Stroll through any aisle in the grocery store today and it won’t take long to find products that claim to be sustainable. Some brands might profess how much energy was offset to make a product, while others may point to recycled content or natural ingredients.
But what do assertions by a business like these mean in real terms? How exactly is sustainability measured?
One of the most common methodologies for quantifying sustainability is life cycle assessment (LCA). An LCA is a systematic analysis of environmental impact over the course of the entire life cycle of a product, material, process, or other measurable activity. LCA models the environmental implications of the many interacting systems that make up industrial production. When accurately performed, it can provide valuable data that decision-makers can use in support of sustainability initiatives.
Read on for a basic introduction to LCA: What it is, how one is performed, and why it helps businesses, policymakers, and consumers make more informed decisions when it comes to supporting sustainability.
What are the benefits of doing an LCA?
The results of an LCA can help businesses, policymakers, and other organizations make more informed decisions to advance towards sustainability. It provides critical data that can support the following:
- process and product-design improvement
- marketing (e.g., backing up environmental claims or meeting consumer demand for green products)
- hot-spot analysis to facilitate continuous improvement
- third-party verification or certification
- method for quantifying key environmental impacts (e.g., greenhouse gas, carbon emissions, water use, and energy consumption)
- goal-setting for climate-change and other sustainability policies
What is life cycle thinking?
Understanding what an LCA is and how it works means thinking about industrial products and activities in terms of a life cycle.
It might seem odd to think about inanimate objects like a toaster or how a factory uses water as having a life cycle, but that’s exactly what LCA requires us to do. Every product, whether something as simple as a plastic cup or a highly designed electric car, is “born,” lives a “life,” and, when it is no longer useful, its life ends.
The life cycle that describes most manufacturing today is as follows:
- material extraction
- production
- packaging and distribution
- use
- end of use
- waste treatment or recovery
A product’s life cycle is not unlike a living thing’s: Natural resources (energy, materials, and water) are used while wasted material, energy, and emissions are created. This happens at different points throughout an entire lifespan, resulting in environmental impacts, all ranging in severity.
The life cycle above reflects a linear model of production, also known as a cradle-to-grave life cycle. An LCA can also account for other models of life cycles, such as cradle-to-cradle. This describes a circular economy, where the end-of-life phase feeds directly into a new life cycle, often through a value retention process like remanufacturing.
The circular production model
Whatever the economic model, an LCA is a tool for identifying or comparing the environmental impacts of a product or industrial activity by quantifying all material flows and assessing how they interact with the natural environment.
Life cycle stages. Source: U.S. Environmental Protection Agency (1993)
How is environmental impact measured?
Sustainability can seem like an abstract idea. An LCA helps to make it concrete and actionable through the scientific measurement of environmental impacts.
Industrial activity interacts with the environment in many ways. Some of these are immediate, while others may occur far from the company’s actual location, thanks to the reach of global supply chains. Industry, in all its varieties, draws upon many activities and processes—diverse resources are consumed along the way as different substances are emitted. An LCA helps to determine to what extent these material exchanges with the environment are detrimental to both natural ecosystems and human health.
When an LCA is performed, a practitioner will set metrics to quantify the different inputs (e.g., energy, water, resources, land) and outputs (e.g., emissions, wastes, products) that occur throughout the life cycle of an industrial process, technology, or commodity. It allows an assessor to map flows of energy, resources, and materials in and out of a system. These are objective measurements, tracking distinct quantities like volume, mass, or weight. They are collected as part of the life cycle inventory (LCI).
The LCI data is interpreted later in the study, during the life cycle inventory assessment (LCIA), to represent actual impacts on the environment or human health. For example, a certain volume of petroleum may be used to produce one plastic fork. This is recorded in the LCI. In the LCIA, this measurement is used to calculate how much this contributes to global warming.
Environmental impact categories
Every LCA sets out specific environmental impact categories that guide the direction of the LCIA. There are many different LCA methods and each utilizes a unique set of categories. However, there are general types found across all methods, though different wording and metrics may be used.
- climate change (contribution to global warming)
- acidification (contribution to the occurrence of acid rain)
- energy (cumulative energy demand and loss throughout a life cycle)
- eutrophication (the release of nitrogen and phosphorous, which leads to algal blooms)
- radiation
- land use
- air pollution
- resource depletion
- water use
- ecotoxicity (the release of toxins that are harmful to life)
Hotspots
While evaluating the environmental impacts of a product or industrial activity, an LCA serves to identify hotspots. These are points in the life cycle that have significant negative impact on the environment. Most often, resolving hotspots becomes the cornerstone of the sustainability plan based on a complete LCA.
Who performs an LCA?
An LCA may be done by a certified professional (LCACP), but certification is not required. Many engineers within different industrial sectors regularly perform LCAs and related modeling to further sustainability efforts. In the United States, LCACP certification is awarded by the American Center for Life Cycle Assessment (ACLCA).
How is an LCA performed?
The four key steps of LCA
The approach that would become LCA first emerged in the 1960s and 1970s, though there was little consistency in how such analysis was practiced. However, by the 1990s, the international scientific community made steps to standardize LCA. This led to a commitment by the International Organization for Standardization (ISO) in 1994 to create today’s LCA standards including guidelines and the principles and framework.
In 2002, the United Nations Environmental Programme (UNEP) and the Society for Environmental Toxicology and Chemistry (SETAC) moved to advance LCA through the creation of the Life Cycle Initiative. By 2005, the European Union, the United States Environmental Protection Agency, and many other government bodies had implemented policies promoting the use of LCA as part of sustainability initiatives.
Today, LCA is a methodology used by scientists, policymakers, and business leaders to set sustainability goals. It is often used in conjunction with other well-known tools, like material-flow analysis (MFA).
The ISO standards describe the principles and full framework for conducting an LCA. The assessment is broken down into the following four phases:
- goal and scope definition
- life cycle inventory analysis (LCI)
- life cycle impact assessment (LCIA)
- interpretation
Each step is described in greater detail below. Highlights from an actual LCA performed by the New York State Pollution Prevention Institute (NYSP2I) are also included in order to better illustrate each phase of the study.
Step 1: Goal and scope definition
Accounting for all the many potential impacts of an entire manufacturing process would require an incredible amount of time, data, knowledge, and resources—there are limits to the breadth and data quality of any analysis, after all. An LCA analyst makes this task manageable by first clearly defining an LCA’s goal and scope.
Functional units, system boundaries, and limits to the analysis are set to outline where in the life cycle the study begins and where it ends, and to identify what processes within the technical system will be assessed. A functional unit is the basis for the study. It is a measurement of production or output against which impact indicator metrics are normalized.
The scope of an LCA is determined by the number of life cycle stages and impact categories that will be assessed. One assessment might take in just one life cycle stage and one impact, making it very targeted and focused. Another might be far more comprehensive in scope, addressing an entire life cycle across many impact categories. Between these two poles stand many possibilities.
A business is more likely to prefer an LCA that is narrow in scope—it requires far less time and resources to perform, and it’s more likely to lead to actionable results. However, its limited range often means turning to supplemental data sources and estimated measurements to fill in gaps. A truly comprehensive study, as an attempt to model all of a manufacturer’s activities, would generate a complex set of data that would not lend itself as easily to practical interpretation. Yet this richer data is attractive to researchers and policymakers because it can help them understand real-world conditions more accurately.
