High-resolution data-assimilative models are needed to support real-world testing of OAE. These modeling tools must:

• Account for complex interactions in the immediate vicinity of the alkalinity release and downstream impacts
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of OAE. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from OAE must include estimates of the “opportunity cost” of OAE - how did OAE shift phytoplankton community composition, production, and export? 

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from OAE, allowing for informed placement of sensors to monitor the field trials
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake)
• Inform a prioritized set of predictions to be tested during field trials

High-resolution data-assimilative models are needed to support real-world testing of OAE. These modeling tools must:

• Account for complex interactions in the immediate vicinity of the alkalinity release and downstream impacts
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of OAE. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from OAE must include estimates of the “opportunity cost” of OAE - how did OAE shift phytoplankton community composition, production, and export? 

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from OAE, allowing for informed placement of sensors to monitor the field trials
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake)
• Inform a prioritized set of predictions to be tested during field trials

High-resolution data-assimilative models are needed support real-world testing of OAE. These modeling tools must:

• Account for complex interactions in the immediate vicinity of the alkalinity release and downstream impacts
• Provide four-dimensional (space and time) estimates of biogeochemistry in zone of influence both in the presence and absence of OAE. The difference between these two simulations can be used to inform CDR estimates that account for background variability in the ocean. 
  • CDR estimates from OAE must include estimates of the “opportunity cost” of OAE - how did OAE shift phytoplankton community composition, production, and export? 

To support the design of proof-of-concept field trials, these models should also: 

• Provide estimates of the size and scale of biogeochemical modification to the ecosystem from OAE, allowing for informed placement of sensors to monitor the field trials
• Be capable of simulating passive tracers (e.g. SF₆) to inform whether and how these passive tracers may be useful in field trials (e.g., estimating rates of atmospheric CO₂ uptake)
• Inform a prioritized set of predictions to be tested during field trials

Standardized methodologies from third parties to verify uptake of atmospheric CO₂ resulting from ocean alkalinity enhancement will ultimately need to be developed to enable trading of carbon removal credits. Key first steps to support development of these protocols include: 

• Convening experts to review advances from modeling tools (Develop New Modeling Tools to Support Design and Evaluation) and controlled field trials (Accelerate Design and Permitting of Controlled Field Trials) to identify satisfied and outstanding data needs necessary to quantify additional CO₂ uptake as a direct result of OAE. As advances in OAE RD&D are made, the satisfied and outstanding data needs will need to be updated.
• Apply existing or develop when necessary, life cycle analysis tools to calculate stored carbon after accounting for emissions from required materials, energy, transportation/dispersal, etc.
• Include aspects of sustained monitoring to verify CDR permanence over long time scales as CDR is scaled.

Standardized methodologies from third parties to verify uptake of atmospheric CO₂ resulting from ocean alkalinity enhancement will ultimately need to be developed to enable trading of carbon removal credits. Key first steps to support development of these protocols include: 

• Convening experts to review advances from modeling tools (Develop New Modeling Tools to Support Design and Evaluation) and controlled field trials (Accelerate Design and Permitting of Controlled Field Trials) to identify satisfied and outstanding data needs necessary to quantify additional CO₂ uptake as a direct result of OAE. As advances in OAE RD&D are made, the satisfied and outstanding data needs will need to be updated.
• Apply existing^[1]Koornneed, J. and Nieuwlaar, E., 2009. Environmental life cycle assessment of CO₂ sequestration through enhanced weathering of olivine. Working paper, Group Science, Technology and Society, Utrecht University. ^[2]Hartmann, J., West, A.J., Renforth, P., Köhler, P., De La Rocha, C.L., Wolf‐Gladrow, D.A., Dürr, H.H. and Scheffran, J., 2013. Enhanced chemical weathering as a geoengineering strategy to reduce atmospheric carbon dioxide, supply nutrients, and mitigate ocean acidification. Reviews of Geophysics, 51(2), pp.113-149. or develop when necessary, life cycle analysis tools to calculate stored carbon after accounting for emissions from required materials, energy, transportation/dispersal, etc.
• Include aspects of sustained monitoring to verify CDR permanence over long time scales as CDR is scaled.

Standardized methodologies from third parties to verify uptake of atmospheric CO₂ resulting from ocean alkalinity enhancement will ultimately need to be developed to enable trading of carbon removal credits. Key first steps to support development of these protocols include: 

• Convening experts to review advances from modeling tools (Develop New Modeling Tools to Support Design and Evaluation) and controlled field trials (Accelerate Design and Permitting of Controlled Field Trials) to identify satisfied and outstanding data needs necessary to quantify additional CO₂ uptake as a direct result of OAE. As advances in OAE RD&D are made, the satisfied and outstanding data needs will need to be updated.
• Apply existing^[1]Koornneed, J. and Nieuwlaar, E., 2009. Environmental life cycle assessment of CO₂ sequestration through enhanced weathering of olivine. Working paper, Group Science, Technology and Society, Utrecht University. ^[2]Hartmann, J., West, A.J., Renforth, P., Köhler, P., De La Rocha, C.L., Wolf‐Gladrow, D.A., Dürr, H.H. and Scheffran, J., 2013. Enhanced chemical weathering as a geoengineering strategy to reduce atmospheric carbon dioxide, supply nutrients, and mitigate ocean acidification. Reviews of Geophysics, 51(2), pp.113-149. or develop when necessary, life cycle analysis tools to calculate stored carbon after accounting for emissions from required materials, energy, transportation/dispersal, etc.
• Include aspects of sustained monitoring to verify CDR permanence over long time scales as CDR is scaled.

