page_title: Life-cycle engineering
section_title: Quantifying Environmental Sustainability
hierarchical_section_title: Life-cycle engineering / Quantifying Environmental Sustainability
caption_attribution_description: English: Planetary boundaries according to the paper by Rockström et al. published in Nature in 2009. The red areas represent the estimated current state with the inner green circle being the estimated boundaries.
context_page_description: Life-cycle engineering is a sustainability-oriented engineering methodology that takes into account the comprehensive technical, environmental, and economic impacts of decisions within the product life cycle. Alternatively it can be defined as “sustainability-oriented product development activities within the scope of one to several product life cycles.” LCE requires analysis to quantify sustainability, setting appropriate targets for environmental impact. The application of complementary methodologies and technologies enables engineers to apply LCE to fulfill environmental objectives.
  LCE was first introduced in the 1980s as a bottom-up engineering approach, and widely adopted in the 1990s as a systematic ‘cradle-to-grave’ approach. The goal of LCE is to find the best possible compromise in product engineering to meet the needs of society while minimizing environmental impacts. The methodology is closely related to, and overlaps with, life-cycle assessment to assess environmental impacts; and life cycle costing to assess economic impacts.
context_section_description: The first step in completing LCA or LCE is determining the appropriate sustainability thresholds to use as environmental targets for the product system. The proposed Lyngby Framework for LCE is a combined top-down and bottom-up approach for LCE that uses targets based on planetary boundaries.  Planetary boundaries can be used to establish limits for the earth’s carrying capacity, defining upper thresholds for the environmental system.
  
  The IPAT equation [Impact = Population (or Volume) x Affluence (or Consumption) x Technology (or Consumption per Unit Produced)] is an accepted method for quantifying the impact of consumption.  LCE can be leveraged to manage total environmental impact by addressing the technology effect (single product and product life cycle) and the volume effect (anticipated volume growth as consumption and population increase) of product engineering. Impacts are considered within the context of technical boundary conditions to verify the feasibility of proposed solutions.
caption: An example of Planetary Boundaries
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