What Is the Life Cycle Assessment?

And how does it promote sustainability?

Sustainable world concept.
Petmal / Getty Images

The Life Cycle Assessment, or LCA, is a measurement of a product's impact throughout its life cycle. While initially an energy analysis, this tool has evolved to cover the environmental and social impact of products.

Early research on the LCA began in the late 1960s and early 1970s. These studies looked at energy requirements amidst growing concern for resource and energy efficiency, pollution control, and waste. In the 90s, scientists around the world began coordinating activities surrounding these concerns. This resulted in complementary methods and procedures from both the Society of Environmental Toxicology and Chemistry (SETAC) and the International Organization for Standardization (ISO). These programs made way for the LCA to be adopted into modern policy and legislation, not just within individual companies but across the world.

A Product's Life Cycle

Infographic of the four stages of a product's life cycle.

Treehugger / Sharmon Lebby

There are several ways to measure the life cycle of a product. The most basic of assessments will account for energy input and output and environmental impact at each stage. The LCA begins with the extraction of its raw materials and ends with a product's disposal or reuse. In general, a product's life cycle can be broken down into four main parts: raw material extraction, production, use, and end of life.

Raw Material Extraction

Where raw materials are coming from and how they are extracted largely contribute to the state of a product's life cycle. This part in the cycle includes the collection, creation or acquisition of materials from the environment or other means. Whether it is a crop, minerals, or fossil fuels, this would entail the resources and energy required to grow and harvest it or extract it from the earth. Also included would be the impact on the surrounding ecosystems.


This stage is a multi-step process, which includes the processing of the raw materials, manufacturing and assembly of the product, packaging, and transportation. When an assessment is ended at this point, it's called cradle to gate—a method more common in business to business assessments, where the use phase is bypassed completely.

Consumer Use

How a consumer will use the product can be an important determinant in the life cycle. Though it is believed that this phase is the most important in terms of impact, consumer behavior has been one of the least studied areas within the general field of life cycle analysis. For instance, more water will be used during the time a consumer has a shirt than the water used to produce the shirt. This lends to the argument that this portion of a product's life cycle is a significant element of the assessment.

End of Life

This is the most focused-on stage of the assessment because of the known effects of waste on human health and the environment. The focus on the end of life stage is also responsible for assessments such as cradle-to-grave and cradle-to-cradle. Cradle-to-grave indicates an object that is made and then disposed of when no longer used. It is this method that creates waste. In a cradle-to-cradle model, the product is able to be reused in some fashion eliminating waste. While cradle-to-cradle models aren't typical of the LCA, it's being considered more as sustainability is becoming increasingly integrated with the assessment.

The Phases of Life Cycle Assesment

Info graphic of life cycle assessment phases

Treehugger/Sharmon Lebby

There are four phases or steps of the LCA: goal and scope; inventory analysis of extractions and emissions; life cycle impact assessment; and interpretation. Each of these phases is part of a standard created by ISO to provide a strategic method to assess the life cycle.

Goal and Scope

Though it can be modified based on subsequent data, the goal and scope phase is considered particularly important as it defines the exact approach taken in the assessment. Procedures for this phase are loosely defined by the ISO to allow for variability. A few things to consider in this phase are performance, aesthetics, and the cost of the product. Together, these make up the functional unit. Also assessed would be system boundaries, exclusion of life cycle stages or inputs, and the selection of impact indicators and characterization factors.

Inventory Analysis

This is the phase where input/output data with regard to the system or product is gathered. This will included the necessary information to meet the goals defined in the goal and scope phase. This has been spouted as the most straight forward portion of the LCA. It is also one of the more time consuming. Because of this, a number of databases have been developed to provided resources to compile the needed data. One example, the U.S. Life Cycle Inventory (USLCI) Database, provides "individual gate-to-gate, cradle-to-gate, and cradle-to-grave accounting of the energy and material flows into and out of the environment that are associated with producing a material, component, or assembly in the U.S."

Impact Assessment

The Impact Assessment of the LCA adds to the data collected in the inventory analysis to better assess the possible environmental impact of a product. This step will involve choosing relevant impact categories, putting data from the LCI into the categories, and modeling these impacts. In addition some studies may want to sort, rank and weight the specific categories though generally only the first steps are done.


The last phase of the assessment is meant to use all gathered information to evaluate the accuracy of the data collected and whether or not the study's goals were met. The stated outcome should reflect the conclusions and limitations of the study as well as present relevant recommendations. The interpretation should project confidence in the study and relate results in a manner that is thorough and objective.

Impact on Sustainability

The LCA can be and has been used successfully in multiple industries. A Brazilian cosmetics manufacturer, for example, measured and managed the environmental impacts of its product using the LCA. Within the agri-food sector, the tool is used to determine the environmental footprint of various crops. It has also been used to assess the main contributions to the carbon footprint of a wool sweater.

Still, the LCA has its critics. One criticism is that it often doesn't account for human behavior, and there are multiple ways to assess it. However, it has been instrumental in creating environmental protection policy that could extend to the implementation of sustainability standards. With the proposal of the Social and Environmental Life Cycle Assessment (SECLA) in 1996 and other agencies eagerly embracing a blended standard called the Life Cycle Sustainability Assessment, it's likely that LCAs in one form or another will continue to be at the forefront of sustainability strategy.

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