Developing lifecycle inventory indices for estimating the carbon sequestration of artificially engineered soils and plants

Recent research into soil engineering indicates that increased carbon sequestration through the conversion of atmospheric CO2 to a pedogenic carbonate mineral (calcite, CaCO3) may help mitigate global warming through artificially engineering a variety of soils with selected materials and vegetation so that they have a photosynthesis-driven carbon capture function. Non-biological processes of carbonation also occur, at high pH. In both cases, CO2 partitions into soil porewaters as dissolved carbonate, and precipitates by combining with Ca derived from portlandite (Ca(OH)2) and weathered cement-derived calcium silicates, derived from materials generated by the demolition process. This paper aims to illustrate a method for capturing lifecycle data by quantifying the stocks and flows of the process through a series of possible experiments which if proved successful will allow a deeper understanding of the
ability of soil calcite to act as a stable CO2 sink. The challenge is to identify noncalcined (i.e. calcium silicate) rocks, that weather sufficiently rapidly to provide a net sink for CO2, taking into account all emissions during production. The results will lead to normalised impact assessment data which can be applied globally within the fields of soil science and civil engineering. Furthermore, if the results indicate a strong uptake in terms of CO2 sequestration there is the potential to assist the United Kingdom’s 80% CO2 reduction target by 2050 through widespread adoption of the technology, provided that there is a positive cost-benefit ratio.