Periodic Reporting for period 3 - OceanNETs (Ocean-based Negative Emission Technologies - analyzing the feasibility, risks, and cobenefits of ocean-based negative emission technologies for stabilizing the climate)
Reporting period: 2023-01-01 to 2025-06-30
Limiting climate change to the levels set out in the Paris Agreement will require not only rapid and drastic reductions in greenhouse gas emissions by the middle of this century, but also sustainable measures to remove carbon dioxide (CO2) from the atmosphere on a large scale. The utilization of ocean-based negative emission technologies (NETs) has been proposed as an integral part of a broader CO2 removal (CDR) solution.
But knowledge about the effectiveness, environmental safety, governance requirements, and costs of ocean-based NETs is subject to uncertainties, which has led to research efforts to investigate their potential, feasibility, and limitations.
With OceanNETs, a consortium was formed to deliver a rigorous, independent assessment of ocean-based NETs. This brought together experts in climate science, marine biogeochemistry, economics, law, governance, and social sciences from 14 institutions in Europe and Australia. Over five years, OceanNETs has addressed knowledge gaps related to specific ocean-based NETs that were identified as having either a high CDR potential, enhanced sustainability, or notable co-benefits.
By the end of the project, OceanNETs had produced the most comprehensive picture to date of the potential role of ocean-based NETs in climate strategies and future policy measures.
The results suggest that some ocean-based NETs could contribute to climate neutrality if implemented responsibly and with appropriate safety precautions, but all involve trade-offs.
But knowledge about the effectiveness, environmental safety, governance requirements, and costs of ocean-based NETs is subject to uncertainties, which has led to research efforts to investigate their potential, feasibility, and limitations.
With OceanNETs, a consortium was formed to deliver a rigorous, independent assessment of ocean-based NETs. This brought together experts in climate science, marine biogeochemistry, economics, law, governance, and social sciences from 14 institutions in Europe and Australia. Over five years, OceanNETs has addressed knowledge gaps related to specific ocean-based NETs that were identified as having either a high CDR potential, enhanced sustainability, or notable co-benefits.
By the end of the project, OceanNETs had produced the most comprehensive picture to date of the potential role of ocean-based NETs in climate strategies and future policy measures.
The results suggest that some ocean-based NETs could contribute to climate neutrality if implemented responsibly and with appropriate safety precautions, but all involve trade-offs.
OceanNETs produced 71 deliverables and published 65 scientific papers so far, including contributions to the Guide to Best Practices in Ocean Alkalinity Enhancement Research.
Findings from OceanNETs have been incorporated into the “Cross-sectoral perspectives” chapter of the Sixth Assessment Report of the IPCC.
OceanNETs outcomes were shared through policy events and outreach materials that engaged decision-makers and the wider public.
Four policy briefs were created, which:
i) recommend that decision-makers should adopt a broader perspective on governance and explain the need for an extended governance framework for marine CDR,
ii) explains why ocean alkalinity enhancement (OAE) is among the most promising ocean-based NETs, and provide detailed insights into realistic OAE deployment scenarios,
based on iii) ocean liming and iv) electrochemical brine splitting. In a final synthesis report the complex results of OceanNETs are summarised in an accessible format for researchers across different disciplines.
It documents key findings and refers to deliverables and OceanNETs publications that provide deeper insight into the underlying data, methods, and analyses.
During OceanNETs, approximately 12,000 people were surveyed to examine public perceptions of a portfolio of ocean-based NETs.
The surveys and deliberative workshops in several countries revealed low public awareness of ocean-based NETs, with acceptability depending on perceptions of naturalness, risk and governance transparency.
Governance and legal analyses have revealed a diversified and partially overlapping regulatory landscape.
With regard to ocean-based NETs, regulatory gaps have been identified and guiding principles for responsibly expanding governance frameworks have been proposed.
Economic and policy modelling explored cost trends and incentives, highlighting that deployments depend more on governance clarity than on cost alone.
For ocean-based NET options to become feasible, policymakers should create incentives for near-term deployment of ocean-based NETs while establishing a rigorous basis for robust assessments of the associated economic costs.
Two novel experimental mesocosm studies were conducted to investigate impacts of OAE on the marine ecosystem and chemistry, yielding unique measurement data.
These data revealed potential benefits and possible ecological risks.
The observed effects on the ecosystem were minor, suggesting that OAE could be designed to minimize adverse effects.
The experimental data will likely be further exploited for cross-comparisons or syntheses with results from other related experimental studies in the future.
A key exploitable OceanNETs result is the provision of realistic future scenarios derived from in-depth case studies, for which life cycle assessments, economic growth and energy projections, and stakeholder information have been combined.
Two case studies examined “ocean liming” and “electrochemical salt splitting” in particular detail.
These case scenarios are an exclusive outcome that have been integrated into the project's model studies, but can also be leveraged and implemented in future analyses.
Computer simulations using regional high-resolution models and Earth system models provided valuable results of the CDR potential, mainly of OAE but also for combinations of ocean-based and land-based NETs.
The case scenarios of ocean liming were used for a joint multi-model ensemble analysis.
Simulation results show how CDR efficiency of OAE can vary in time and space, and that it is sensitive to CO2 emission pathways.
Specific model analyses addressed impacts of OAE on the marine ecosystem, documenting potentially small but significant changes in plankton composition and temporal delays in the development of algal blooms.
Findings from OceanNETs have been incorporated into the “Cross-sectoral perspectives” chapter of the Sixth Assessment Report of the IPCC.
OceanNETs outcomes were shared through policy events and outreach materials that engaged decision-makers and the wider public.