Standardized methodologies from third parties to verify uptake of atmospheric CO₂ resulting from ocean alkalinity enhancement will ultimately need to be developed to enable trading of carbon removal credits. Key first steps to support development of these protocols include: 

• Convening experts to review advances from modeling tools (3a) and controlled field trials (3b) to identify satisfied and outstanding data needs necessary to quantify additional CO₂ uptake as a direct result of OAE. As advances in OAE RD&D are made, the satisfied and outstanding data needs will need to be updated.
• Apply existing^[1]Koornneed, J. and Nieuwlaar, E., 2009. Environmental life cycle assessment of CO₂ sequestration through enhanced weathering of olivine. Working paper, Group Science, Technology and Society, Utrecht University. ^[2]Hartmann, J., West, A.J., Renforth, P., Köhler, P., De La Rocha, C.L., Wolf‐Gladrow, D.A., Dürr, H.H. and Scheffran, J., 2013. Enhanced chemical weathering as a geoengineering strategy to reduce atmospheric carbon dioxide, supply nutrients, and mitigate ocean acidification. Reviews of Geophysics, 51(2), pp.113-149. or develop when necessary, life cycle analysis tools to calculate stored carbon after accounting for emissions from required materials, energy, transportation/dispersal, etc.
• Include aspects of sustained monitoring to verify CDR permanence over long time scales as CDR is scaled.

Standardized methodologies from third parties to verify uptake of atmospheric CO₂ resulting from ocean alkalinity enhancement will ultimately need to be developed to enable trading of carbon removal credits. Key first steps to support development of these protocols include: 

• Convening experts to review advances from modeling tools (3a) and controlled field trials (3b) to identify satisfied and outstanding data needs necessary to quantify additional CO₂ uptake as a direct result of OAE. As advances in OAE RD&D are made, the satisfied and outstanding data needs will need to be updated.
• Apply existing^,, or develop when necessary, life cycle analysis tools to calculate stored carbon after accounting for emissions from required materials, energy, transportation/dispersal, etc.
• Include aspects of sustained monitoring to verify CDR permanence over long time scales as CDR is scaled.

Research, development, and demonstration of OAE may be accelerated and strengthened by creating partnerships with key industries/sectors, including:  

• Transoceanic shipping – cargo vessels often travel at less than full capacity, provide onboard power, and move from port to port providing frequent opportunities to acquire new alkaline material and offload byproducts from alkalinization processes. Developing partnerships with the shipping industry to help the industry fulfill its commitments to decarbonize shipping could be a stepping stone to accelerate ocean-based net negative emissions (e.g. Poseidon Principles).
• Industries generating alkaline byproducts for feedstock into OAE processes (steel, aluminum, cement, lime, and nickel production; coal and biomass combustion).
  • 7 billion tons of alkaline byproducts generated annually from manufacturing and combustion could decrease costs and potentially facilitate transitions to larger-scale OAE. 
• Finfish and shellfish aquaculture, as well as coral reefs, where the added alkalinity could be used to optimize chemical conditions, including providing relief from ocean acidification. 
• Offshore renewable energy production, including wind and others, both as power sources and as integrated CDR platforms.
• Coastal industries, including desalination and wastewater treatment facilities, which already have infrastructure for pumping/processing seawater or wastewater for alkalinity addition.
• Marine research laboratories that already pump seawater and have expertise, technical equipment and infrastructure to support research and development.

Developing and strengthening relationships with partner industries may also help promote greater public support, as well as potentially offer faster routes to obtaining the necessary permitting.

