RELEASING DIVALENT CATIONS TO SEQUESTER CARBON ON LAND AND SEA
Lead Research Organisation:
Heriot-Watt University
Department Name: Sch of Engineering and Physical Science
Abstract
The natural response of the carbon cycle to the warming induced by increased atmospheric CO2 features two negative feedbacks that remove CO2 from the atmosphere. One, caused by the greater acidity of the oceans, is for carbonate minerals to be dissolved, which causes an increase in the ability of seawater to contain carbon (as the bicarbonate ion). The other is for warmer conditions to increase the rate at which silicate minerals dissolve, with the products either precipitated as carbonate minerals, or flowing to the oceans. This silicate weathering also removes CO2 from the atmosphere.
Intentional acceleration of these two weathering feedbacks is a potential approach to remove the CO2 added to the atmosphere by burning of fossil fuels, and therefore alleviate extreme climate change. Such an approach is challenging, however, because to be useful at a significant scale (i.e. 1-10 GtC pa removal), requires a dramatic increase in weathering relative to natural rates. Whether such accelerated weathering is a feasible route to remove significant atmospheric CO2 is unknown. This proposal will address this unknown, and provide a comprehensive assessment of the feasibility of CO2 removal by accelerated weathering, including consideration of the technical, economic, environmental, and societal aspects of the approach.
The core of our work will be a life-cycle assessment of the enhanced-weathering approaches that might lead to 1-10Gt removal of CO2 per year. This modelling will start from the availability of minerals for weathering, paying particular but not exclusive attention to waste materials from industries such as mining. It will consider how the weathering of these minerals might be enhanced, either through treatment in mining waste piles or, in collaboration with project partners, by addition to soils. It will also consider the fate of the weathered materials, either as carbonate on land or in the sea, or as alkalinity in the sea. It will assess the economic cost of such approaches, the energy requirements, the environmental damage they would cause, and the societal limitations on such approaches (e.g. social acceptability, political, legal, governance).
In some key areas, understanding is not yet sufficient to allow this life-cycle assessment. We will address these gaps in knowledge by five specific pieces of research. These will:
1. Characterise how much waste material is available for enhanced weathering, including its location, its grain size, and its chemistry and mineralogy. This is critical information to underpin the life-cycle assessment.
2. Measure how quickly typical minerals weather and how this weathering rate changes with temperature and, particularly, through addition of microbes that are known to cause accelerated weathering of silicates.
3. Assess how best to scale up weathering to the 1-10GtC pa level. This will be done by both modelling of possible engineered approached to weathering, and by experiments on piles of silicate and carbonate minerals (each of 10 cubic meters), in which the conditions are altered and responses measured.
4. Assess the response of the ocean to increased alkalinity resulting from enhanced weathering. If more carbonate is produced in the ocean, it reduces the effectiveness of enhanced weathering; we will measure the rates of both inorganic and biological carbonate formation and their impact in the C cycle globally.
5. Consider how society will response to possible scenarios for accelerated weathering, and whether this may limit such an approach. Will enhanced weathering be socially acceptable? Will there be the political will to pursue it? Are their legal or governance barriers?
Information from these five "research components" will provide critical information for the life-cycle assessment, and thereby allow the overall potential and challenge of enhanced weathering CO2 removal to be fully assessed.
Intentional acceleration of these two weathering feedbacks is a potential approach to remove the CO2 added to the atmosphere by burning of fossil fuels, and therefore alleviate extreme climate change. Such an approach is challenging, however, because to be useful at a significant scale (i.e. 1-10 GtC pa removal), requires a dramatic increase in weathering relative to natural rates. Whether such accelerated weathering is a feasible route to remove significant atmospheric CO2 is unknown. This proposal will address this unknown, and provide a comprehensive assessment of the feasibility of CO2 removal by accelerated weathering, including consideration of the technical, economic, environmental, and societal aspects of the approach.
