Downstream refers to the forward direction in a product life cycle, moving towards the use phase and eventual disposal of the product. This term describes the stages that occur after the production of a product, encompassing distribution, consumer use, and end-of-life treatment activities.
According to ISO 14040 and 14044, a complete product life cycle includes raw material acquisition, production, use, and disposal. Downstream stages represent the latter portions of this continuum, where products fulfil their intended function and ultimately reach their end of life.
The downstream perspective is particularly important when assessing products with significant use-phase impacts, such as energy-consuming appliances, vehicles, or products that generate emissions during use. For many products, downstream impacts can dominate the overall environmental footprint, making thorough analysis of these stages critical for identifying improvement opportunities.
Downstream considerations also include the distribution and transportation of products to end users, packaging waste management, consumer behaviour during product use, maintenance and repair activities, and end-of-life scenarios including recycling, energy recovery, or final disposal. Each of these stages can contribute substantially to the total environmental burden of a product system.
The term "downstream" stands in contrast to "upstream" or "indirect", which refers to the backward direction in the life cycle towards raw material extraction and production. Together, these directional terms help LCA practitioners and decision-makers communicate clearly about which portions of the product life cycle are being considered in an analysis or intervention strategy.
