- Scientists at USC and Caltech have developed a shipboard system that captures and neutralizes CO₂ emissions using a natural ocean-inspired chemical process.
- The method converts CO₂ into bicarbonate through interaction with limestone, allowing safe discharge back into the sea without harming marine chemistry.
- Lab tests and ocean modeling confirmed the system’s effectiveness and minimal environmental impact, even over long-term, high-frequency shipping routes.
- The technology could reduce up to 50% of emissions from ships, offering a scalable solution alongside other decarbonization strategies.
In a joint effort to address maritime emissions, scientists from the University of Southern California and Caltech, in partnership with the startup Calcarea, have unveiled a shipboard carbon capture system capable of removing up to 50% of carbon dioxide emitted by vessels. The system works by converting the captured CO₂ into a harmless solution that can be safely released into the ocean, offering a potential breakthrough for one of the hardest sectors to decarbonize.
Natural Process with Real-World Impact
The new system draws inspiration from a natural ocean process, replicating a chemical reaction that helps buffer CO₂ in seawater. As ships operate, their exhaust is directed into seawater pumped onboard, slightly increasing the water’s acidity. This CO₂-rich water then flows through a bed of limestone, where the acidity triggers a reaction with the rock, forming bicarbonate — a stable, ocean-safe compound that occurs naturally. Once treated, the CO₂-depleted water is released back into the sea.
This process, though rooted in fundamental marine science, is now being adapted into a practical solution. “What’s most exciting to me is that this started as a pure science question: How does the ocean buffer CO2?” said William Berelson. “From there, we realized we might have a real-world solution that could help fight climate change.”
With maritime shipping contributing nearly 3% of global greenhouse gas emissions, existing alternatives like low-carbon fuels or electrification remain costly or unsuitable for long-distance operations. This system offers a practical alternative. “We see our approach as a complementary strategy that could help ships reduce their environmental impact without major design overhauls,” noted Jess Adkins, Calcarea co-founder and Caltech professor.
Lab Validation and Environmental Safety
In laboratory trials, researchers tested the core components of the system using measured quantities of seawater, limestone, and carbon dioxide. The results closely matched their theoretical expectations, reinforcing confidence in the chemistry and its scalability. “We wanted to show that we not only understood the chemistry — we could also predict how much CO2 would be neutralized,” said Berelson. This validation enabled the team to simulate how the system would perform aboard a working vessel.
To assess environmental impact, the team conducted advanced ocean modeling, simulating a vessel traveling repeatedly between China and Los Angeles over a decade while discharging bicarbonate-rich water along the route. The findings indicated virtually no effect on ocean pH or chemistry — a key confirmation of the system’s safety for marine ecosystems.
According to the researchers, widespread adoption of this technology could cut shipping-related carbon dioxide emissions by up to 50%. “This is the kind of scale we need if we’re going to make a real dent in global emissions,” Berelson noted. “It’s not going to happen overnight, but it shows what’s possible.”
Did you subscribe to our Daily newsletter?
It’s Free! Click here to Subscribe!
Source: USC News
