Engineering soils to act as carbon sinks

PhD ThesisSoils containing calcium (Ca) and magnesium (Mg) bearing waste silicate minerals may be intentionally engineered to capture and store atmospheric carbon (C). Within the soil environment these minerals can capture and store atmospheric C through the process of weathering that releases Ca and Mg which then precipitate as carbonate minerals. Like natural silicates, silicate ‘wastes’ and artificial silicates sequester C through carbonation of calcium (Ca2+) and magnesium (Mg2+). Terrestrial CO2 sequestration may be promoted by the inclusion of these reactive mineral substrates in soils, and many waste sites and urban and anthropogenic soils already contain quantities of these materials. The UK Government is currently committed to reducing carbon emissions by 80% in 2050 (against a 1990 baseline) and soils have a role to play, acting as sinks for carbon. It is proposed that soil engineering measures could harness the high C turnover of the global pedologic system, ~120Pg C a-1 , to develop an efficient method of enhanced weathering. Artificial silicates have the potential to capture 192-333 Mt C a-1 , representing 2.0-3.7% of contemporary global C emissions; natural silicates present a carbon capture potential many orders of magnitude greater. Mineral carbonation in an artificial soil setting has the potential to capture inorganic carbon comparable to organic carbon accumulation. Soils of this type can accumulate 20-30 kg C m2 as carbonates (≥ organic carbon content in natural soils, ~17.5 kg C m2 for rural soils in the UK). Laboratory investigations were carried out on a number of experimental scales, from meso-scale flow-through reactors to micro-scale batch experiments, to determine the rate at which Ca and Mg could be supplied from suitable materials in engineered soil systems to perform a carbon capture function. Environmental factors were controlled for each in order to constrain their contribution to the overall process. Batch experiments were carried out at standard temperature and pressure (STP) to investigate effects of changes in solute concentration, water chemistry, agitation and particle size. pH controlled experiments were run at STP from pH 3-8, to determine the effects of pH changes on the weathering of wollastonite. Flow-through weathering experiments at STP investigated the effects of time, water chemistry, hydrogeological conditions and addition of CO2 on the weathering of steel slag. Analytical results demonstrate that Ca leaches rapidly from a number of Ca-rich artificial minerals providing great potential for carbon capture to occur on human-relevant timescales. Steel slag was shown to weather at a log rate of -9.39 to -11.88 mol Ca m-2 sec-1 in laboratory settings and -7.11 to - 7.56 mol Ca m-2 sec-1 under ambient environmental conditions in the field over 975 days. Anthropogenic soils, known to contain substantial quantities of Ca and Mg-rich minerals derived from industrial and demolition activity (including iron and steel slag, cement and concrete), were systematically sampled across two field sites. Analysis illustrated mean soil carbonate values of 21.8 ± 4.7% wt to 41.16 ± 9.89 wt % demonstrating that a large quantity of soil carbonate forms and persists in these environments, formed at a rate of 18kg CO2 t-1 a-1 . Stable isotope data ( 13C, 18O) confirm that up to 81% of C in these pedogenic carbonates is atmospherically derived. 14 C data also suggest that a significant proportion of the C present in carbonates analysed is ‘modern’. Applying a current CO2 trading cost of £8-£12 t-1 CO2, the potential value of CO2 sequestration at a study site was calculated to be £51,843 £77,765 ha-1 after 58% of its carbonation potential had been exploited. The studies contained in this thesis add to a growing body of evidence for the formation of carbonate minerals in soil settings where Ca/Mg-bearing silicate minerals occur. They also support the idea that engineered soils could be effectively utilised for carbon sequestration. Soil engineering for carbon capture provides a comparatively cheap, easy and attractive way of beginning to offset the environmental impact of certain industrial processes. Carbonation of waste silicates is a useful exercise in ‘closing the loop’ on C emissions produced in their manufacture. Carbon capture taking place on sites containing industrial waste materials is of interest to a variety of stakeholders: site owners, third sector bodies and local and national legislative bodies. Effective, low- energy field-scale implementation of mineral carbonation through soil engineering could assuage current constraints on economic performance of enhanced weathering technologies and highlight the importance of soil carbon storage.Natural Environment Research Counci

