Introduction
As the world grapples with the escalating impacts of climate change, innovative solutions to reduce atmospheric carbon dioxide (CO2) are gaining traction. One such groundbreaking initiative, the SeaCURE project, has begun operating on England’s south coast in Weymouth, aiming to extract carbon from seawater to combat global warming. Launched in April 2025, this pilot scheme, backed by £3 million in UK government funding, is testing a novel approach to carbon capture that could prove more efficient than traditional methods. By leveraging the ocean’s natural ability to store carbon, SeaCURE represents a bold step toward achieving net-zero emissions. This blog post explores the mechanics of the SeaCURE project, its potential to reshape carbon capture technology, the challenges it faces, and its broader implications for climate action, drawing on insights from recent reports and public sentiment.
How SeaCURE Works: A New Frontier in Carbon Capture
The SeaCURE project, led by researchers from Plymouth Marine Laboratory and the University of Exeter, is a pioneering effort to remove CO2 from seawater, where it exists in concentrations about 150 times higher than in the air. This higher concentration makes seawater an attractive medium for carbon capture compared to direct air capture (DAC) technologies, which struggle with the dilute nature of atmospheric CO2.
The process begins with a pipe that extends under Weymouth’s stony beach into the Atlantic, sucking up seawater and bringing it onshore. Once inside the facility, the seawater is treated with an acidic solution to lower its pH, encouraging dissolved carbon to convert into CO2 gas. This gas is then released in a stainless steel tank called the “seawater stripper,” where it is captured using charred coconut husks for concentration and storage. To ensure environmental safety, the processed seawater is neutralized with an alkali to restore its pH before being pumped back into the sea via a stream. Once returned, this low-carbon seawater absorbs more CO2 from the atmosphere, creating a cyclical process that contributes to greenhouse gas reduction.
Dr. Paul Halloran, who leads the SeaCURE project, emphasizes its potential: “Seawater has got loads of carbon in it compared to the air, about 150 times more.” However, he acknowledges the energy-intensive nature of the process, which poses a significant challenge for scaling up. The project’s submission to the UK government suggests that processing just 1% of the world’s surface seawater could remove 14 billion tonnes of CO2 annually, provided the operation is powered by renewable energy sources like solar panels on floating installations.
The Context: Why Carbon Capture Matters
The SeaCURE project is part of a broader push to address climate change, which scientists agree requires both drastic emissions reductions and active carbon removal to meet net-zero targets by 2050. The Intergovernmental Panel on Climate Change (IPCC) estimates that 100–1,000 billion tonnes of CO2 must be removed this century to limit warming to 1.5°C. While cutting emissions from fossil fuels remains the priority, technologies like carbon capture are increasingly seen as essential to offset unavoidable emissions and historical pollution.
Traditional carbon capture methods focus on capturing emissions at industrial sources or extracting CO2 directly from the air. However, DAC is expensive, costing hundreds of dollars per tonne of CO2 removed, and energy-intensive due to the low concentration of CO2 in the atmosphere (about 0.04%). In contrast, seawater’s high carbon content offers a potentially more efficient alternative, though it comes with its own set of challenges, such as high energy demands and environmental concerns.
The UK, a leader in carbon capture and storage (CCS), has committed £21.7 billion to develop CCS clusters in regions like Teesside and Merseyside, aiming to store carbon beneath the North Sea. SeaCURE is one of 15 pilot projects funded by the government to explore innovative carbon removal technologies, reflecting a national strategy to foster green technologies, create jobs, and drive economic growth. Energy Minister Kerry McCarthy has hailed SeaCURE as a vital step toward net zero, emphasizing its role in supporting skilled jobs.
Opportunities and Potential Impact
The SeaCURE project offers several promising opportunities for climate mitigation and technological innovation. Its primary advantage lies in its efficiency. By targeting carbon in seawater, the process requires less energy to capture the same amount of CO2 compared to DAC. If scaled up, SeaCURE’s technology could significantly contribute to global carbon removal efforts, potentially removing billions of tonnes of CO2 annually. This scalability is critical, as current DAC facilities, like Climeworks’ Orca project in Iceland, capture only 4,000 tonnes of CO2 per year—equivalent to the emissions of fewer than 800 cars.
Moreover, SeaCURE’s integration with renewable energy could make it a model for sustainable carbon capture. Floating installations powered by solar or wind energy could operate offshore, avoiding competition with land-based resources and tapping into the ocean’s vast potential as a carbon sink. The project also aligns with the UK’s ambition to lead in CCS, building on existing infrastructure like depleted North Sea oil and gas reservoirs for carbon storage.
