Net-positive building carbon sequestration

A greater appreciation of architecture as a means to drive social, economic and environmental sustainability is emerging around the world. Practices are beginning to adopt closed-loop and cradle-to-cradle strategies, and some are even aiming toward net-positive design. However, life cycle assessment (LCA) tools do not measure ‘beyond zero’. The question of how net-positive carbon sequestration (i.e. impacts beyond net-zero) can be assessed within LCA is explored through a proposed carbon amortization performance (CAP) method. CAP overlays energy-related carbon and biomass sequestration over the building life cycle. CO2 equivalence (CO2e) is used to combine both positive and negative impacts from different sources. Net-positive contributions are defined as those exceeding ‘zero operational carbon’ –after the embodied carbon is paid back during the life cycle. The CAP method was tested on a building design withthe technical support of multidisciplinary experts. The results indicate that a building can sequester more carbon overits life cycle than it emits by using on-site current renewable energy technology and extensive building-integrated vegetation. Buildings designed on net-positive development principles can potentially reverse their carbon impact and begin to regenerate their regions, while providing multiple eco-services.