Sustainability, environmental impact and responsible design
Sustainability, environmental impact and responsible design is examined through life-cycle thinking, material choice, energy, waste and ethical responsibility.
Core rules
- The 6 Rs: refuse, reduce, reuse, repair, recycle, rethink. Recycling is usually lower priority than reducing material and extending life.
- Life cycle assessment (LCA) covers extraction, manufacture, transport, use and disposal; each stage has impacts.
- Embodied energy is the energy used to make a product; carbon footprint is the greenhouse gas emitted across its life.
- Design for disassembly uses reversible fasteners, material labels and fewer mixed materials.
- Circular economy keeps materials in use; linear "take-make-dispose" wastes them.
- Bioplastics are not automatically low-impact: growing, processing and disposal conditions matter.
Worked example
Compare a phone case in TPU, PLA and leather. TPU is oil-based but tough and long-lasting; PLA is plant-based but may not biodegrade in landfill and softens in heat; leather is a by-product but needs tanning and treatment. The LCA must include mass, energy, transport and likely disposal. A thin TPU case used for three years may have a lower impact than three short-lived PLA cases, even though PLA sounds "greener".
Traps
Equating "biodegradable" with "safe in landfill"; assuming recycled content means recyclable; ignoring transport and use-phase energy; choosing a material on one property only.