just about the stupidest thing you can do with your money too, if you have perfectly good tap water). Stop using disposable cutlery because you can't be bothered doing the washing up. Use a reusable cup, a reusable bag, a reusable straw (key there though is, that you've got to reuse them.)

Stop partaking in fast fashion.
The average piece of clothing is worn less than five times!! The fashion industry is the most polluting industry globally, after fossil fuels. The plastic microfibers in your clothing are now considered some of the worst offenders for putting plastic into our oceans. Buy fewer clothes, and buy them made from natural materials, like cotton, wool or hemp. Ask brands who makes theirs clothes too and if they pay decent wages with fair working conditions- the fashion industry has a despicable ethics human rights record.

Get loud. Around the world all we hear is doom and gloom. Don't be deceived. We can solve all our problems. Humans are incredibly inventive and adaptable and we have every chance of sorting the environmental mess out. But we lack leadership both from business and governments. So speak up. Attend protests, write letters, tell supermarkets to stop wrapping everything in plastic wrap, support ethical businesses, educate your friends (but don't preach... nobody likes being lectured.)

I'll end with my favourite quote which, though often used, is both fitting & inspiring.

"Never doubt that a small group of thoughtful, committed citizens can change the world; indeed, it's the only thing that ever has."Margaret Mead