A Life Cycle Assessment (LCA) works by systematically mapping every stage of a product's existence and calculating the environmental burden at each step. Analysts identify all the inputs (raw materials, energy, water) and outputs (products, emissions, waste) at every stage.
The four stages form a chain: Raw Material Extraction → Manufacturing → Use Phase → End of Life. An LCA analyst assigns a numerical impact to each stage — for example, kg of CO₂ emitted, litres of water consumed, or area of habitat destroyed. These figures are then added across all stages to give a total "environmental footprint."
For example, a smartphone LCA reveals that mining rare earth metals (Stage 1) accounts for roughly 85% of the phone's entire environmental impact — more than manufacturing, the entire use phase, and disposal combined. Without an LCA, a consumer might assume most impact comes from charging the phone daily, which is in fact a minor contributor.
LCA is described as a "cradle to grave" approach because it starts at the very beginning (the "cradle" — extraction of raw materials from the earth) and ends at final disposal (the "grave" — landfill, incineration, or recycling). A "cradle to cradle" approach extends this further, where the end of one product's life becomes the raw material for another product, creating a closed loop.
This how it works covers How It Works: Tracking Environmental Impact from Cradle to Grave within Life Cycle Assessment for GCSE Chemistry. Revise Life Cycle Assessment in Using Resources for GCSE Chemistry with 22 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 3 of 17 in this topic. Use this how it works to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Life Cycle Assessment
What does LCA stand for in the context of environmental science?
State two factors that are measured during a life cycle assessment.