What’s the Purpose of LCA, Anyway?

Author: Lise Laurin, CEO & Founder

In our November Brown Bag Webinar, Rafael Auras, my go-to for sustainable packaging expertise, spoke about the importance of boundary conditions in order to capture the system-wide impacts of packaging. He talked about how failure to do so may end up with low impact packaging that doesn’t actually do its job of protecting the product. 

If we only optimize for low packaging impact without ensuring that the packaging still protects the product, we risk increasing the system-wide footprint instead of reducing it. When the product being protected has a much higher environmental impact than the packaging itself, as is the case with foods like meat and high-tech items like electronics, inadequate protection can lead to product loss — and the resulting footprint is far greater than the savings from lightweighting. 

Too often, Life Cycle Assessments (LCAs) are performed based on a set of rules without consideration of the consequences of the results.

Which leads me to the question: What is the purpose of LCA, anyway?

While the literal answer may vary, most of us who conduct or use LCAs do so with the intention of reducing real-world environmental harm. For LCA to achieve that purpose, the results must influence action. Sometimes that action is choosing a lower-impact product. Sometimes it is identifying and reducing a hotspot within a supply chain. But in every case, the practitioner should consider what behavior the study will drive and whether that behavior leads to a lower-impact system overall.

Let’s consider packaging LCAs as an example. If the study ignores product losses, it may unintentionally encourage packaging designs that increase damage to more of the product – leading to higher impacts than the lightweight package is reducing. Similarly, in the automotive market, ignoring the fuel efficiency benefits of a lightweight car part may reduce its adoption rate in the market. 

The result: a missed opportunity for meaningful impact reduction.

Another example of this dynamic is our treatment of recycled materials. In LCA, allocation refers to the method used to divide environmental burdens and benefits among product systems that share processes or material flows. Two commonly applied approaches in recycling systems are the cut-off method and allocation at the point of substitution.

Under the cut-off method, recycled materials enter the product system with no upstream environmental burdens — only the impacts associated with their processing are considered. This approach tends to incentivize the use of recycled materials, because manufacturers receive environmental credit for incorporating them. However, it provides comparatively less incentive to ensure that products are collected and recycled at end-of-life.

In contrast, allocation at the point of substitution assigns credit when recycled materials displace virgin production. This approach encourages recycling activity, because the environmental benefit is tied to the end of the first life. However, it can reduce incentives for manufacturers to use recycled feedstocks, because the environmental benefit is realized at the point of recycling, not at the point of use.

Both methods are valid, but they encourage different behaviors. For materials such as metals, which are efficiently recovered and re-entered into manufacturing loops, encouraging end-of-life recycling through the allocation at the point of substitution may be appropriate. For materials such as plastics and textiles, which are more likely to be landfilled or downcycled, strong incentives for the use of recycled content, as encouraged by the cut-off method, may be more critical for developing circular supply streams. Weidema’s market-based end-of-life modeling framework recognizes this by aligning allocation approaches with actual material markets and recovery dynamics (Weidma, 2003).

A related system-level consideration appears in the energy sector. Power Purchase Agreements (PPAs) — long-term financial contracts used to support renewable electricity generation — have been accepted within the GHG Protocol and, according to some, in LCA for many years. While PPAs do not trace physical electrons to specific consumption points, they have been demonstrated to accelerate the construction of new renewable energy infrastructure by reducing financial uncertainty and enabling project financing (Ebere J Onyeka, 2025). In other words, even if PPAs are not physically precise, they change the system in a direction aligned with environmental benefit. EarthShift Global examined this approach in collaboration with Eastman Chemical to assess an internal PPA (Prado et al., 2020).

This principle is now being explored in chain-of-custody accounting, an approach where environmental benefits are assigned based on financial support rather than physical tracking. This is particularly relevant in biobased, recycled, or chemically recycled material streams where feedstocks are blended and cannot be traced atom-by-atom. Our upcoming Brown Bag Webinar with Jason Pierce, a Technology Fellow in the Global Sustainability Division of Eastman Chemical, will further explore how chain-of-custody models influence LCA results, reporting, and market transitions.

A reviewer once suggested to me that the practitioner’s responsibility ends at providing results, leaving interpretation and decision-making entirely to the commissioner. I disagree. If we accept that the purpose of LCA is to enable meaningful environmental improvement — not merely to quantify impacts — then interpretation, contextualization, and guidance are essential components of high-quality LCA practice. Practitioners must consider the broader system, the behavioral consequences of their modeling choices, and the likely impact pathways of the recommendations they provide.

The purpose of LCA is not simply to measure environmental impact.

The purpose of LCA is to inform decisions that reduce it.