Research, development, and demonstration of OAE may be accelerated and strengthened by creating partnerships with key industries/sectors, including:  

• Transoceanic shipping – cargo vessels often travel at less than full capacity, provide onboard power, and move from port to port providing frequent opportunities to acquire new alkaline material and offload byproducts from alkalinization processes. Developing partnerships with the shipping industry to help the industry fulfill its commitments to decarbonize shipping could be a stepping stone to accelerate ocean-based net negative emissions (e.g. Poseidon Principles^[1]“Poseidon Principles” https://www.poseidonprinciples.org/ ).
• Industries generating alkaline byproducts for feedstock into OAE processes (steel, aluminum, cement, lime, and nickel production; coal and biomass combustion)^[2]Renforth, P. The negative emission potential of alkaline materials. Nat Commun 10, 1401 (2019). https://doi.org/10.1038/s41467-019-09475-5 .
  • 7 billion tons of alkaline byproducts generated annually from manufacturing and combustion could decrease costs and potentially facilitate transitions to larger-scale OAE^[3]Renforth, P. The negative emission potential of alkaline materials. Nat Commun 10, 1401 (2019). https://doi.org/10.1038/s41467-019-09475-5 . 
• Finfish and shellfish aquaculture, as well as coral reefs, where the added alkalinity could be used to optimize chemical conditions, including providing relief from ocean acidification^[4]Gattuso J-P, Magnan AK, Bopp L, Cheung WWL, Duarte CM, Hinkel J, Mcleod E, Micheli F, Oschlies A, Williamson P, Billé R, Chalastani VI, Gates RD, Irisson J-O, Middelburg JJ, Pörtner H-O and Rau GH (2018) Ocean Solutions to Address Climate Change and Its Effects on Marine Ecosystems. Front. Mar. Sci. 5:337. doi: 10.3389/fmars.2018.00337 . 
• Offshore renewable energy production, including wind and others, both as power sources and as integrated CDR platforms.
• Coastal industries, including desalination and wastewater treatment facilities, which already have infrastructure for pumping/processing seawater or wastewater for alkalinity addition.
• Marine research laboratories that already pump seawater and have expertise, technical equipment and infrastructure to support research and development.

Developing and strengthening relationships with partner industries may also help promote greater public support, as well as potentially offer faster routes to obtaining the necessary permitting.

Research, development, and demonstration of OAE may be accelerated and strengthened by creating partnerships with key industries/sectors, including:  

• Transoceanic shipping – cargo vessels often travel at less than full capacity, provide onboard power, and move from port to port providing frequent opportunities to acquire new alkaline material and offload byproducts from alkalinization processes. Developing partnerships with the shipping industry to help the industry fulfill its commitments to decarbonize shipping could be a stepping stone to accelerate ocean-based net negative emissions (e.g. Poseidon Principles).
• Industries generating alkaline byproducts for feedstock into OAE processes (steel, aluminum, cement, lime, and nickel production; coal and biomass combustion).
  • 7 billion tons of alkaline byproducts generated annually from manufacturing and combustion could decrease costs and potentially facilitate transitions to larger-scale OAE. 
• Finfish and shellfish aquaculture, as well as coral reefs, where the added alkalinity could be used to optimize chemical conditions, including providing relief from ocean acidification. 
• Offshore renewable energy production, including wind and others, both as power sources and as integrated CDR platforms.
• Coastal industries, including desalination and wastewater treatment facilities, which already have infrastructure for pumping/processing seawater or wastewater for alkalinity addition.
• Marine research laboratories that already pump seawater and have expertise, technical equipment and infrastructure to support research and development.

Developing and strengthening relationships with partner industries may also help promote greater public support, as well as potentially offer faster routes to obtaining the necessary permitting.

First-Order Priorities to build public support for ocean-based CDR pathways are found in the Public Support road map Additionally, there are some specific opportunities to cultivate public engagement in and support around OAE including: 

• Developing targeted public outreach/advocacy campaigns to inform about OAE and its potentials with regards to ameliorating ocean acidification 
• Responding to the narrative of OAE as less “nature-based” than, for instance, coastal blue carbon restoration with the concept that OAE represents an acceleration of “natural” chemical weathering.

First-Order Priorities to build public support for ocean-based CDR pathways are found in the Public Support road map Additionally, there are some specific opportunities to cultivate public engagement in and support around OAE including: 

• Developing targeted public outreach/advocacy campaigns to inform about OAE and its potentials with regards to ameliorating ocean acidification 
• Responding to the narrative of OAE as less “nature-based” than, for instance, coastal blue carbon restoration with the concept that OAE represents an acceleration of “natural” chemical weathering.

First-Order Priorities to build public support for ocean-based CDR pathways are found in the Public Support road map Additionally, there are some specific opportunities to cultivate public engagement in and support around OAE including: 

• Developing targeted public outreach/advocacy campaigns to inform about OAE and its potentials with regards to ameliorating ocean acidification 
• Responding to the narrative of OAE as less “nature-based” than, for instance, coastal blue carbon restoration with the concept that OAE represents an acceleration of “natural” chemical weathering.

First-Order Priorities to build public support for ocean-based CDR pathways are found in the Public Support road map Additionally, there are some specific opportunities to cultivate public engagement in and support around OAE including: 

• Developing targeted public outreach/advocacy campaigns to inform about OAE and its potentials with regards to ameliorating ocean acidification 
• Responding to the narrative of OAE as less “nature-based” than, for instance, coastal blue carbon restoration with the concept that OAE represents an acceleration of “natural” chemical weathering.