Dynamic Accounting of Carbon Uptake in the Built Environment

Area of Science:

• Building science
• Environmental science
• Materials science

Background:

• Conventional life-cycle assessments (LCAs) of building materials often overlook dynamic CO2e fluxes and timing effects.
• Focusing solely on cradle-to-gate emissions can misrepresent the net climate impact of materials.
• Decarbonizing the industrial sector requires transforming materials from emitters to carbon sinks.

Purpose of the Study:

• To present a novel framework for analyzing the cradle-to-grave CO2e balance of building materials.
• To incorporate time-dependent global warming potential calculations for dynamic CO2e accounting.
• To evaluate the climate impact of materials considering the timing of emissions and carbon uptake.

Main Methods:

• Development of a framework for time-dependent CO2e balance analysis.
• Application of the framework within the Dynamic Accounting of Carbon Uptake in the Built Environment (D-CUBE) tool.
• Case studies analyzing concrete and cross-laminated timber (CLT) using the D-CUBE tool.

Main Results:

• Dynamic accounting reveals that long-term biogenic carbon storage in CLT significantly reduces its warming impact.
• The slow carbonation of concrete does not yield substantial global warming reductions when dynamic effects are considered.
• The D-CUBE tool enables consistent comparisons across materials and life-cycle stages.

Conclusions:

• A time-dependent CO2e analysis is essential for accurately assessing the climate impact of building materials.
• The D-CUBE tool provides a flexible platform for identifying emission hotspots and pathways to net-carbon-sequestering materials.
• Transforming building materials into carbon sinks necessitates accounting for the dynamic nature of carbon fluxes over their lifespans.