Curriculum · Textile Lifecycle
Lifecycle Lab
Time to put on a lab coat. We're going to compare four common garments side by side — a cotton tee, a polyester hoodie, a linen shirt, and a recycled fleece — and see which one really wins. 🧪
Garment 1: The cotton t-shirt
Material: 100% conventional cotton.
Water footprint: ~2,700 litres per shirt. Carbon footprint: ~5–7 kg CO2e per shirt. Microplastics: zero. End of life: biodegradable in months to years if uncontaminated, BUT most cotton ends up in mixed-waste landfills where it doesn't break down well. Lifespan: 1–3 years for fast fashion, 5+ years for higher-quality.
Verdict: low microplastic impact, big water and pesticide impact (cotton uses about 16% of all insecticides applied globally — the most of any single crop). Organic cotton (look for GOTS certification) cuts pesticide use to near zero but still uses lots of water.
Garment 2: The polyester hoodie
Material: 100% polyester (or 80/20 cotton-polyester for many fleece-style hoodies).
Water footprint: low at production (~70 litres for fibre), but ongoing pollution from microfibre shedding. Carbon footprint: ~5–10 kg CO2e — actually higher than cotton because petroleum extraction is energy-intensive. Microplastics: high. A hoodie may shed thousands of microfibres per wash. End of life: not biodegradable. Lasts 200+ years in a landfill. Lifespan: 3–10 years (polyester is durable).
Verdict: durable and dries fast, but the microplastic problem is real. Best for items rarely washed (raincoats, gym bags) — worst for items washed often (everyday hoodies, t-shirts, leggings).
Garment 3: The linen shirt
Material: 100% linen (from flax).
Water footprint: ~6–25 litres per shirt — a tiny fraction of cotton. Carbon footprint: ~2 kg CO2e — among the lowest of any common fibre. Microplastics: zero. End of life: fully biodegradable in months. Lifespan: 5–20 years (linen actually gets softer with age).
Verdict: linen is one of the most sustainable common fibres available. The downside? It wrinkles, costs more upfront, and isn't great for stretchy or athletic clothing. But for shirts, dresses, and bedding, it's the gold standard.
Garment 4: The recycled polyester fleece
Material: Recycled polyester (rPET), often made from old plastic bottles.
Water footprint: ~30 litres per garment (less than virgin polyester, much less than cotton). Carbon footprint: ~3–5 kg CO2e — about 30–50% lower than virgin polyester. Microplastics: still high. Recycled polyester sheds just like virgin polyester. End of life: still not biodegradable. Recycling once means another stop on the way to landfill. Lifespan: 5–10 years.
Verdict: better than virgin polyester but worse than linen, hemp, or recycled cotton. The microplastic problem isn't solved by being recycled. Use a Guppyfriend bag, wash cold, and treat it as a once-recycled material that's heading to landfill eventually.
Overall ranking (best to worst for the planet, roughly): Linen ≥ Hemp > Recycled Cotton > Organic Cotton > Recycled Polyester > Conventional Cotton > Virgin Polyester.
Key takeaways
- Linen wins overall — low water, low carbon, biodegradable, long-lasting.
- Conventional cotton is high-impact: 2,700L water and 16% of global insecticide use.
- Polyester (virgin or recycled) sheds microplastics in every wash, no matter what.
- Recycled polyester cuts carbon by ~30–50% vs virgin — but still pollutes oceans.
- Lifespan and washing behaviour often matter MORE than which fibre you picked.
Try this
Score your favourite outfit
Pick one outfit you wear often. For each piece, note the material. Use this lesson to estimate its water footprint, microplastic risk, and biodegradability. Give the whole outfit a 'planet score' from 1–10. Now think: which piece could you swap to raise the score the most?
Build a comparison chart
Make a 4-column table: cotton, polyester, linen, recycled polyester. Add 4 rows: water, carbon, microplastics, lifespan. Fill it in from this lesson. Stick it on your wardrobe. Next time you shop, you have an instant cheat sheet.
The wardrobe gap analysis
Count how many items in your wardrobe are pure cotton, pure polyester, blended, or other natural fibres (linen, wool, hemp, silk). Calculate percentages. Then ask: what would happen if you replaced your next 3 polyester purchases with linen or hemp? Estimate the water savings.
Which of these typically has the LOWEST overall environmental footprint per garment?
Linen wins on most metrics — low water (often under 25 litres per shirt), low carbon (~2 kg CO2e), no microplastics, and fully biodegradable. The main downsides are higher upfront cost and wrinkling. For everyday shirts, dresses, and bedding, linen is one of the most sustainable choices available.