The core of our work will be a life-cycle assessment of the enhanced-weathering approaches that might lead to 1-10Gt removal of CO2 per year. This modelling will start from the availability of minerals for weathering, paying particular but not exclusive attention to waste materials from industries such as mining. It will consider how the weathering of these minerals might be enhanced, either through treatment in mining waste piles or, in collaboration with project partners, by addition to soils. It will also consider the fate of the weathered materials, either as carbonate on land or in the sea, or as alkalinity in the sea. It will assess the economic cost of such approaches, the energy requirements, the environmental damage they would cause, and the societal limitations on such approaches (e.g. social acceptability, political, legal, governance).
In some key areas, understanding is not yet sufficient to allow this life-cycle assessment. We will address these gaps in knowledge by five specific pieces of research. These will:
1. Characterise how much waste material is available for enhanced weathering, including its location, its grain size, and its chemistry and mineralogy. This is critical information to underpin the life-cycle assessment.
2. Measure how quickly typical minerals weather and how this weathering rate changes with temperature and, particularly, through addition of microbes that are known to cause accelerated weathering of silicates.
3. Assess how best to scale up weathering to the 1-10GtC pa level. This will be done by both modelling of possible engineered approached to weathering, and by experiments on piles of silicate and carbonate minerals (each of 10 cubic meters), in which the conditions are altered and responses measured.
4. Assess the response of the ocean to increased alkalinity resulting from enhanced weathering. If more carbonate is produced in the ocean, it reduces the effectiveness of enhanced weathering; we will measure the rates of both inorganic and biological carbonate formation and their impact in the C cycle globally.
5. Consider how society will response to possible scenarios for accelerated weathering, and whether this may limit such an approach. Will enhanced weathering be socially acceptable? Will there be the political will to pursue it? Are their legal or governance barriers?
Information from these five "research components" will provide critical information for the life-cycle assessment, and thereby allow the overall potential and challenge of enhanced weathering CO2 removal to be fully assessed.
Planned Impact
This project brings together a trans-disciplinary team to determine the efficacy of enhanced weathering and ocean alkalinity enhancement for greenhouse gas removal, as well as its technical and socio-economic feasibility, its wider governance, ethical and societal issues, and environmental impact. The project is expected to benefit a range of communities, in different ways and over different timescales:
1. Government policymakers: who are tasked to achieve the goal of keeping global temperatures to 1.5oC above preindustrial level. In support of this task, this project will provide a comprehensive assessment of the quantity of CO2 that could be removed due to enhanced weathering and ocean alkalinity enhancement, and over what timescale. The project will also provide predictions for CO2 uptake for a range of different technologies and technological approaches.
2. Industry, who are committed to reducing levels of greenhouse gas emissions and to developing techniques to manage atmospheric CO2. In this project we will work directly with the mining industry and provide a comprehensive assessment of how they could turn their 'waste' products into a commodity for CO2 reduction thereby reducing the carbon footprint of their activities. Managing levels of CO2 in this way will require industrial capabilities on a large scale that represents an opportunity to develop new income streams to the UK economy.
3. Intergovernmental Panel on Climate Change: Our research on the efficacy of enhanced weathering and ocean alkalinity enhancement is expected to feed in to the 6th IPCC Assessment Report which will have a strong focus on climate change mitigation strategies.
4. Civil Society: Global warming is a global issue that will significantly impact the lives of our children and grandchildren. Civil society is keenly interested in science that works to mitigate these impacts, but is rightly concerned that geoengineering approaches may have unintended consequences that do more harm than good. This project will undertake research to assess the potential costs and benefits of enhanced weathering and ocean alkalinity enhancement approaches. Communicating the results of this work, to both NGOs and the wider public, will be critical for driving this approach to full-scale deployment.
