Life Cycle Assessment and Recycling (C10.2)

Life Cycle Assessment (LCA)

An LCA evaluates the environmental impact of a product across its entire life span:

Four stages:

1. Extraction and processing of raw materials — mining, energy use, pollution.
2. Manufacture and packaging — energy use, waste, emissions.
3. Use — energy consumption, emissions during use.
4. Disposal — landfill, incineration, recycling, biodegradation.

LCAs consider: energy use, water use, CO₂ emissions, land use, toxic emissions, waste.

Limitations of LCA:

• Some impacts are difficult to quantify (e.g. habitat disruption, noise pollution).
• Selective use of data can be biased (companies can commission favourable LCAs).
• Assumptions about use patterns introduce uncertainty.
• Can be expensive and time-consuming to produce.

Using LCAs to compare products

Example: LCA of a plastic bag vs a cotton bag:

• Plastic bag: low energy to manufacture; not biodegradable; harms marine life if littered.
• Cotton bag: high water and land use during cotton farming; biodegradable; must be reused >100 times to have lower overall impact than plastic bag.

Reducing use of resources — the 6 Rs

Reduce: use less material in the first place.
Reuse: use items multiple times before discarding.
Recycle: process waste material into new products.
Repair: fix broken items rather than replacing.
Refuse: decline unnecessary items/packaging.
Rethink: redesign products for longer life/easier recycling.

Recycling specific materials

Aluminium: particularly valuable to recycle — ore extraction is very energy-intensive (electrolysis), so recycling saves enormous energy and cost.

Common exam errors

1. Thinking LCA is only about CO₂ — it covers all environmental impacts across the full life cycle.
2. Saying recycling always saves energy — depends on the material and process; some recycling is energy-intensive.
3. Forgetting that LCAs can be biased depending on who commissions them.