Life cycle assessment and recycling
Life cycle assessments
A measures the environmental impact of a product at each stage of its life:
- Extracting and processing the raw materials
- Manufacturing and packaging
- Use and operation during its lifetime
- Disposal at the end of its life
At each stage, an LCA considers the use of water, resources and energy sources, and the production of waste and pollution.
Key terms
Plastic bags vs paper bags
| Stage | Plastic (polythene) bag | Paper bag |
|---|---|---|
| Raw materials | From (finite); fractional distillation, cracking and polymerisation all need energy | From trees (renewable), but processing timber uses lots of energy |
| Manufacture | Uses less energy; little waste | Uses more energy and water |
| Use | Strong; can be reused many times | Weaker; usually used only once or twice |
| Disposal | Doesn't biodegrade, so harms wildlife if littered; can be recycled | and is easily recycled |
Key terms
Limits of LCAs
Some parts of an LCA are easy to measure, such as the energy and water used.
Others are hard to give a number to, such as how harmful a pollutant is. These need , which means LCAs are not completely objective.
LCAs can also be misused. A selective or shortened LCA that leaves out some stages or impacts can be used to support a company's claims, for example in advertising.
Key terms
Reduce, reuse, recycle
Reducing what we use, reusing products and materials cuts the use of limited resources, energy, waste and environmental impact.
- Glass bottles can be washed and reused, or crushed and melted to make new glass.
- Metals are recycled by melting and recasting. Scrap steel can be added to iron from a blast furnace, so less iron ore is needed.
Pros: saves finite resources and energy; less mining and less landfill; often fewer greenhouse gas emissions.
Cons: collecting, transporting and sorting materials costs money and uses energy; some materials can only be recycled a few times, or must be very pure.