Sustainable Urban Carbon Capture: Engineering Soils for Climate Change (SUCCESS)

We have found that soils in cities are more effective sinks for carbon than agricultural soils. Urban soils typically carry a burden of fine-grained materials derived from often a long history of demolition. These materials include cement dust, which contains calcium silicate minerals, and also lime (calcium hydroxide). What we have found is that calcium derived from these minerals combines rapidly with carbonate in solution, which ultimately is derived from two sources - plants or rainwater. The rate at which this process occurs is extremely rapid, typically 100 T CO2 are removed from the atmosphere for each hectare of ground monthly; that's in a patch of ground the size of a football pitch. The amounts of carbon stored in urban soils as a consequence of this process are around 300 T C per hectare (compared with 175 T C per hectare in agricultural soils), and this is achieved rapidly after demolition (within very few years).

We want to make sure that construction activity takes advantage of these findings, to help compensate for the CO2 emissions that arise from burning fossil fuels, and to contribute to the UK's ambitious targets for reducing our emissions. The potential is there - if engineered soils are strategically and systematically designed to have a carbon capture function we believe that around 10% of the UK's 2011 CO2 emissions could be captured in this way, as part of normal construction activity. The costs involved are far less than energy and capital intensive CO2 scrubbing systems that are fixed to specific plant, such as a power station. What's more, the design involves a range of ecosystem services and involves broadening the concept of 'Carbon Capture Gardens', which we have found to be very acceptable among a wide range of stakeholders, as pleasant spaces are created that communities can enjoy and engage with.

The proposed research is intended to address some significant questions:
1) Can we reproduce the soil carbonation process artificially, so we can be sure of the carbon capture value?
2) How can we validate the process, so that claims of carbon sequestration can be trusted?
3) Is the process genuinely worth doing, in the context of UK and global CO2 emissions reduction targets?
4) What effect does the process have on soils, especially their strength and ability to drain rainwater, thus preventing flooding?
5) What effect does this approach have on plant and animal communities? Will the plants that we want grow in ground that has been treated to optimize carbon capture?
6) How does this process fit in with existing regulations that affect brownfield sites?
7) Under what circumstances is the process economically viable, given the geographical controls on availability of materials?
8) Can individuals use this approach in their own gardens?

During the project, we will work with a wide range of stakeholders, from industry, local authorities and environmental groups as well as academics. We will engage students in monitoring work as part of the dissemination process. All the work will be openly published in appropriate forms, and we expect to build a growing community network associated with the project.

This proposal originates in past and present EPSRC research, using Pathway to Impact funding to build a community of academics and non-academics with a serious interest in the research. It intends to lead to delivery of research into practice by pioneer stakeholders.

The principle Impact activities needing EPSRC support involve communication. We will hold 2 stakeholder meetings/year (one Newcastle, one London/Birmingham; including sandpit-style workshops). We will participate in meetings with the public and related events organized by Newcastle Science City. The RAs will work closely with stakeholders, spending time on stakeholder premises as part of the research. We will publish in professional as well as academic journals, and present at international/national conferences (each 6 places in total) and via regional professional groups. International impact will build on links associated with Newcastle University's Singapore campus and Brazil (Science without Borders). Our new interactive website will allow users to estimate carbon savings, as well as offering documentation.

SUCCESS depends on knowledge, building a knowledge base that will pass peer-review scrutiny, leading to genuine scientific advances in understanding the process of carbon capture in urban soils. We will use this knowledge to address questions based on 'how?' 'why?', etc. SUCCESS involves combining a set of existing techniques, novelty lying in their coupled adoption for the purpose of the project.

SUCCESS has a key role for society, addressing a problem of wide public concern. Outcomes can be applied at a range of scales, from individual gardens (with indirect impacts on health) through to national governments and the formulation of strategic policy. SUCCESS may enhance quality of life by improving visible ecosystem services while addressing the invisible problem of atmospheric CO2. It will inform policy, through the evidence base that it will create. The work can extend to international development, given the dominance of cities as homes for the population, and the need to maximize their sustainability.

SUCCESS has a clear role in economic terms. It may not lead to a patentable product, as the process is natural and the principle has been published. Instead, it sets out to deliver procedures that can be adopted by specific sectors for the purposes of adding value to their business, leading to a direct monetary return thus creating wealth. For example, mining companies might find new markets for calcium silicate products. Developers need to minimize carbon costs, and SUCCESS is expected to provide routes to achieving this business goal. Local authorities provide strategic direction for development, and SUCCESS will inform planning in appropriate ways. During the project, a watchful eye will be kept on opportunities to create new companies, to exploit niches that the work creates, and these might attract inward investment. International trade, in association with development, is expected to take the form of adoption of practice that we create through SUCCESS.

SUCCESS depends on people. The PI and Co-I are from different disciplines, and each is enriched academically by the collaboration. The recently appointed Co-I will benefit from the experience of the PI, appointed nearly 30 years ago, in the management of a research proposal of this type. Thus skills will be increased within established staff, as well as in the RA cohort. Three RAs will be appointed; from different disciplines their ability to address societal problems will be enhanced by working as a coherent team. At the start of their career, they will work closely with stakeholders providing part of a pipeline of manpower provision. That pipeline starts with undergraduate/MSc students, not funded by EPSRC, who will be offered projects that align with SUCCESS; this is an excellent route for motivating and recruiting individuals to work of this type.