Measurement challenges for Ocean Alkalinity Enhancement (OAE)
It's hard to know when CO2 goes into the ocean from added alkalinity, and added Alkalinity disperses so quickly that measuring it is difficult
Details
Core information and root causes
Context
From our interview with Dr. Kimberly Gilbert of pHathom:
...as we increase CO2 in the atmosphere, that naturally pushes additional CO2 into the ocean. In fact, the ocean has helped mitigate climate change already by absorbing so much CO2. The downside for the ocean is when that happens, the CO2 becomes carbonic acid. It acidifies the ocean. That becomes corrosive to corals and lobsters and oysters and it kills other organisms. By adding a little bit of alkalinity (or a base) to the ocean, they can raise the pH a little bit, almost imperceptibly, but then that neutralizes some of that CO2 that's in the ocean and allows more to be drawn down into the ocean.
When I was working at Carbon to Sea Initiative I really loved the concept, but OAE has some inherent challenges. Primarily, it's really difficult to measure that - the ocean is really big. It doesn't matter how much alkalinity you add to the ocean when it disperses after a few minutes; it's an imperceptible measurement. And then when the actual CO2 goes into the ocean is anyone's guess, right? They're working on modeling techniques and measurement techniques, but it goes in when it goes in.
Efforts
Current initiatives and solutions
Groups working to address this bottleneck
Hourglass is a non-profit research organization that brings together interdisciplinary scientists to conduct targeted, integrated, and independent model, laboratory, and field work that rapidly de-risks the key uncertainties on how to safely and effectively scale mineral-based OAE techniques.
Funded by:
- Larsen Lam Climate Change Foundation
- Grantham Foundation
- Greenbridge Family Foundation
- National Oceanic and Atmospheric Administration (NOAA)
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Forecast
Future scenarios and predictions
Three potential futures for this bottleneck (MRV of Ocean Alkalinity Enhancement) based on current trends and plausible developments.
Scalable OAE Through Breakthrough Monitoring
🟡 Shifts
New advances in ocean sensors, tracer technologies, and satellite-based detection make it possible to measure and verify Ocean Alkalinity Enhancement (OAE) with sufficient confidence. While not perfect, the improved monitoring enables scaled pilots and limited credit generation.
WHAT CHANGES:
Ocean-based MRV (Monitoring, Reporting, and Verification) reaches "good enough" status. New sensors track alkalinity plumes, novel tracers identify CO2 fate, and advanced modeling tools increase confidence in ocean-carbon accounting over meaningful spatial and temporal scales.
WHY IT HAPPENS:
- Increased investment from philanthropic and public sectors (e.g., Hourglass, NOAA)
- Cross-pollination from oceanography, climate science, and synthetic biology
- Modeling breakthroughs using autonomous vehicles and machine learning
- Growing urgency to scale CDR beyond land-based options
WHAT IT MEANS:
The MRV bottleneck doesn't disappear but becomes manageable. Regulators and funders accept measurement uncertainty within acceptable thresholds, especially for pilot-scale and pre-compliance carbon markets. OAE scales cautiously but significantly.
WHEN:
- Early signs: 2025–2028
- Full effect: 2030–2035
LIKELIHOOD: MEDIUM
Sensor and tracer tech are rapidly improving, and small-scale deployments can provide validation. However, full spatial attribution in open ocean remains complex and costly.
Ocean CDR Standardization And Global Credit Systems
🟢 Disappears
A standardized framework for MRV of ocean-based carbon removal is adopted by global climate actors, enabling mainstream inclusion of OAE in voluntary and compliance carbon markets.
WHAT CHANGES:
Organizations like Verra, Gold Standard, and the UNFCCC adopt protocols for ocean carbon removal based on ensemble modeling, probabilistic MRV, and long-term observational baselines. Satellite and in-situ data feed into real-time verification dashboards.
WHY IT HAPPENS:
- Carbon markets demand diversified removal portfolios
- Scientific consensus forms around minimum viable MRV thresholds
- Multilateral coalitions (e.g., Ocean CDR Standards Task Force) define open frameworks
- Intergovernmental bodies invest in persistent ocean sensors and data sharing
WHAT IT MEANS:
The measurement bottleneck disappears. OAE becomes a recognized CDR pathway with clear accounting methodologies. Developers can pursue large-scale deployment with credible access to carbon credits and government incentives.
WHEN:
- Early signs: 2026–2029
- Full effect: 2032–2037
LIKELIHOOD: MEDIUM
Political and institutional alignment is tough, but the convergence of CDR urgency, philanthropic funding, and multilateral climate cooperation make this pathway plausible—especially if land-based options fall short.
Measurement Intractability Blocks OAE Scale
đź”´ Multiplies
Despite technical and modeling advances, MRV for ocean alkalinity enhancement remains scientifically and politically intractable. The inability to prove net CO2 removal or track fate limits deployment, funding, and credibility.
WHAT CHANGES:
Data gaps persist across spatial, temporal, and chemical domains. No consensus emerges on "how much is enough" for OAE MRV. Activist backlash and marine ecosystem uncertainties lead to regulatory caution and public opposition.
WHY IT HAPPENS:
- Ocean dynamics remain too chaotic for high-resolution attribution
- MRV costs remain prohibitively high for large-scale deployment
- Lack of real-world field data stalls standard-setting processes
- Environmental concerns slow permitting and drive negative media narratives
WHAT IT MEANS:
OAE is sidelined in favor of land-based or engineered CDR. Research continues, but deployments are limited to small-scale academic pilots. The bottleneck deepens as other CDR approaches attract clearer regulatory and financial pathways.
WHEN:
- Early signs: 2024–2027
- Full effect: 2030–2035
LIKELIHOOD: MEDIUM
This scenario is plausible without rapid, coordinated investment in field trials and sensor development. Political and ecological caution could amplify barriers despite scientific interest.
Cross Impact Analysis
- Sensor technology and tracer-based attribution are pivotal in all non-collapse futures
- Standardized MRV thresholds and political acceptance of probabilistic accounting are make-or-break leverage points
- Early indicators include global MRV working groups, open ocean field trials, and integration of OAE in pre-compliance markets
Bottleneck Resilience Evaluation
This bottleneck is technically fluid but politically brittle. Ocean MRV is advancing, but institutional and ecological uncertainties constrain its scale. With targeted investment and scientific consensus, it can shift or disappear—but without alignment, it risks becoming a dead-end for carbon removal.
Notes:
- “Disappears” = Scenario 2; “Shifts” = Scenario 1; “Multiplies” = Scenario 3.
- Cross-sector consortia (e.g., Hourglass Climate) are essential to building trust, standards, and data infrastructure.