The life cycle of your polyester T

Many of us are now dressed head to toe in plastic.

A textile derived from the same non-renewable source as takeaway containers, has grown to make up more than half of the clothes bought in Australia.

Polyester is durable, cheap, and dries quickly. It's also easy to print patterns on.

It's commonly used by itself or as a blend with other textiles. It's used for gym clothes and sports uniforms, party dresses, work attire, and many cheap fast fashion items.

And every purchase is taking an environmental toll.

One Australian study by RMIT found a single 100 per cent polyester T-shirt has a carbon footprint — from creation through to when you dump it in the bin — equivalent to 20.56 kilograms of CO2 emissions (CO2e).

That's equivalent to driving 140 kilometres. Buy just six tops, and that gets you all the way from Melbourne to Sydney.

So, what's involved in getting a T-shirt from a fossil fuel, to the one you might be wearing right now? Here's its journey along the supply chain.

Our polyester top starts off as crude oil.

It's derived from petroleum: a non-renewable fossil fuel.

Just getting this out of the ground or ocean has well-known impacts on the planet, including air and water pollution.

This petroleum then goes through a process called polymerisation to turn it into semi-crystalline plastic pellets called polyethylene terephthalate (PET). That's the same stuff your plastic bottle is made from.

To make the PET for just one polyester T-shirt, you need 7.6 kilowatt hours of energy and that will emit 5.95kg of CO2e, according to a 2018 study by Australian researchers at RMIT.

This makes PET production one of the most energy intense stages of our T-shirt's life cycle.

To make polyester, PET pellets are then fed through a machine with other agents, including spin finish oil, sodium hydrosulphite and acetic acid.

Some researchers describe this industrial process as like shoving melted plastic through a shower head.

At the end, you get a type of spun yarn.

This spinning process uses a lot of energy. Our T-shirt requires 5.32kWh of energy to be spun into something resembling your final fashion item.

That's not counting other environmental side effects, such as water and chemical usage during the fabric's dyeing process.

The dyes used in textile production can pollute waterways with toxins and carcinogens, including chromium.

It may be no surprise then that the textile industry is recognised as one of the world's biggest polluters.

Now our fossil fuel is starting to resemble something a little closer to a garment. It is a textile that can be cut up and sewed.

Few garments are made in Australia anymore.

A garment's country of origin makes a big difference to its final carbon footprint, according to data given to ABC News by Carbonfact, a tech company that helps brands track their carbon footprint.

A polyester T-shirt made in Vietnam emits 25 per cent less CO2e than a top made in India, Carbonfact data shows.

That's because India is far more reliant on coal for its energy.

China and Bangladesh fall in the middle.

"The carbon intensity of the electric mix of the country where those processes happen impact the final number," Carbonfact's co-founder Martin Daniel says.

You also get leftover fabric when you cut patterns. This discarded textile waste can then end up in landfill or incinerated.

There is also a human toll. It's now been a decade since one of the worst garment factory disasters in history killed 1,100 people in Bangladesh.

Human rights groups like Oxfam warn that many Australian brands still aren't doing enough to protect workers in their supply chains.

Now we have something that is ready to sell.

Distribution requires plastic slips, boxes, wrapping, garment tags and lots of transport.

Clicking express post? Next time you pay for this extra service to get an item by the weekend, you may want to consider its far higher environmental impact.

Your polyester T-shirt will be responsible for 120 times more in CO2e emissions if it is flown from China to Australia, rather than brought here by sea freight, Carbonfact data shows.

Many brands overall have a long way to go with disclosing their environmental impacts.

ABC News approached a range of major brands that sell polyester T-shirts in Australia, including Uniqlo, Kmart, Asos, Shein, and Rebel Sport.

None replied with breakdowns of the carbon or environmental footprint of their items.

So you've got your new polyester top!

We hope you treasure it after all it has gone through to get to you.

You might be surprised that this next stage of its life cycle with you will be one of its most environmentally intensive. That's because of the water and energy you'll use to care for it.

That same 2018 study by Australian researchers at RMIT modelled this stage of a polyester T-shirt's life cycle.

They estimated 50 washings during its one-year life span with regular use of tumble dryers.

This would contribute to nearly a third of its carbon footprint overall, they found, or 6.25kg of CO2e emissions.

The researchers also found that a T-shirt washed 50 times in its lifetime would require 3.11kWh of energy and 135 litres of water.

The production of the required detergent alone would lead to 2.5kg of CO2e.

As well as using lots of energy, every time you wash that polyester top, it will shed tiny particles of plastic.

This problem, known as microplastics, is now a major threat that is choking our animals and ecosystems.

A third of the microplastics being released into our oceans and waterways are from synthetic textile shedding, one study from 2017 found.

Washing your polyester top less may help. Polyester is notoriously non-breathable, however, so you may end up a bit smellier.

If you're in a sunny and warm place, then line-drying should be your default, says Queensland University of Technology fashion and design lecturer Dr Zoe Mellick.

Microplastics protector bags are also an option to prevent them leaching out into the environment.

If this article has unsettled you, there are things you can do about it.

Firstly, before you click purchase or take an item to the register, sustainability experts urge you to contemplate: do you really need this?

Could you get this item second-hand instead?

Australians buy on average 56 new garments a year or 14.8kg of textiles. That makes us one of the biggest consumers of fashion in the world — and we're throwing away a lot of it.

In Australia, 6,000kg of clothing and textiles are dumped in landfill every 10 minutes.

"Synthetic fibres [like polyester] take a lot longer to decompose," Dr Mellick says.

"Some studies have said between 20 to 200 years to decompose.

"We've got to be looking for things that are durable en masse for as long as possible."

It might also be tempting to buy garments that claim they're better for the planet, such as recycled polyester or synthetic replacements.

Be warned: fashion is rife with greenwashing, says the consumer watchdog ACCC.

You might also think you're doing the right thing if you put your polyester T-shirt in the recycling bin.

Planet advocate and prankster Craig Reucassel takes a deep dive into Australia's waste crisis to sort the facts from the PR spin, tracking down everyday solutions to help all of us do our part in the war on waste.

While it might be made from PET, polyester is often blended with other textiles, which makes it difficult to recycle.

"Consumers should be more aware of their use," the lead author on the RMIT 2018 study, Shadia Moazzem, told ABC News.

"Consumers just buy, wear it a few months and dispose of it."

Lastly, treasure what you have. Learn to mend garments before chucking them, and use ones beyond repair as rags.

After all, one simple polyester T-shirt has gone through a lot just to get to you.