Four policy briefs were created, which:
i) recommend that decision-makers should adopt a broader perspective on governance and explain the need for an extended governance framework for marine CDR,
ii) explains why ocean alkalinity enhancement (OAE) is among the most promising ocean-based NETs, and provide detailed insights into realistic OAE deployment scenarios,
based on iii) ocean liming and iv) electrochemical brine splitting. In a final synthesis report the complex results of OceanNETs are summarised in an accessible format for researchers across different disciplines.
It documents key findings and refers to deliverables and OceanNETs publications that provide deeper insight into the underlying data, methods, and analyses.
During OceanNETs, approximately 12,000 people were surveyed to examine public perceptions of a portfolio of ocean-based NETs.
The surveys and deliberative workshops in several countries revealed low public awareness of ocean-based NETs, with acceptability depending on perceptions of naturalness, risk and governance transparency.
Governance and legal analyses have revealed a diversified and partially overlapping regulatory landscape.
With regard to ocean-based NETs, regulatory gaps have been identified and guiding principles for responsibly expanding governance frameworks have been proposed.
Economic and policy modelling explored cost trends and incentives, highlighting that deployments depend more on governance clarity than on cost alone.
For ocean-based NET options to become feasible, policymakers should create incentives for near-term deployment of ocean-based NETs while establishing a rigorous basis for robust assessments of the associated economic costs.
Two novel experimental mesocosm studies were conducted to investigate impacts of OAE on the marine ecosystem and chemistry, yielding unique measurement data.
These data revealed potential benefits and possible ecological risks.
The observed effects on the ecosystem were minor, suggesting that OAE could be designed to minimize adverse effects.
The experimental data will likely be further exploited for cross-comparisons or syntheses with results from other related experimental studies in the future.
A key exploitable OceanNETs result is the provision of realistic future scenarios derived from in-depth case studies, for which life cycle assessments, economic growth and energy projections, and stakeholder information have been combined.
Two case studies examined “ocean liming” and “electrochemical salt splitting” in particular detail.
These case scenarios are an exclusive outcome that have been integrated into the project's model studies, but can also be leveraged and implemented in future analyses.
Computer simulations using regional high-resolution models and Earth system models provided valuable results of the CDR potential, mainly of OAE but also for combinations of ocean-based and land-based NETs.
The case scenarios of ocean liming were used for a joint multi-model ensemble analysis.
Simulation results show how CDR efficiency of OAE can vary in time and space, and that it is sensitive to CO2 emission pathways.
Specific model analyses addressed impacts of OAE on the marine ecosystem, documenting potentially small but significant changes in plankton composition and temporal delays in the development of algal blooms.
OceanNETs delivered the first integrated, transdisciplinary assessment of ocean-based NETs, linking environmental science, marine biogeochemistry, economics, law, governance and public perception.
These results have contributed to a better understanding of possible strategies for achieving the climate goals set out in the Paris Agreement.
- OceanNETs findings shed light on how ocean-based NETs influence specific United Nations’ Sustainable Development Goals SDG 13 (climate action) and SDG 14 (life below water). The OceanNETs case study scenarios are linked to aspects of SDG 9 (innovation, industry and infrastructure). The experimental studies covered elements of SDG 14 as well as impacts on fish development that are relevant to SDG 2 (food security through fisheries).
- OceanNETs provided credible assessments of the scalability of ocean-based NETs that include information about their social and techno-economic constraints.
- OceanNETs contributed to a roadmap for planning and defining the scope of future research work, which should serve to address remaining challenges for the needed near-term deployment of ocean-based NETs.
- OceanNETS informed about forward-looking climate policies and explained the urgency of creating incentives for the timely implementation of ONETs.
- OceanNETs disclosed major ethical challenges when clear trade-offs between local and global interests must be achieved, suggesting expansions towards multi-level frameworks that facilitate the alignment of local efforts with international regulations for ocean-based NETs.
- OceanNET documented OAE and the cultivation and harvesting of macroalgae as two ocean-based NET options that could benefit from existing infrastructure, facilitating cost-effective implementation within a short timeframe.
- OceanNETs results of the life cycle assessments not only provided feasible OAE options, but also revealed meaningful additional valorization pathways of ocean liming, for which the CO2 emissions during the calcination process could be minimized through the use of low-carbon technologies and the integration of CO2 capture and storage.
These results have contributed to a better understanding of possible strategies for achieving the climate goals set out in the Paris Agreement.
- OceanNETs findings shed light on how ocean-based NETs influence specific United Nations’ Sustainable Development Goals SDG 13 (climate action) and SDG 14 (life below water). The OceanNETs case study scenarios are linked to aspects of SDG 9 (innovation, industry and infrastructure). The experimental studies covered elements of SDG 14 as well as impacts on fish development that are relevant to SDG 2 (food security through fisheries).
- OceanNETs provided credible assessments of the scalability of ocean-based NETs that include information about their social and techno-economic constraints.
- OceanNETs contributed to a roadmap for planning and defining the scope of future research work, which should serve to address remaining challenges for the needed near-term deployment of ocean-based NETs.
- OceanNETS informed about forward-looking climate policies and explained the urgency of creating incentives for the timely implementation of ONETs.
- OceanNETs disclosed major ethical challenges when clear trade-offs between local and global interests must be achieved, suggesting expansions towards multi-level frameworks that facilitate the alignment of local efforts with international regulations for ocean-based NETs.
- OceanNET documented OAE and the cultivation and harvesting of macroalgae as two ocean-based NET options that could benefit from existing infrastructure, facilitating cost-effective implementation within a short timeframe.
- OceanNETs results of the life cycle assessments not only provided feasible OAE options, but also revealed meaningful additional valorization pathways of ocean liming, for which the CO2 emissions during the calcination process could be minimized through the use of low-carbon technologies and the integration of CO2 capture and storage.