Carbon Capture And Utilization: A NovelApproach To Climate Mitigation ThroughOcean Alkalinity Enhancement
Maryam Hanif Balkhi
April 30, 2025
As the global climate crisis accelerates, the need for innovative, scalable solutions has never been more urgent.
Among the many emerging strategies, Carbon Capture and Utilization (CCU) has gained significant attention for its potential to reduce greenhouse gas emissions while generating economic value.
Unlike Carbon Capture and Storage (CCS), which typically involves injecting carbon dioxide into underground reservoirs, CCU repurposes captured CO₂ into commercially useful products such as synthetic fuels, chemicals, and construction materials.
This dual functionality offers a compelling avenue to contribute toward net-zero emissions targets by 2050.
Despite its promise, current CCU technologies are hampered by several limitations, includinghigh operational costs, energy-intensive processes, and limited scalability. Furthermore, some applications—like enhanced oil recovery—do not ensure the permanent removal of carbon from the atmosphere, raising concerns about their long-term effectiveness.
To unlock the full potential of CCU, the technology must be integrated with broader ecological systems and climate strategies. One such promising integration is the use of CCU to produce alkaline materials that can be deployed to enhance ocean alkalinity, a process that both sequesters carbon and improves marine resilience.
The State of CCU Today Carbon Capture and Utilization technologies are designed to intercept CO₂ emissions from industrial sources or directly from the air, and convert them into materials or substances ofeconomic value. Methods of capture typically include post-combustion systems, which extract CO₂ from exhaust gases after fossil fuel combustion; pre-combustion systems, which remove CO₂ during the processing of fuels; and oxy-fuel combustion, which burns fuel in an oxygen-rich environment to simplify the capture process.
Once captured, CO₂ can be transformed in a variety of ways. It may be used to enhance oilrecovery, converted into building materials through mineralization, synthesized into chemicals such as methanol or urea, or biologically processed using algae and microorganisms to create fuels and bio-based products.
While these approaches are technically feasible and increasingly market-ready, many of them fall short when it comes to durability of carbon sequestration and energy efficiency.
A key critique of the current CCU landscape is its limited impact on atmospheric CO₂ concentrations.
In order to meaningfully contribute to climate mitigation, CCU must evolve to deliver not just value-added products, but also permanent and measurable reductions in atmospheric carbon. That evolution could lie in its synergy with natural carbon sinks—particularly the ocean.
CCU Meets Ocean Alkalinity EnhancementThe ocean is Earth’s largest carbon sink, absorbing approximately a quarter of the carbon dioxide emitted annually. However, the rapid rise in CO₂ emissions has exceeded the ocean’s natural buffering capacity, leading to acidification that threatens marine ecosystems.
Ocean Alkalinity Enhancement (OAE) is a relatively novel climate intervention that aims to reverse this trend by adding alkaline substances to seawater, increasing its pH and, in turn, its ability to absorb more CO₂ from the atmosphere.
In this integrated approach, captured CO₂ is first converted into alkaline materials such asmagnesium hydroxide or synthetic limestone.
These materials can be strategically deployed in coastal environments—either directly into seawater or as components of coastal infrastructure like seawalls and breakwaters. As they slowly dissolve, they increase the surrounding water’s alkalinity, which enhances its CO₂ uptake while simultaneously mitigating local ocean acidification.
This strategy becomes even more compelling when embedded within existing or new coastalinfrastructure. Coastal regions, home to more than 40 percent of the global population, faceincreasing risks from sea-level rise, erosion, and storm surges. Incorporating CCU-derivedalkaline materials into these protective structures not only strengthens climate adaptation but also creates a distributed, long-term carbon sink in the ocean.
The gradual dissolution of the materials allows for sustained CO₂ removal over time, providing a durable and resilient climate solution.
Why This Approach Stands Out The integration of CCU with ocean alkalinity enhancement offers a multi-dimensional solution that addresses both mitigation and adaptation. It not only removes carbon from the atmosphere but also fortifies coastal areas against climate-induced threats and supports marine ecosystems by reducing ocean acidification.
The ability to deploy this solution at scale, particularly in densely populated coastal regions, makes it a practical and impactful tool in the climate policy arsenal.
By converting carbon emissions into materials that improve environmental resilience, thisapproach aligns with circular economy principles. It treats carbon not as waste to be buried but as a resource to be reintegrated into ecological and economic systems. This framing not only enhances the sustainability of CCU but also opens new pathways for innovation and public support.
Moreover, the approach dovetails with broader sustainable development goals, from fosteringgreen job creation in coastal communities to preserving biodiversity in vulnerable marinehabitats. It reflects an evolution in thinking—from reactive mitigation to proactive systemsintegration—where technology and nature work hand in hand to combat climate change.
Feasibility and Emerging Potential Although OAE is still an emerging field, research and pilot programs are beginning to validate its potential.
A 2022 report by the U.S. National Academies of Sciences, Engineering, and Medicine identified OAE as a scalable and promising pathway for carbon dioxide removal,estimating its potential to sequester up to 10 gigatons of CO₂ annually under optimizedconditions.
Innovative companies such as CarbonCure and Blue Planet are already utilizing CCU-derivedminerals in concrete production, demonstrating that captured CO₂ can be transformed into commercially viable and climate-positive building materials.
These real-world applications provide a foundation for expanding the use of such materials in ocean-based systems.
The benefits of this integrated approach are compelling. Mineralized carbon offers permanent sequestration on geological timescales. Alkaline material production can be achieved with lower energy intensity than many direct air capture technologies. And the distributed nature of coastal deployment reduces the need for massive centralized infrastructure, offering more flexible andlocalized solutions.
Challenges and the Road AheadDespite its promise, this approach faces several technical, environmental, and regulatory hurdles. The ecological impacts of large-scale alkalinity alteration must be carefully studied to avoid unintended consequences. Strict monitoring and adaptive management will be essential to safeguard marine life.
Cost remains a barrier, particularly in the early stages of development. While integration withexisting coastal infrastructure can reduce expenses, investments in research, materialprocessing, and distribution will require public-private partnerships and access to climatefinance mechanisms such as carbon markets and green bonds. Equally important is the development of a robust legal and governance framework. Ocean-based interventions span international waters and complex ecosystems. Regulatory clarity and international cooperation will be critical to ensure these technologies are deployed responsiblyand equitably.
ConclusionThe convergence of CCU and Ocean Alkalinity Enhancement represents a powerful and timelyinnovation in the fight against climate change. By turning captured CO₂ into materials thatenhance the ocean’s natural carbon storage capacity, we can unlock a solution that removes carbon, strengthens infrastructure, and protects biodiversity.
To fully realize this potential, collaboration between scientists, industry leaders, policymakers, and coastal communities will be essential. Targeted pilot projects can demonstrate feasibility and inform best practices, while clear policy support can accelerate investment and scale-up.
As we seek comprehensive strategies to meet our climate goals, integrating technologicalinnovation with natural systems may prove to be one of the most impactful approaches yet.
FAQs