A characterisation model is a mathematical and scientific framework that describes the relationship between a Life cycle inventory analysis result and its subsequent Impact(s) as represented by the Impact category endpoint(s). This model is the basis of Life Cycle Impact Assessment, translating inventory data into environmental impact indicators.
The characterisation model connects the quantified elementary exchanges recorded during the Life Cycle Inventory phase with the potential environmental consequences of those exchanges. Whilst the inventory phase documents what enters and leaves the product system, the characterisation model explains how those flows affect the environment, human health, and natural resources.
ISO 14040 defines the characterisation model as describing a relationship between Life Cycle Inventory analysis results and impact category indicators. The model typically incorporates environmental mechanisms, scientific relationships, and quantitative factors that express how different elementary exchanges contribute to specific impact category endpoints. For instance, a climate change characterisation model would describe how various greenhouse gas emissions (the LCI results) contribute to radiative forcing and ultimately to global temperature change (the impact category endpoint).
These models vary widely in complexity and scientific rigour across different impact categories. Some, such as climate change models based on radiative forcing potential, are relatively well established with broad scientific consensus. Others, particularly for impact categories like biodiversity or land use, involve greater uncertainty and more complex cause-effect chains. Environmental mechanisms, which represent activities not performed by humans or managed systems, often play a key role in characterisation models, linking inventory results to their ultimate environmental endpoints.
The outputs from characterisation models are expressed through characterisation factors, which are derived from the model and applied to convert inventory results into common units of impact category indicators.
As Chief Operating Officer, Iris leads our organisational development and oversees day-to-day operations. Before joining 2-0, she worked in the biotechnology sector. As an LCA consultant, Iris has devoted her expertise primarily to the domains of sustainable agriculture and food production. She is dedicated to teaching LCA and is responsible for our educational efforts. Iris holds an M.Sc. in Biology – Biotechnology from the University of Copenhagen.
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Glossary terms are clearer once you have seen them applied. Our guide to what LCA is and how it works walks through the complete methodology: goal and scope, inventory modelling, impact assessment, and interpretation.
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