Seawater carbon storage transforms ocean carbon into building materials like cement and plaster.
What if the answer to fighting climate change and making stronger buildings was flowing all around us—in seawater?
Scientists have developed a new method that could transform how we build everything from roads to homes. By applying electricity to seawater, researchers have found a way to pull carbon dioxide (CO₂) from it and turn it into a solid. That solid can then be used to make eco-friendly concrete, plaster, paint, and other building materials.
Even better, this material doesn’t just reduce carbon emissions; it actively removes CO₂ from the environment. It’s known as seawater carbon storage, and it might be the construction industry’s best hope for a cleaner future.
Cement production is one of the biggest polluters on the planet. It’s responsible for about 8% of global CO₂ emissions—more than all the airplanes in the world combined.
Additionally, to produce traditional concrete, companies extract massive amounts of sand from riverbeds and seafloors. Mining damages ecosystems, ruins coastlines, and hurts fisheries.
But scientists at Northwestern University may have found a better way. Led by Professor Alessandro Rotta Loria, a civil and environmental engineer, the research team discovered how to produce a carbon-negative material using seawater.
The team’s method doesn’t just reduce pollution. It captures carbon dioxide and locks it into a solid mineral that can replace cement and sand in construction.
The researchers employed a process called electrolysis, in which electricity is passed through a liquid to trigger chemical reactions.
They filled a tank with seawater and inserted two metal rods called electrodes. When they ran a small electric current through the water, they also bubbled carbon dioxide into it. This created bicarbonate ions, which are molecules that help trap carbon.
These bicarbonate ions reacted with calcium and magnesium, which are naturally found in seawater. The result? Solid minerals like calcium carbonate and magnesium hydroxide—compounds that can be used in building materials.
In simple terms, the process turns CO₂ into a rock-like substance by using ingredients already present in seawater. This rock can then be added to concrete, plaster, or even paint, helping store the captured carbon for decades.
This breakthrough came from observing nature. Many sea creatures, like coral and shellfish, build their shells by pulling minerals from seawater.
Professor Rotta Loria’s team copied that process using electricity. But unlike coral, which takes years to grow, this new method can make carbon-storing minerals quickly and at scale.
And because the system can be controlled in a lab or factory, it allows scientists to adjust things like mineral size, shape, and texture. That’s important because different construction needs—like walls, sidewalks, or finishes—require different material properties.
One of the biggest advantages of this system is that it can run on renewable energy.
Electrolysis uses electricity, and if that power comes from wind, solar, or hydroelectric sources, the entire operation produces almost zero emissions. This makes seawater carbon storage not just environmentally friendly, but potentially climate-positive.
By using clean energy, scientists can ensure that more carbon is being removed from the environment than is created. That’s what makes the resulting material carbon-negative.
So, how much would this cost compared to traditional concrete?
Right now, that’s unknown. The technology is still being refined. However, researchers believe that once the system is scaled up, it could become competitive with or even cheaper than standard materials. This is especially true if governments support clean construction with carbon credits or green building incentives.
The good news? The entire setup is modular. That means small production units can be placed near coastal areas, where seawater is readily accessible. These units can be multiplied as demand grows.
Professor Rotta Loria’s team is now focused on making the process more efficient so it can be used in real-world construction. Initial indications suggest that the system can scale up while remaining cost-effective and environmentally responsible.
This new method isn’t the only approach to reducing emissions. Other carbon capture technologies focus on trapping CO₂ from smokestacks or the air and storing it underground.
But those systems are often expensive, complex, and hard to maintain. They also don’t turn the captured carbon into anything useful.
That’s where seawater carbon storage stands out. It doesn’t just remove CO₂—it transforms it into valuable building material. That gives it a unique edge in the push for sustainable cities.
Imagine a city where every building contributes to cleaning the atmosphere.
This new method could make that a reality. By replacing traditional cement and sand with carbon-trapping materials from the ocean, builders can create stronger, more sustainable structures.
It’s not just about fighting climate change. It’s about designing a better way to live—starting with the buildings we depend on every day.
If scientists and engineers can make seawater carbon storage affordable and scalable, it could completely change how we think about construction, carbon, and the role our buildings play in the environment.
