Life Cycle Assessment

Life cycle assessment (LCA) is a standardized set of procedures used to quantify the inputs, outputs, and potential environmental impacts of products or systems across their entire life cycle. LCAs promote the redesign and responsible design of products and processes to reduce harm to the environment.1 The life cycle is understood as beginning with the extraction and processing of raw materials; then manufacturing, transportation, and distribution; use and maintenance; and finally, recycling and disposal. An LCA provides an assessment of the waste produced, the energy and materials used, and the environmental burdens caused by those products or systems. The first step is to define an LCA’s goals and scope. Next, a life-cycle inventory is created, with the energy and material inputs and outputs, and the environmental releases at each phase. This information is analyzed in relation to its impacts on human health and the environment, and a final analysis offers proposals for reducing energy, materials, or environmental impacts at each phase of the life cycle.2

LCA can help industry professionals make environmentally sound decisions about products and materials, as well as minimize regulatory and production costs, and protect human health and equitable economic distribution.3 LCA can be applied to products, buildings, and production systems. It is used internationally, as it is governed by the International Organization for Standardization (ISO) under ISO 14000, the series of standards related to environmental management.4 LCA is used in government policy, strategic planning, marketing, consumer education, architecture, and product design. Many labeling and consumer education programs around the world also use LCA.5 While it is a standardized system, decision-makers may apply it in different ways, with different conclusions and results.6

LCA was designed using Life Cycle Thinking (LCT), a systemic framework that expands the vision of production and manufacturing to encompass a product’s entire life cycle, as well as its environmental, social, and economic impacts. This holistic approach is the basis for many sustainability strategies because it is effective in reducing negative impacts throughout the product’s life cycle while also maintaining or improving profits.7

There are several LCA variants, which focus on different phases or processes in the life cycle. An LCA might study a reduced life cycle, such as cradle to gate (only production and manufacturing), or focus on particular processes or inputs and outputs. In the building industry, LCAs tend to be process-based.8 An Environmental Life Cycle Assessment (E-LCA) prioritizes the evaluation of environmental performance, isolating the extraction of materials and resources, including energy, and any environmental releases throughout the life cycle. An E-LCA evaluates the impact of these processes on various environmental categories, including climate change, human and eco-toxicity, ionizing radiation, and resource base deterioration. Conversely, the Social Life Cycle Assessment (S-LCA) exclusively examines the social and sociological impacts along the life cycle. These LCAs can be used on their own or in combination with others. Another variant, the Life Cycle Sustainability Assessment (LCSA) is more holistic, examining not just environmental, but also social and economic impacts across the life cycle. LCSA is a tool that helps stakeholders design more sustainable products and means of production by providing a more comprehensive understanding of the related impacts.9

  1. The Environmental Protection Agency: Design for the Environment Life-Cycle Assessments
  2. American Institute of Architects: Building Life Cycle Assessment in Practice
  3. The United Nation Environmental Program’s Life Cycle Initiative
  4. American Institute of Architects: Building Life Cycle Assessment in Practice
  5. The LCA Textbook
  6. The United Nation Environmental Program’s Life Cycle Initiative
  7. American Institute of Architects: Building Life Cycle Assessment in Practice

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