Indirect refers to activities and impacts occurring backwards in the life cycle relative to the Activity being studied. This directional term describes movement towards the earlier stages of a product system, specifically towards raw material extraction and the production of inputs.
In Life Cycle Assessment, understanding the indirect dimension is crucial for comprehensive environmental analysis. When studying a particular activity, such as manufacturing a finished product, the indirect effects encompass all the upstream processes required to supply that activity. These include the extraction of raw materials from nature, the processing of these materials into intermediate products, the production of energy inputs, the manufacturing of capital equipment, and the transport of materials between facilities.
The concept aligns with the fundamental principle of LCA that environmental burdens do not occur in isolation at the point of production or consumption, but rather accumulate throughout the entire supply chain. Indirect impacts often constitute a substantial portion of a product's total environmental footprint, particularly for products with complex, multi-tiered supply chains.
ISO 14040 and ISO 14044 require systematic consideration of these upstream processes when defining system boundaries for Life Cycle Inventory analysis. The extent to which indirect activities are included depends on the goal and scope of the study, though consequential LCA approaches place particular emphasis on identifying which indirect activities will change as a consequence of decisions about the studied activity.
The term "upstream" is used synonymously with indirect, both referring to the same backward direction in the product life cycle. This contrasts with "downstream" or "direct" impacts, which occur forwards in the life cycle towards product use and end-of-life treatment.
