A pioneering new facility in Weymouth, Dorset, is taking an innovative approach to tackling climate change by extracting carbon dioxide directly from seawater.
Why?
While most climate efforts focus on cutting emissions or capturing carbon from the air, the SeaCURE project, developed by scientists from Plymouth Marine Laboratory (PML) and the University of Exeter, is tapping into the ocean’s natural role as a carbon sink.
Currently, the ocean absorbs around 25 per cent of the carbon dioxide (CO₂) humans release each year. However, as atmospheric CO₂ levels rise, so too does the concentration of dissolved carbon in seawater, thereby contributing to ocean acidification and threatening marine ecosystems.
SeaCURE’s new project aims to boost the ocean’s capacity to absorb even more CO₂, while simultaneously helping to remove some of the excess greenhouse gases already contributing to global warming.
What Is SeaCURE And Who Is Behind It?
SeaCURE is a collaborative project led by the University of Exeter’s Global Systems Institute, with key partners Plymouth Marine Laboratory, Brunel University London, and industrial water treatment specialist Eliquo Hydrok.
Backed by a £3 million grant from the UK Government’s Department for Business, Energy & Industrial Strategy (BEIS), SeaCURE is part of the Net Zero Innovation Portfolio’s Direct Air Capture & Greenhouse Gas Removals Innovation Programme. It is one of 15 pilot projects across the UK tasked with developing cutting-edge climate solutions.
How Does SeaCURE Actually Work?
The SeaCURE plant, discreetly tucked behind Weymouth’s SEA LIFE Centre, operates a relatively simple yet ingenious process:
– Seawater is pumped ashore from the English Channel via an existing intake pipe.
– Part of the water is treated to become more acidic. This triggers the dissolved CO₂ to form bubbles of gaseous carbon dioxide, much like opening a fizzy drink.
– The CO₂ gas is “stripped” out using a stainless steel tank system designed to maximise contact between the acidified water and the air.
– The captured gas is then drawn off and stored using activated carbon derived from coconut husks.
– The treated seawater is neutralised by adding an alkali solution before it is returned safely to the ocean.
Professor Tom Bell of Plymouth Marine Laboratory likens the CO₂ extraction process to “pouring a fizzy drink over a large surface,” allowing the carbon to escape quickly and be captured.
Why Target Seawater Instead Of Air?
While direct air capture of carbon has been a growing focus in climate tech circles, seawater offers some compelling advantages. For example, seawater actually contains about 150 times more CO₂ than the air. This means that, as Dr Paul Halloran, leader of the SeaCURE project says, it’s “potentially much more efficient to work with.”
Challenges
It’s worth noting here that extracting CO₂ from seawater in this way is certainly not without its challenges. For example, the energy requirements to acidify and neutralise seawater on a large scale are significant, meaning that scaling up would need to be paired with renewable energy sources, such as floating solar installations at sea.
The Scale Of The Pilot
As it currently stands, the SeaCURE pilot plant can remove up to 100 tonnes of CO₂ annually, which is less than the emissions from a single transatlantic flight! However, the potential is enormous.
For example, according to SeaCURE’s initial projections, processing just 1 per cent of the world’s surface seawater could, in theory, remove 14 billion tonnes of CO₂ each year! For comparison, global annual CO₂ emissions currently sit around 37 billion tonnes.
As Dr Oliver Geden, a carbon capture expert at the Intergovernmental Panel on Climate Change, notes that while “capturing directly from seawater is one of many options,” the ultimate choice will depend heavily on cost and scalability.
What About Marine Life?
Altering the chemistry of seawater raises understandable concerns about marine ecosystems. Early results from a parallel research strand led by Guy Hooper, PhD researcher with PML and the University of Exeter, suggest caution.
Hooper has been conducting laboratory experiments exposing marine organisms, such as phytoplankton and molluscs, to “low-carbon” water produced by the SeaCURE process.
“Marine organisms rely on carbon to perform essential processes,” Hooper explains. “Phytoplankton need it for photosynthesis, and creatures like mussels use it to build their shells.”
Initial findings indicate that large-scale release of low-carbon water could have some impact on marine life, although techniques such as pre-diluting the water before discharge could help mitigate risks.
“It’s vital we consider these impacts now, at the pilot stage, rather than later,” Hooper adds.
Early Days, But Big Implications
The SeaCURE project represents a significant step forward in exploring ocean-based carbon dioxide removal (CDR), an area that has received far less attention than land-based efforts.
Energy minister Kerry McCarthy has praised the project’s promise, stating: “Innovative projects like SeaCURE play an important role in creating the green technologies needed to reach net zero, while also supporting skilled jobs and economic growth.”
Although SeaCURE is still small-scale, its success could pave the way for a new generation of climate solutions that work with the ocean rather than against it. Should SeaCURE and similar projects prove viable at scale, they could complement broader efforts to curb emissions and offset unavoidable carbon outputs.
What Does This Mean For Your Organisation?
The SeaCURE project is in its infancy, but it still offers a glimpse into how innovation, science, and environmental stewardship could come together to tackle one of the greatest challenges of our time. By focusing on seawater, rather than solely the atmosphere, the researchers have opened up a new frontier in carbon removal that could eventually be scaled to global significance. That said, it’s clear that scaling something like this up will not be straightforward. The energy demands, potential ecological impacts, and cost considerations will all need to be carefully managed if SeaCURE and projects like it are to realise their full promise.
For UK businesses, particularly those operating in the green technology, energy, and marine sectors, SeaCURE’s early success could signal exciting new opportunities. Companies involved in renewable energy, carbon capture, and environmental monitoring, for example, may find themselves at the forefront of supporting or supplying future large-scale rollouts of this technology. Meanwhile, industries with significant carbon footprints could, in time, benefit from having new, credible carbon offset options grounded in science-backed marine solutions.
However, the implications extend far beyond business. Policymakers, environmental groups, and the wider public will all have a stake in how ocean-based carbon removal strategies develop. Ensuring that environmental safeguards are embedded from the start will be crucial in maintaining public trust and protecting the marine ecosystems we all depend on. As research continues and the pilot gathers more real-world data, SeaCURE’s work will provide invaluable lessons about what is possible, what is practical, and what must be handled with care.
While SeaCURE cannot replace the urgent need to slash emissions at source, it could well become a vital piece of the wider climate puzzle. If it does, it will have started not with grand fanfare, but with a small pipe under a beach in Weymouth, and a few determined scientists refusing to accept that the ocean’s vastness was beyond our ability to protect and restore.