Beyond climate benefits, SeaCURE could drive economic growth. The project supports skilled jobs in Weymouth and fosters collaboration between academia, industry, and government. If successful, it could attract further investment in marine-based carbon capture, positioning the UK as a hub for green innovation.
Challenges and Criticisms
Despite its promise, SeaCURE faces significant hurdles. The most pressing is its high energy requirement, which could undermine its cost-effectiveness unless powered by abundant renewable energy. Dr. Halloran notes that “the energy requirements to generate the products that we require to do this from seawater are huge.” Scaling the process to a global level would demand massive renewable energy infrastructure, a challenge that requires technological and financial innovation.
Environmental concerns also loom large. Critics worry about the impact of low-carbon seawater on marine ecosystems. Guy Hooper from Exeter University is researching how processed seawater affects marine creatures, but the long-term effects of large-scale carbon extraction remain uncertain. For example, altering seawater chemistry could affect marine life, particularly species sensitive to pH changes. A related trial in St Ives Bay, which proposed adding magnesium hydroxide to seawater, faced scrutiny from the Seal Research Trust, which warned of risks to marine organisms and seabed ecosystems.
Public sentiment, as reflected on platforms like X, is mixed. Some users have called SeaCURE “insane” or a “waste of £3M taxpayer money,” arguing that its net benefit is negligible and that large-scale implementation could harm marine life. Others see it as an innovative step toward addressing climate change, though skepticism about its scalability and environmental impact persists.
Finally, the cost of carbon capture remains a barrier. While SeaCURE aims to be more cost-effective than DAC, the technology is still in its infancy, and achieving costs below $100 per tonne—as some experts hope—will require significant advancements. Dr. Oliver Geden of the IPCC notes that the choice of carbon capture methods will ultimately depend on cost, highlighting the need for SeaCURE to prove its economic viability.
The Broader Implications
The SeaCURE project is more than a scientific experiment; it’s a test case for the future of carbon capture and the role of oceans in climate mitigation. Oceans already absorb a quarter of human-produced CO2, but their capacity is diminishing due to warming and acidification. Technologies like SeaCURE could enhance the ocean’s role as a carbon sink, but they must be carefully managed to avoid unintended consequences.
The project also underscores the importance of global collaboration. While the UK is pioneering marine-based carbon capture, similar efforts are underway elsewhere. For example, Equatic, a US-based startup, is building a large-scale facility in Singapore to remove 3,650 tonnes of CO2 annually from seawater while producing green hydrogen. These initiatives highlight the potential for a global network of carbon capture technologies, but they also face skepticism from scientists who question their scalability and environmental risks.
Moreover, SeaCURE raises ethical questions about technological interventions in natural systems. As carbon capture becomes a necessity, society must balance the benefits of CO2 removal with the risks to ecosystems and the potential for greenwashing by industries seeking to offset emissions without reducing them. Robust monitoring and verification frameworks, as emphasized by Oxford’s Cameron Hepburn, will be critical to ensuring the integrity of such projects.
Looking Ahead: The Path to Scale
For SeaCURE to realize its potential, several steps are needed. First, the pilot must demonstrate that it can capture carbon efficiently and safely at a reasonable cost. Ongoing research into its environmental impact will be crucial to gaining public and regulatory support. Second, investment in renewable energy infrastructure is essential to power large-scale operations. Floating solar or wind-powered installations could make offshore carbon capture feasible, but they require significant funding and innovation.
Third, SeaCURE must navigate public skepticism and environmental concerns. Transparent communication and community engagement, as seen in the project’s collaboration with local stakeholders in Weymouth, will be vital. Finally, the project should integrate with broader CCS efforts, such as the UK’s East Coast Cluster, to create a cohesive strategy for carbon removal and storage.
Conclusion
The SeaCURE project is a bold and innovative attempt to harness the ocean’s potential in the fight against climate change. By extracting carbon from seawater, it offers a promising alternative to traditional carbon capture methods, with the potential to remove billions of tonnes of CO2 if scaled up. However, its success hinges on overcoming significant energy, environmental, and economic challenges. As the world races to meet net-zero targets, projects like SeaCURE highlight the need for creative solutions, rigorous research, and global cooperation. Whether it becomes a cornerstone of climate mitigation or a cautionary tale, SeaCURE is a testament to humanity’s determination to confront the climate crisis head-on.
