5. Embodied Carbon of Surfaces: Inclusion of Surface Albedo Accounting in Life-Cycle Assessment

Albedo is an optical property of surfaces. The higher is the surface albedo, the higher is the amount of solar radiation that a surface scatters back to space.

During the last centuries, urbanization, deforestation, afforestation, and all the modifications of extended areas on Earth have produced a variation in local albedo giving rise to an alteration of the Earth’s energy balance. In the urban environment, the use of low-albedo building materials in the building envelope can exert an effect at different scales. Specifically, it can contribute to a higher request of energy for cooling the indoor building spaces in summer, since low-albedo surfaces absorb a higher amount of solar energy compared to high-albedo ones and it can also contribute to the urban heat island effect (i.e., an increase in urban temperature compared to the surrounding rural areas). In turn, the urban heat island might affect the building energy use for summer cooling and contribute to an energy imbalance that has an impact on climate change. While, in the last years, a growing number of studies have explored the effect of the employment of low-albedo materials in building envelopes on the cooling energy budget and on the urban heat island, the evaluation of the effect of urban surface albedo on climate change belongs to a recent and a still exiguous strand of research. Climate science teaches us that surface albedo can exert an effect on climate change; such effect can be translated in terms of carbon dioxide equivalents and included in the accounting of the embodied carbon of the use phase of a building. However, traditionally, the contribution of albedo of materials or components for the building envelope is often disregarded in life-cycle assessment (LCA).

In this chapter, published literature concerning the inclusion of the effect of the variation in surface albedo in LCA has been investigated. First, the state of the art about the evaluation of the variation of surface albedo on climate has been showcased. Then, an overview of the published studies about the evaluation of the variation of surface albedo in the built environment and, in particular, of building components has followed. Notwithstanding the findings are not comparable due to the heterogeneity of the studies, the case studies examined show the importance of including the evaluation of the variation in surface albedo in LCA studies. In particular, the inclusion of the effect of surface albedo in LCA studies related to building materials and components can provide an important source of information for decision makers in the field of urban sustainability.