A variable is a placeholder for an amount used in mathematical formulas within Life Cycle Assessment databases and models. Variables enable flexible and dynamic calculations by representing values that can change depending on specific conditions, scenarios, or input parameters.
In LCA databases and software, variables serve as essential tools for creating adaptable and reusable models. Rather than hard-coding specific numerical values into formulas, practitioners use variables to represent quantities that may vary across different contexts, time periods, or geographical locations. This approach enhances the modularity and maintainability of LCA datasets.
Variables are particularly important in modern LCA database structures, where they allow for parameterised modelling. For example, a variable might represent the efficiency of a production process, the energy consumption per unit output, or a characterisation factor in impact assessment. By using variables, LCA practitioners can easily update models when new data becomes available or when conducting sensitivity analyses to understand how changes in specific parameters affect overall results.
The use of variables aligns with the computational structure of Life Cycle Inventory databases, where mathematical relationships between inputs and outputs must be precisely defined. Variables can be combined in formulas using standard mathematical operations, enabling complex calculations whilst maintaining transparency about the underlying assumptions and data sources.
In database systems such as ecoinvent, variables may be defined as properties of exchanges, allowing them to be referenced in mathematical relations within the same dataset. This functionality supports the creation of sophisticated models that can automatically adjust to different scenarios without requiring manual recalculation of all dependent values.
