A life-cycle assessment (LCA) measures the total effect of a material or product on the environment, from the start of its life to the end. At each stage it records the use of resources, such as energy, water and raw materials, and the impact on the environment, such as waste, pollution and carbon dioxide released.
There are four stages to consider:
- making the materials from raw materials, and the process used to make the product
- the use of the product
- transport of the product
- disposal at the end of its life, for example landfill, incineration or recycling
Transport happens between the stages, so it uses fuel throughout. Some impacts are easy to measure, such as the energy used or the mass of waste. Others, such as damage to wildlife habitats, are harder to put a number on, so an LCA often needs some judgement.