About a decade ago, headlines ran rampant about a Californian entrepreneur who dumped 100 tons of iron filings into the Pacific Ocean. 

The entrepreneur did that to trigger a spike of growth of phytoplankton that could absorb CO2 as they live. They could then sink to the ocean floor when they die, potentially helping against climate change.

At that time, the project unfortunately faced heavy criticism. Critics labeled it as an unscientific stunt that endangered marine ecosystems. They added that such an effort doesn’t ensure the permanent removal of carbon from the atmosphere.

This criticism further hindered other efforts to turn to oceans for reducing carbon. They were associated with rogue geoengineering experiments and questionable green business ventures.

Well, a lot has changed within a decade, and now the paradigm has shifted.

Currently, more climate scientists have come to agree that our planet needs several ways to lessen the severe impacts of global warming. 

Because if those efforts succeeded, we could reduce the cost of carbon capture significantly, helping us further in the fight against climate change. 

T. Alan Hatton at the Massachusetts Institute of Technology (MIT) stated that the oceans could serve as Earth’s primary “carbon sink.” The planet could absorb 30 to 40% of the greenhouse gas from the atmosphere.

This inherent capacity of the oceans simplifies the carbon capture process. 

Hatton explained that the density of CO2 in the oceans was over 100 times greater than in the air. This means that the handling of materials is much more manageable compared to air-based operations. 

Basically, there’s an advantage in ocean capture that could make the entire process more efficient.

In this turn of events, venture capitalists have now funded initiatives that utilize ocean chemistry to combat climate change. Such efforts have attracted financial support, particularly since major corporations want to offset their emissions nowadays. 

Experts stated that the world’s oceans serve as a remarkable carbon sink. When these new projects promise to enhance this capacity, they offer hope in a world struggling with escalating emissions.

One thing to note, though, is that these recent initiatives stand in a delicate situation regarding the climate. The companies involved–land or ocean-based–operate at a scale that will make a significant dent. 

According to some experts, even with significant expansion, carbon removal technology alone won’t be enough without substantial emissions reductions. 

In addition, they expressed worry that getting too focused on carbon removal could shift attention from reducing emissions.

Right now, what’s happening in the world is that emission reductions are lagging. 

 

 

Consequently, that raises the potential need to remove massive tons of carbon from the atmosphere within the next 30 years. And in turn, more investments are necessary to ensure that there will be enough technology to address such a challenge. 

Previously, land-based carbon removal companies got all the rave and attention, like Climeworks and Carbon Engineering, for example. They’ve attracted substantial venture capital to develop large machines that capture carbon from the air and store it underground.

But now, as mentioned, new companies and startups focusing on ocean-based solutions have garnered substantial funding. 

Still, there are lingering concerns about the potential impact on ecosystems and the long-term impact of carbon deposit in oceans.

The ocean-focused startups are doing these efforts in various methods. 

For one, Ebb Carbon aims to enhance ocean water’s alkalinity to increase carbon dioxide absorption. It has secured $20 million in recent venture capital backing. 

RunningTide plans to sequester CO2 with seaweed. It has signed a deal with Microsoft to remove 12,000 tons of CO2.

Captura seeks to extract dissolved CO2 from ocean water for storage underground or industrial use. It has received a $12 million investment financial support.

In its carbon extraction process, Captura starts by piping seawater to a reactor. This reactor uses electricity to split water molecules into positively charged protons and negatively charged hydroxyl ions.

Together, the compounds react with sodium and chloride ions in the water. The reaction produces hydrochloric acid and sodium hydroxide, a base.

Then, the acid reacts with bicarbonate ions in the water. This causes carbon to bubble out into a storage tank. 

Next, sea water meets the base which neutralizes the acid before the waste gets discharged back into the ocean. The base is then ready to absorb more carbon.

I should note that the waste or the whole process doesn’t add anything into the ocean environment. The only output, according to Captura, is carbon and decarbonized water.

Another company is called Equatic, the brainchild company of UCLA. It combines direct air carbon capture principles with alkalinity enhancement.

It has a pilot plant in LA that separates seawater into oxygen and hydrogen using electricity. The plant then separates and manipulates the sea water’s pH levels to release carbon as solid minerals.

Despite also starting with an electricity-fed reactor like Captura, Equatic’s process takes a different approach. 

In Equatic’s process, alkaline rocks play a part in neutralizing the acid. The base causes dissolved CO2 to form bicarbonate. It also makes magnesium and calcium ions to precipitate out as solid carbonates which at the end removes carbon.

 

 

One can use the carbonates as ingredients for cement and other industrial products. In addition, the reactor also produces hydrogen gas, which as we know, a carbon-free, valuable, green energy source. 

Equatic states that the plant removes about 100 kilograms of CO2 daily, with plans for a larger-scale operation. It sounds hopeful, long-term speaking, but experts say this output remains a fraction of the global carbon issue. 

However, Equatic’s chief operating officer Edward Sanders stated that the oceans could soon play a major part in preventing climate catastrophe.

“There’s 38,000 gigatons of dissolved organic carbon in the oceans today. That’s an extraordinary amount. So we’re confident that if we were to use the Equatic process, then the [carbon] capacity is there.” Sanders said. 

According to Sanders, the remaining problem is finding a way to scale up the company’s technology quickly enough to make a difference. 

Concerns about efficacy and implications for marine environment

Skeptics (some other experts) worry that companies pursuing carbon removal may be moving a bit too fast. 

There are many unanswered questions regarding the potential impacts of different methods on marine life and ecosystems. This includes fish populations crucial for food security.

For instance, it’s still uncertain as to how large-scale floating kelp farms have consequences to the marine ecosystems.

Also, there’s the scientific uncertainty surrounding the effectiveness of proposed carbon sequestration in oceans.

Matthew Long, a scientist at the federally funded National Center for Atmospheric Research, emphasizes the lack of sophisticated computer models needed for companies to accurately measure their carbon trapping in the ocean. 

Long is seeking around $50 million in philanthropic funding to develop such models, highlighting the urgent need for scientific collaboration.

On the other hand, science advisor Sifang Chen stated that Equatic was a company with more certainty about its carbon sequestration methods. 

According to Chen, it’s because the company directly mixes carbon into seawater in their plants. 

At the same time, Chen worries that other companies sell carbon removal credits without enough proof of effectiveness. In addition, there’s also a lack of regulation for ocean carbon removal projects.

She’s concerned that unregulated experimentation could lead to public backlash. When that happens, trust in the industry will diminish before it can gain momentum. Therefore, Chen encourages further, clearer research to establish trust and effectiveness in ocean carbon removal. 

From a layman perspective, I believe that both ocean and land carbon sequestration could be one of the many feasible solutions to combat climate change. 

Sure, it might divert people’s attention from actually reducing carbon footprint, but I mean, there are still some other ways to encourage that anyway. 

But hey, I’m not an expert who can either be skeptical of or welcoming the novel, ocean-based carbon sequestration efforts.  So, what do you think of this situation?

 

Sources

https://time.com/6290814/ocean-carbon-removal-industry/
https://www.science.org/content/article/startups-aim-curb-climate-change-pulling-carbon-dioxide-ocean-not-air
https://www.scientificamerican.com/article/scientists-are-trying-to-pull-carbon-out-of-the-ocean-to-combat-climate-change/