Why land use matters
Land supports the production of food, fibres and raw materials, while providing essential ecological functions. The conversion of natural ecosystems, long-term occupation and land-management practices can affect biodiversity, carbon storage, soil structure, erosion and water availability.
In Life Cycle Assessment (LCA), the land-use impact category seeks to represent some of these pressures across a value chain. It is not simply a matter of measuring area: duration, previous and subsequent land use, and local conditions can all influence potential impacts.
Occupation and transformation
Two aspects are commonly distinguished. Land occupation represents the use of a given area over a period of time—for example, hectares of agricultural land occupied for one year. Land transformation represents the conversion from one land-use type to another, such as replacing natural vegetation with agricultural land.
Changes may be direct, when they occur in the area associated with the process under study, or indirect, when they result from changes elsewhere in a supply chain or market. Identifying and quantifying these relationships depends on the data and modelling choices.
Results depend on the method
There is no single universal land-use indicator across all LCA methods. ReCiPe 2016, for example, includes indicators for occupation and transformation. The European Union’s Environmental Footprint method uses a soil-quality index that aggregates properties such as biotic production, erosion resistance, mechanical filtration and groundwater regeneration.
Results from different methods should therefore not be compared directly without checking the impact categories, indicators, units, system boundaries and assumptions. Geographical data quality and regional representativeness are particularly important.
What to consider in an assessment
A consistent assessment should document location, area and occupation period; distinguish occupation from transformation; identify previous and current land use; and justify the selected impact-assessment method. Regionalised data and transparent scenarios should be used whenever possible.
Land use complements other impact categories. A decision that reduces pressure on land may, for example, increase energy or water consumption. Interpretation should consider the results as a whole and avoid shifting impacts from one life-cycle stage or category to another.