Trade-offs and synergies in the ecosystem service demand of urban brownfield stakeholders

Brownfield site redevelopment presents an opportunity to create urban green spaces that provide a wide range of ecosystem services. It is important, therefore, to understand which ecosystem services are demanded by stakeholders and whether there are trade-offs or synergies in this demand. We performed a quantitative survey of ecosystem service demand from brownfield sites that included all major stakeholder groups. Results showed that there was a strong trade-off between demand for services related to property development (e.g. ground strength and low flood risk) and all other services, which were linked to vegetated sites. There was a secondary, but weak, trade-off between demand for services of more ‘natural’ vegetated sites (e.g. with a biodiversity protection role) and those linked to aesthetics and recreation. Stakeholders with a strong preference for biodiversity protection formed a distinct group in their ecosystem service demands. While a ‘development’ vs ‘green space’ trade-off may be unavoidable, the general lack of strong trade-offs in demand for other services indicated that the creation of multifunctional greenspaces from former brownfield sites would be desirable to most stakeholders, as long as these are biophysically possible

Case studies on the effectiveness of capacity strengthening activities of the science granting councils initiative in Sub-Saharan Africa

The Science Granting Councils are at various stages in developing and implementing components of their science systems; for example, through deployment of learnings from the Science Granting Councils Initiative (SGCI) on public-private partnerships, and use of science, technology and innovation (STI) indicators in development and implementation of programmes. This report provides examples of how the SGCI has been effective and influential in context-dependent ways in the study countries. Findings suggest that all SGCs surveyed have been able to engage with, benefit from, and implement at least some of the trainings received by SGCI

Global social challenges for development studies in the Crisis in the Anthropocene

This panel discussion session explores some of the central dimensions of the Crisis in the Anthropocene that constitute global social challenges in the context of development studies. The conference theme highlighted the profound human impact on our blue-green-brown planet, that is already breaching planetary boundaries and pushing us beyond the roughly 1.5°C tipping point. This threatens liveability and sustainability in many localities and regions and may well rapidly be ‘off the scale’ of imaginability and survivability. Inevitably, as mounting empirical evidence and increasingly clear projections by the IPCC and other authoritative bodies show, these impacts are unevenly spread, both socially and spatially, both now and over the coming decades. The urgency of appropriate action is undeniable and we already know many dimensions of the required adaptations and transformations. Yet progress mostly remains too slow. These challenges are vital to the development studies community – heterogenous as it is – with our concerns for tackling poverty, inequality, deprivation and environmental degradation globally and locally. Hence this symposium asks what the crisis means for development theory, policy and practice and what development studies can and should be contributing to – and, indeed, whether it is capable of – addressing some key dimensions that warrant greater attention

Engaging at the science-policy interface as an early-career researcher: experiences and perceptions in biodiversity and ecosystem services research

Effective knowledge exchange at science-policy interfaces (SPIs) can foster evidence-informed policy-making through the integration of a wide range of knowledge inputs. This is especially crucial for conservation and sustainable use of biodiversity and ecosystem services (ES), human well-being and sustainable development. Early-career researchers (ECRs) can contribute significantly to knowledge exchange at SPIs. Recognizing that, several capacity building programs focused on sustainability have been introduced recently. However, little is known about the experiences and perceptions of ECRs in relation to SPIs. Our study focused on SPI engagement of ECRs who conduct research on biodiversity and ES, as perceived and experienced. Specifically, we addressed ‘motivations’, ‘barriers’ and ‘opportunities and ‘benefits’. A total of 145 ECRs have completed the survey. Our results showed that ECRs were generally interested to engage in SPIs and believed it to be beneficial in terms of contributing to societal change, understanding policy processes and career development. Respondents perceived lack of understanding about involvement channels, engagement opportunities, funding, training, perceived credibility of ECRs by other actors and encouragement of senior colleagues as barriers to engaging in SPIs. Those who have already participated in SPIs generally saw fewer barriers and more opportunities. A key reason for dissatisfaction with experience in SPIs was a lack of impact and uptake of science-policy outputs by policymakers–an issue that likely extends beyond ECRs and implies the need for transformations in knowledge exchange within SPIs. In conclusion, based on insights from our survey, we outline several opportunities for increased and better facilitation of ECR engagement in SPIs. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group