1. Government policymakers: who are tasked to achieve the goal of keeping global temperatures to 1.5oC above preindustrial level. In support of this task, this project will provide a comprehensive assessment of the quantity of CO2 that could be removed due to enhanced weathering and ocean alkalinity enhancement, and over what timescale. The project will also provide predictions for CO2 uptake for a range of different technologies and technological approaches.
2. Industry, who are committed to reducing levels of greenhouse gas emissions and to developing techniques to manage atmospheric CO2. In this project we will work directly with the mining industry and provide a comprehensive assessment of how they could turn their 'waste' products into a commodity for CO2 reduction thereby reducing the carbon footprint of their activities. Managing levels of CO2 in this way will require industrial capabilities on a large scale that represents an opportunity to develop new income streams to the UK economy.
3. Intergovernmental Panel on Climate Change: Our research on the efficacy of enhanced weathering and ocean alkalinity enhancement is expected to feed in to the 6th IPCC Assessment Report which will have a strong focus on climate change mitigation strategies.
4. Civil Society: Global warming is a global issue that will significantly impact the lives of our children and grandchildren. Civil society is keenly interested in science that works to mitigate these impacts, but is rightly concerned that geoengineering approaches may have unintended consequences that do more harm than good. This project will undertake research to assess the potential costs and benefits of enhanced weathering and ocean alkalinity enhancement approaches. Communicating the results of this work, to both NGOs and the wider public, will be critical for driving this approach to full-scale deployment.
Organisations
People |
ORCID iD |
Phil Renforth (Principal Investigator) |
Publications
Renforth P
(2020)
Editorial: The Role of Negative Emission Technologies in Addressing Our Climate Goals
in Frontiers in Climate
Renforth P
(2019)
Specialty Grand Challenge: Negative Emission Technologies
in Frontiers in Climate
Smith P
(2021)
Soil-derived Nature's Contributions to People and their contribution to the UN Sustainable Development Goals.
in Philosophical transactions of the Royal Society of London. Series B, Biological sciences
Smith P
(2019)
Land-Management Options for Greenhouse Gas Removal and Their Impacts on Ecosystem Services and the Sustainable Development Goals
in Annual Review of Environment and Resources
Xing L
(2022)
Potential of enhanced weathering of calcite in packed bubble columns with seawater for carbon dioxide removal
in Chemical Engineering Journal
Title | Creation of Animated Video - Ocean Alkalinity Enhacement |
Description | An animated video that describes ocean alkalinity enhancement to a climate aware audience |
Type Of Art | Film/Video/Animation |
Year Produced | 2020 |
Impact | Published in February 2020, video circulated but impact yet to be realised |
URL | https://www.youtube.com/watch?v=5obQ6aGSyHY |
Description | Our work on this project can be disaggregated into two key areas: 1) Significant new knowledge generated: We have developed the first comprehensive assessment of the global CO2 uptake potential of mine wastes (published in Bullock et al., 2021, doi: 10.3389/fclim.2021.694175), showing several GtCO2/yr may be possible. This suggest the potential of CO2 uptake in mine waste is similar in scale to other forms of carbon dioxide removal. Important new research questions opened up: how this potential may be most economically exploited should be the focus of further research. 2) Significant new knowledge generated: We have assessed the kinetics of carbonate dissolution in an elevated CO2 reactor, both through physical and modelling experiments (published in Xing et al., 2022, doi: 10.1016/j.cej.2021.134096). Such data may be used for the development of processes for removing CO2 from both concentrated sources, and lower concentration CO2 (e.g., created through direct air capture). |
Exploitation Route | 1) Mine waste carbon uptake potential may be used by mineral producers/mine operators to justify investment into carbon dioxide removal technologies in waste management facilities. 2) Carbonate weathering data can be used to constrain the engineering feasibility of the accelerated weathering of limestone |
Sectors | Construction Environment Manufacturing including Industrial Biotechology |
