75. Life Cycle Assessments (LCAs)
1. What is a Life Cycle Assessment?
A Life Cycle Assessment (LCA) is a process used to assess the environmental impact of a product across its entire "life." There are four main stages:
Extracting and processing raw materials: Impact of mining, cutting down trees, or drilling for oil.
Manufacturing and packaging: Energy use, pollution release, and waste production during the creation of the product.
Using the product: Damage done during its lifetime (e.g., car emissions) and how long it lasts.
Disposing of the product: Impact of landfills, incineration, and the energy used for transport to disposal sites.
2. Comparison: Plastic vs. Paper Bags
Stage | Plastic Bags | Paper Bags |
Raw Materials | Crude oil (finite resource). Requires fractional distillation. | Wood from trees. Can lead to habitat loss. |
Manufacturing | Hydrocarbons are cracked and polymerized. Low energy compared to paper. | Timber is pulped and soaked. Requires lots of energy and produces waste. |
Usage | Can be reused many times. | Usually single-use. |
Disposal | Not biodegradable. Takes up landfill space or harms wildlife. | Biodegradable and non-toxic. |
3. Limitations of LCAs
While LCAs are useful, they have several significant drawbacks:
Difficulty in Quantifying: It is often impossible to track and quantify every single step and gram of pollution in a complex manufacturing process.
Subjective Comparison: It is hard to compare different types of environmental harm (e.g., is lung disease from particulates worse than global warming from CO2?).
Bias and Manipulation: Because LCAs are complex, they can be manipulated by companies to highlight positive aspects for advertising, which is difficult for the public to detect.