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How new technology could turn oceans into a giant 'sponge' for carbon dioxide

Equipment on a barge for UCLA's SeaChange climate change carbon removal project at the Port of Los Angeles in San Pedro, California on April 12, 2023. - Floating in the port of Los Angeles, a strange-looking barge covered with pipes and tanks contains a concept that scientists hope to make waves: a new way to use the ocean as a vast carbon dioxide sponge to tackle global warming.
Scientists from University of California Los Angeles (UCLA) have been working for two years on SeaChange -- an ambitious project that could one day boost the amount of CO2, a major greenhouse gas, that can be absorbed by our seas. (Photo by Patrick T. Fallon / AFP) (Photo by PATRICK T. FALLON/AFP via Getty Images)
Equipment on a barge for UCLA's SeaChange climate change carbon removal project at the Port of Los Angeles in San Pedro, California. (Getty Images)

Our planet's oceans already absorb a vast amount of carbon dioxide and warmth caused by climate change, but could a new technology turn them into a giant "sponge" for CO2?

That's the aim behind SeaChange, a project masterminded by researchers from the University of California Los Angeles (UCLA).

SeaChange pilot plants turn CO2 absorbed by the ocean into minerals, leaving the ocean free to absorb more.

Researchers believe that around 1,800 industrial-scale plants would capture about 10 billion tonnes of atmospheric carbon dioxide per year – almost a third of the 37 billion tonnes released annually.

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The project's goal is to "to use the ocean as a big sponge", says Gaurav Sant, lead researcher and the director of the Institute of Carbon Management (ICM).

Sant said: "The oceans are the world's largest sink of carbon dioxide emissions.

"This technology can electrochemically enhance and restore the oceans' capacity for carbon dioxide removal from the atmosphere at a globally relevant scale, thereby mitigating ongoing and accelerating climate change."

Equipment including an electrochemical reactor where seawater is split via electrolysis to capture carbon on a barge for UCLA's SeaChange climate change carbon removal project at the Port of Los Angeles in San Pedro, California on April 12, 2023. - Floating in the port of Los Angeles, a strange-looking barge covered with pipes and tanks contains a concept that scientists hope to make waves: a new way to use the ocean as a vast carbon dioxide sponge to tackle global warming.
Scientists from University of California Los Angeles (UCLA) have been working for two years on SeaChange -- an ambitious project that could one day boost the amount of CO2, a major greenhouse gas, that can be absorbed by our seas. (Photo by Patrick T. Fallon / AFP) (Photo by PATRICK T. FALLON/AFP via Getty Images)
An electrochemical reactor where seawater is split via electrolysis to capture carbon on a barge for UCLA's SeaChange climate change carbon removal project. (Getty Images)

Two pilot plants will take-in sea water, which holds more than 150 times as much carbon dioxide as air does, and convert the dissolved CO2 into two minerals – solid limestone and brucite (the mineral form of magnesium hydroxide).

It’s a process similar to how some marine organisms form seashells.

The outgoing seawater, depleted of CO2, is then able to absorb more of the greenhouse gas just like a sponge, rinsing and repeating the same process.

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It also yields hydrogen gas as a co-product, which can be used as a clean fuel.

UCLA professor Dante Simonetti, also ICM's associate director for technology translation, said: "These projects will define protocols and strategies for measurement, verification and optimal project siting.

"They will also help us develop operational best practices to ensure scalable, cost-effective and durable carbon dioxide removal.

"The successful operation of these plants will lead to the rapid adoption of this technology at much larger scales."