How Life Cycle Assessment Reveals Hidden Environmental Impacts of Everyday Products

Life Cycle Assessment (LCA) is a comprehensive method for evaluating the environmental impacts of a product, process, or service throughout its entire life cycle, from raw material extraction to disposal.

LCA's Four Stages

LCA analysis typically consists of:

Goal and Scope Definition : Define the purpose and system boundaries, e.g., whether to assess the whole product life cycle or a specific stage.

Inventory Analysis : Collect data on all inputs (resources, energy) and outputs (emissions, waste) associated with the life cycle.

Impact Assessment : Convert inventory data into environmental impact indicators such as Global Warming Potential (GWP).

Interpretation of Results : Analyze the outcomes and propose improvement measures.

Case Study: Milk Brand LCA

Goal and Scope Definition

The case examines a milk brand from dairy farming through consumer use and disposal, quantifying carbon emissions and water footprint.

Inventory Analysis

Resource consumption and emissions for each phase are:

Livestock feeding – Energy 2.5 MJ/L, Water 800 L/L, Carbon 0.8 kg CO₂e/L

Milk processing & packaging – Energy 1.2 MJ/L, Water 20 L/L, Carbon 0.5 kg CO₂e/L

Transport – Energy 0.3 MJ/L, Water 5 L/L, Carbon 0.2 kg CO₂e/L

Consumer use & disposal – Energy 0.1 MJ/L, Water 2 L/L, Carbon 0.1 kg CO₂e/L

Impact Assessment

Carbon emissions are summed to obtain the product's Global Warming Potential (GWP). Water footprint is calculated as the total water used across all stages.

Result Interpretation

The livestock feeding stage accounts for the largest environmental impacts, contributing 96.7% of total water use and 50% of carbon emissions, mainly due to feed demand, water consumption, and methane from enteric fermentation.

Optimization Suggestions

Adjusting feed composition (e.g., adding high‑fat feed) can reduce methane emissions; using biodegradable or recyclable packaging lowers impact in the disposal stage; and adopting electric or hybrid transport reduces energy use.

Additional data for ten common products:

Beef – 27 kg CO₂e/kg, 15,400 L/kg

Pork – 12.1 kg CO₂e/kg, 6,000 L/kg

Chicken – 6.9 kg CO₂e/kg, 4,300 L/kg

Milk – 1.3 kg CO₂e/L, 1,000 L/L

Rice – 2.7 kg CO₂e/kg, 2,500 L/kg

Wheat bread – 0.9 kg CO₂e/kg, 1,600 L/kg

Chocolate – 19 kg CO₂e/kg, 17,000 L/kg

Coffee – 3.5 kg CO₂e/L, 1,120 L/L

Cotton – 2.1 kg CO₂e/kg, 10,000 L/kg

Paper – 1.2 kg CO₂e/kg, 2,700 L/kg

Limitations and Future Development

LCA faces several limitations: it heavily depends on data quality, regional data variations can cause uncertainty, current models focus on common impacts (e.g., global warming, acidification) and may overlook regional or long‑term issues, and differing system boundaries affect comparability.

Integrating LCA into everyday decisions helps assess resource use and emissions, choose low‑carbon products, optimize processes, and promote sustainable lifestyles.