The International Organization for Standardization (ISO) recommends the use of life-cycle assessment (LCA) to better comprehend and reduce environmental impacts related to manufactured products and services offered to our society. The principles of LCA are presented in the international standard ISO 14040; however, the implementation of the standard is not simple, and a couple of studies have addressed the existing limitations (Khan et al. 2002; Ross and Evans 2002).
One fundamental question is how to characterize a given environmental insult and how to select an appropriate metric to evaluate and minimize their impacts. This problem stem from the multiplicity of environmental insults caused by human activities, which are difficult to compare using a single approach. Moreover, most environmental problems have an intrinsic temporal dimension since environmental impacts persist in the environment for years and in some cases for generations. This yields sustainability concerns, which demand frameworks that allow the comparison of outcomes over time.