Head in the clouds, feet on the ground: how transdisciplinary learning can foster transformative change—insights from a summer school

There is a pressing need for transformative change, with a vision of long-term human well-being within planetary boundaries. The lack of progress—despite increasing awareness and action—illustrates how challenging it is to foster change in our complex global society. Education and learning are needed to enable change. Transdisciplinary learning, which meaningfully integrates diverse knowledge and perspectives, contributes to developing an integrative understanding—a necessity for tackling complex challenges. We explore how transdisciplinary learning for early-career researchers can foster transformative change and lead to increased biodiversity conservation. This paper focuses on a case study of the authors’ shared experiences during the 2021 Alternet Summer School, which focused on transformative change for biodiversity conservation and human well-being. In this introspective research, we gained insights through an online survey for participants and organizers of the summer school (n = 27). Using qualitative content analysis, we identify seven crucial elements of transdisciplinary learning which can lead to transformative change on (a) a personal level, as the learning process shifts values and helps researchers identify their roles; (b) a research level, by rethinking science and providing tools for transdisciplinary approaches, and (c) a societal level, by moving from the individual to the collective and constructing a shared vision for a sustainable future. Participants highlighted how changes on all these levels could benefit biodiversity conservation. These insights point to the benefit of transdisciplinary learning opportunities that empower young researchers to take up their part in fostering transformative change

Identifying future research directions for biodiversity, ecosystem services and sustainability: perspectives from early-career researchers

We aimed to identify priority research questions in the field of biodiversity, ecosystem services and sustainability (BESS), based on a workshop held during the NRG BESS Conference for Early Career Researchers on BESS, and to compare these to existing horizon scanning exercises. This work highlights the need for improved data availability through collaboration and knowledge exchange, which, in turn, can support the integrated valuation and sustainable management of ecosystems in response to global change. In addition, clear connectivity among different research themes in this field further emphasizes the need to consider a wider range of topics simultaneously to ensure the sustainable management of ecosystems for human wellbeing. In contrast to other horizon scanning exercises, our focus was more interdisciplinary and more concerned with the limits of sustainability and dynamic relationships between social and ecological systems. The identified questions could provide a framework for researchers, policy makers, funding agencies and the private sector to advance knowledge in biodiversity and ES research and to develop and implement policies to enable sustainable future development

A new valuation school : Integrating diverse values of nature in resource and land use decisions

We are increasingly confronted with severe social and economic impacts of environmental degradation all over the world. From a valuation perspective, environmental problems and conflicts originate from trade-offs between values. The urgency and importance to integrate nature's diverse values in decisions and actions stand out more than ever. Valuation, in its broad sense of 'assigning importance', is inherently part of most decisions on natural resource and land use. Scholars from different traditions -while moving from heuristic interdisciplinary debate to applied transdisciplinary science- now acknowledge the need for combining multiple disciplines and methods to represent the diverse set of values of nature. This growing group of scientists and practitioners share the ambition to explore how combinations of ecological, socio-cultural and economic valuation tools can support real-life resource and land use decision-making. The current sustainability challenges and the ineffectiveness of single-value approaches to offer relief demonstrate that continuing along a single path is no option. We advocate for the adherence of a plural valuation culture and its establishment as a common practice, by contesting and complementing ineffective and discriminatory single-value approaches. In policy and decision contexts with a willingness to improve sustainability, integrated valuation approaches can be blended in existing processes, whereas in contexts of power asymmetries or environmental conflicts, integrated valuation can promote the inclusion of diverse values through action research and support the struggle for social and environmental justice. The special issue and this editorial synthesis paper bring together lessons from pioneer case studies and research papers, synthesizing main challenges and setting out priorities for the years to come for the field of integrated valuation.Peer reviewe