Project SeaCURE: A New Frontier in Ocean-Based Carbon Capture

The ocean is one of Earth’s most effective natural carbon sinks, absorbing about 25% of CO₂ emissions from human activities. In a pioneering initiative on England’s south coast, a project named SeaCURE is exploring a way to enhance the ocean’s carbon absorption capacity.

This experimental project seeks to transform the ocean from a passive absorber into an active tool against climate change.

What is Project SeaCURE?

1. Location: Based in Weymouth, England.
2. Objective: Test whether extracting CO₂ from seawater can become a scalable, cost-effective method of reducing atmospheric carbon.
3. Unlike direct air capture or emissions-source capture, SeaCURE targets carbon already dissolved in seawater, which is up to 150 times more concentrated than in the air.

How the Technology Works

1. Step 1: Seawater is pumped from the English Channel into a treatment facility.
2. Step 2: The water is made more acidic, prompting dissolved carbon to convert into gaseous CO₂.
3. Step 3: The released CO₂ is captured before escaping into the atmosphere.
4. Step 4: CO₂ is then absorbed using sustainable sorbents, such as charred coconut husks.
5. Step 5: The treated water is neutralised and returned to the ocean to absorb more CO₂.

Current Impact

1. The pilot project currently removes only ~100 metric tonnes of CO₂ per year, equivalent to emissions from one transatlantic flight.
2. However, SeaCURE estimates that if just 1% of ocean surface water were treated using this method, it could remove up to 14 billion tonnes of CO₂ annually.
3. This figure is achievable only if powered by renewable sources, such as offshore floating solar panels.

 

Challenges and Environmental Concerns

1. The process requires substantial energy to create acidic and alkaline substances needed for carbon extraction.
2. If non-renewable energy is used, the environmental benefit may be significantly reduced.
3. Ecological risks include:
   1. Disrupting the natural carbon balance in marine ecosystems.
   2. Potential harm to marine organisms like phytoplankton (which need CO₂ for photosynthesis) and mussels (which need it to form shells).

Context: Ocean Acidification

1. Increased CO₂ absorption by oceans makes water more acidic, a phenomenon known as ocean acidification.
2. Though oceans are still slightly alkaline, even minor pH changes can affect corals, mussels, and shell-forming species.
3. SeaCURE highlights the importance of balancing carbon removal with ocean chemistry health.

Broader Relevance and Future Potential

1. SeaCURE is one of 15 early-stage projects testing new methods for carbon dioxide removal (CDR).
2. Climate experts stress that novel carbon capture approaches are essential to meet global net-zero targets.
3. If successful, ocean-based projects like SeaCURE could become a cornerstone in climate change mitigation strategies.

The ocean has always acted as a natural stabiliser of Earth’s climate. Projects like SeaCURE represent a paradigm shift, transforming a passive process into an active climate solution. While technical and ecological hurdles remain, the promise of scalable ocean carbon capture could mark a turning point in the fight against global warming.