Description | Commercialisation of enhanced weathering has developed rapidly in 2022 with the formation of numerous companies that are attempting to exploit voluntary offset markets. Given that this organisations have raised $1 - 10s millions in their seed/Series A investment rounds suggests a collective market capitalisation on the order of $100 - 1000 million. Such an emerging industry would not have been possible without normalisation of enhanced weathering in carbon removal discourse, which has been an outcome of the GGREW project. |
First Year Of Impact | 2022 |
Sector | Environment,Other |
Impact Types | Economic |
Description | Contribution to EFI reports on GGR ("Unchartered Waters" + "Rock Solid") |
Geographic Reach | North America |
Policy Influence Type | Membership of a guideline committee |
Impact | Has impacted legislation in the US around GGR including the upcoming American Energy Innovation Act. This will result in a projected total of $727 million dedicated to GGR research, development, and demonstration activities for FY2022 - FY 2031. |
URL | https://energyfuturesinitiative.org/efi-reports |
Description | Greenhouse Gas Removal Technologies - approaches and implementation pathways in Scotland |
Geographic Reach | Local/Municipal/Regional |
Policy Influence Type | Implementation circular/rapid advice/letter to e.g. Ministry of Health |
URL | https://www.climatexchange.org.uk/media/3749/greenhouse-gas-removal-technologies.pdf |
Description | Greenhouse gas removal with UK agriculture via enhanced rock weathering |
Amount | £4,635,236 (GBP) |
Funding ID | BB/V011359/1 |
Organisation | Biotechnology and Biological Sciences Research Council (BBSRC) |
Sector | Public |
Country | United Kingdom |
Start | 04/2021 |
End | 11/2025 |
Description | Novel Materials for Increasing Ocean Alkalinity |
Amount | $400,000 (USD) |
Organisation | ClimateWorks |
Sector | Charity/Non Profit |
Country | United States |
Start | 03/2021 |
End | 03/2023 |
Description | Civil Service Environment Network |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Policymakers/politicians |
Results and Impact | A presentation to Civil Service Environment Network on carbon dioxide removal |
Year(s) Of Engagement Activity | 2021 |
Description | Frontiers in CDR |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Industry/Business |
Results and Impact | An information session on Frontier CDR - attended by over 200 people. |
Year(s) Of Engagement Activity | 2021 |
Description | Presentation - Engineering Geologists Special Interest Group |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Industry/Business |
Results and Impact | A recorded presentation to the Engineering Group of the Geological Society. Attending by ~50. Additional views online. General awareness raising to targeted industry. Follow up invitation to deliver training course at annual conference in March 2020 |
Year(s) Of Engagement Activity | 2019 |
URL | https://www.youtube.com/watch?v=_siZYhVGtIg&t=1s |
Description | Presentation to the Applied Group of the Mineralogical Society |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Presentation to the applied mineralogy group of the mineralogical society |
Year(s) Of Engagement Activity | 2020 |
Description | Round table British - German Cooperation to Study Climate Change and Adaptation Options |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Policymakers/politicians |
Results and Impact | The upcoming UN Climate Conference COP26 in November 2021 in Glasgow marks a critical moment in the long running effort to find global solutions to climate change. Science is and will be a crucial partner in this process. This motivated the British Embassy in Berlin and the Helmholtz Centre Potsdam GFZ to jointly organize a bilateral symposium to discuss appropriate research and adaptation strategies for climate change. |
Year(s) Of Engagement Activity | 2020 |
Description | Seminar Series on Carbon and Climate |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Postgraduate students |
Results and Impact | A seminar series given to Yale University A virtual lecture series hosted by the Departments of Earth and Planetary Sciences and Chemistry, the School of Engineering and Applied Science and the School of the Environment. |
Year(s) Of Engagement Activity | 2021 |
Description | Seminar at Harvard University |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Postgraduate students |
Results and Impact | Delivered a presentation to a seminar at Harvard University, specifically the implications of enhanced weathering for landscape architecture |
Year(s) Of Engagement Activity | 2020 |