The ocean is one of Earth’s most powerful climate regulators. It already absorbs more than 25% of global CO₂ emissions.
But this natural service has a cost. As oceans absorb increasing amounts of carbon dioxide, seawater becomes more acidic, threatening marine ecosystems and marine life.
A new generation of climate technologies is exploring how to remove carbon directly from seawater. One of them is being developed by SeaO2, whose Direct Ocean Capture (DOC) technology will be showcased as a climate solution at ChangeNOW 2026 in Paris.
The concept is simple: use renewable electricity and seawater to extract dissolved CO₂ directly from the ocean.
Why capture carbon from seawater?
The ocean already contains far more carbon than the atmosphere. In fact, seawater holds more than 100 times the concentration of CO₂ per litre compared to air.
This makes the ocean a vast reservoir of carbon — and potentially an efficient place to remove it.
SeaO2’s technology extracts dissolved CO₂ from seawater and returns the treated water back to the ocean. That water can then naturally re-absorb CO₂ from the atmosphere, helping rebalance the carbon cycle.
Removing dissolved carbon locally may also contribute to reducing ocean acidification, offering additional benefits for marine ecosystems.
How Direct Ocean Capture works
SeaO2’s system relies on electrochemistry and vacuum processes to separate carbon dioxide from seawater.
The process involves five main stages:
- Electrochemical production of acid and base solutions
- CO₂ stripping from seawater
- Discharge of decarbonized water back into the ocean
- Atmospheric CO₂ drawdown through natural ocean exchange
- Permanent storage or utilization of captured CO₂
Once extracted, the carbon can be permanently stored, including geological sequestration or mineralization into materials such as concrete. It can also be used as an industrial resource, for example in fuels, chemicals or other low-carbon materials.
Toward gigaton-scale carbon removal
SeaO2 has already demonstrated the technology through a containerized pilot system capable of extracting CO₂ from natural seawater.
The long-term objective is to scale the technology toward gigaton-level carbon dioxide removal, powered entirely by renewable electricity.
Most climate pathways indicate that reaching global climate goals will require both deep emissions reductions and large-scale carbon removal. Ocean-based solutions could become one of the tools helping achieve that balance.
A growing frontier in climate solutions
Ocean carbon removal remains an emerging field, but it is attracting increasing attention from scientists, policymakers and investors.
Solutions like SeaO2 — set to be showcased at ChangeNOW 2026 — illustrate how innovation is expanding the range of technologies aimed at stabilizing the climate.
For decades the ocean has absorbed humanity’s emissions.
Now technology is beginning to explore how it might also help remove them.
Sources
https://www.seao2.com
https://www.seao2.com/technology
https://www.changenow.world
