Engineering the soil carbon sink: a novel approach to carbon emission abatement

Lead Research Organisation: Newcastle University
Department Name: Civil Engineering and Geosciences

Abstract

Soils are the greatest land-based reservoir for carbon on the planet, containing three times as much carbon as do plants. Soil-atmosphere interactions exchange a third more CO2 with the atmosphere than do interactions between the atmosphere and the ocean. Soil thus plays a very significant role in controlling atmospheric CO2 levels.In this context, we have an opportunity to engineer soil systems so that the amount of CO2 that they take up is maximised. This a form of carbon abatement that is very cheap, because it is passive (there are no energy inputs once constructed). It is directly analogous to the use of constructed wetlands for the treatment of polluted waters. Our aim is to assess the feasibility of this process for widespread application in the UK, and to assess the associated costs and benefits.We will investigate the soil carbon contents of artificial soils from a number of sources. We will use trial plots constructed for a completely different purpose in 2002 and which we have recently shown to accumulate soil carbonates (the first such found in the UK). We will grow brassicas, as a representative bioenergy crop, in artificial soils in the lab and greenhouse, using calcium-rich wastes as part of the soil. We will sample brownfield and other remediated sites of known age and history. In all cases we will determine the carbon content of the soil in terms of different C reservoirs, and fingerprint each one using stable isotopes so that we can trace its plant origin.Using the information from the samples, we will be able to determine the lifetime of the different soil carbon reservoirs. We will be able to estimate how quickly they build up, if they are stable, and if they transform from one into another. Using this information we can model the behaviour of carbon in artificially planted systems.In the context of UK land use and the arisings of calcium-rich materials that could be used to accelerate the process, we will assess the possible benefits of designing soil systems to act as sites for the passive sequestration of atmospheric CO2. If the process appears to be feasible, we will use contacts initially in NE England to exploit our findings, through Newcastle's Science City which links us to industry, and through the University's CREEL project, funded by One North East and intended to act as an outreach facility for renewable energy.

Publications

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D Manning (2009) Growth of the soil

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Renforth P (2011) Silicate production and availability for mineral carbonation. in Environmental science & technology

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Renforth P (2011) Designing a carbon capture function into urban soils in Proceedings of the Institution of Civil Engineers - Urban Design and Planning

 
Description Using EPSRC Pathway to Impact funds, we have extended the application of the research to a range of stakeholders. Specifically we have developed the concept of 'Carbon Capture Gardens', a design for urban soils that enables local authorities and private landowners to recognise and realise a carbon capture function in a landscape or garden. This is proving very popular with the public - it is an easy way for individuals to feel they can play their part in mitigating climate change, and we have shown that 1 hectare removes 100 tonnes of CO2 from the atmosphere every month. More information is available from: http://research.ncl.ac.uk/engscc We have now built up a community of developers, engineers, consultants and regulators with whom we have periodic dialogue. This has led directly to our use of the 10 ha Science Central site in Newcastle for research purposes, and we now have a growing portfolio of other sites that we are using. The research also led into the design and now execution of much greater EPSRC funding, EPSRC SUE3 EP/I002154/1 SECURE: SElf Conserving URban Environments. Importantly, this work has broadened to enable us to engage with ecosystems service experts, and so other scientists are benefiting from our engagement. More widely, we have used Pathway to Impact funding to engage with this involved in the Soil Directive in Brussels, and this has led to ongoing communication, bearing in mind the considerable political difficulties that surround the Soil Directive. Additionally, the work has led to 4 Nuffield vacation studentships, giving 4 six formers chance to engage with our research. One of these is co-author on a paper in Environmental Science & Technology (Renforth, P., Washbourne, C.-L., Taylder, J., Manning, D.A.C. (2011) Silicate production and availability for mineral carbonation, Environmental Science and Technology, 45, 2035-2041). This is a remarkable achievement for a sixth-former (now studying Maths at Cambridge). Every month, urban soils can remove 100 tonnes of CO2 from the atmosphere per hectare. This function can be designed into 'carbon capture gardens' and other landscaping features as part of a redevelopment activity. We have built up a network of developers and other interested parties who are considering adopting our findings in their designs, as and when appropriate. Beneficiaries: Developers, engineering consultancies, regulators, general public Contribution Method: The research demonstrated how much CO2 is captured, and how quickly the process takes place. It has also addressed issues relating to site prioritisation in the context of other constraints, such as land contamination. It has pulled together regulatory, scientific, engineering and commercial constraints, to give all involved a wider understanding of a complex phenomenon. The project has led to 4 Nuffield Foundation Science Bursaries, one undergraduate project, 5 MSc projects and 2 PhD student projects. Beneficiaries: Students, industrial partners, and students' eventual employers Contribution Method: Creating project topics suitable for investigation at a range of levels and scales, with external stakeholder partnership where possible.
Sector Communities and Social Services/Policy,Construction,Education,Environment,Transport
Impact Types Cultural,Societal