Can Oceans Absorb Our Carbon Crisis?

On Canada’s eastern shores, beside a gas fired power plant, a little known enterprise is venturing to combat climate change by releasing a slurry of minerals directly into the ocean. The project, spearheaded by Planetary Technologies, underscores the rapidly growing interest in ocean-based carbon removal methods, but whether it’s a transformative climate solution or a dangerous environmental gamble remains fiercely contested.

From the shoreline, a pipeline quietly discharges a milky/white mixture of water and magnesium oxide – a substance widely utilized, from construction to antacids – that Planetary hopes will amplify the ocean’s natural carbon absorbing capacities. A nearby shipping container proudly declares, “Restore the climate. Heal the ocean.”

Planetary Technologies, headquartered in Nova Scotia, is among dozens of ventures racing to harness the oceans’ immense capacity to absorb carbon dioxide. The burgeoning industry has attracted significant funding, including a $1 million investment from Elon Musk’s foundation, with a potential $50 million prize awaiting the most effective carbon-removal method.

Nearly 50 field experiments have taken place globally over the past four years, involving innovative proposals such as sinking mineral rocks, agricultural waste, or seaweed into marine depths to lock away greenhouse gases for centuries. Funding has surged dramatically, with startups securing hundreds of millions of dollars in early investments.

Yet, this emerging field is rife with uncertainty, scientific debate, and regulatory ambiguity. Experts warn that rapidly scaling up these unproven technologies could inadvertently damage ocean ecosystems, emphasizing the urgent need for oversight and measured pace.

“It’s like the Wild West,” remarked Adina Paytan, an earth and ocean science professor at the University of California, Santa Cruz. “Everybody is on the bandwagon, everybody wants to do something.”

Like many peers, Planetary finances its carbon-removal endeavors through selling carbon credits, a practice fraught with controversy due to limited regulation and verification. While the market is flourishing – over 340,000 marine carbon credits were sold last year alone, compared to just 2,000 four years prior – it represents only a fraction of the scale scientists say is required to meaningfully mitigate climate change.

Will Burt, Planetary’s chief ocean scientist, acknowledges uncertainties in this nascent domain, but insists the risk of inaction far outweighs potential pitfalls. “We need to understand if it’s going to work or not. The faster we do, the better,” he said.

An Oceanic Vacuum for Carbon

The urgency to actively remove carbon dioxide has intensified as international climate models repeatedly confirm that emission reductions alone will not suffice to halt global warming. Consequently, the ocean – covering more than 70% of Earth’s surface and already absorbing vast quantities of carbon – has become an attractive frontier for carbon capture.

While terrestrial solutions like reforestation and underground storage have limitations regarding scale and community impacts, the ocean presents an ostensibly limitless carbon sink. Researchers like Adam Subhas from the Woods Hole Oceanographic Institution are evaluating the ocean’s potential role. “Is that huge surface area an option to help us deal with and mitigate the worst effects of climate change?” he wonders.

Planetary’s methodology utilizes magnesium oxide, transforming atmospheric carbon dioxide into stable, ocean-bound compounds. Alternative strategies involve marine flora, such as Gigablue’s project of nurturing phytoplankton in New Zealand waters or initiatives to sink seaweed and agricultural waste in oceanic depths.

Despite Planetary’s assurances that magnesium oxide poses minimal environmental risks – having a history of use in industrial water treatment – scientists and communities remain cautious.

Community Skepticism and Regulatory Hurdles

Public acceptance remains uneven, reflecting apprehension toward ecological impacts. In North Carolina, the company Vesta faced considerable pushback when proposing to deposit olivine – a greenish mineral believed to absorb carbon dioxide – off the coastal town of Duck. Regulatory bodies significantly scaled down Vesta’s ambitions, citing potential harm to marine biodiversity.

Fishing communities, whose livelihoods depend on healthy marine ecosystems, have raised alarms too. A proposal by Woods Hole researchers involving sodium hydroxide near Cape Cod led to prolonged community deliberation. Fishermen expressed concern over potential harm to vulnerable marine life, forcing project leaders to reduce chemical quantities drastically.

Similarly, Planetary itself encountered spirited protests against an ocean carbon capture project in Cornwall, England, prompting a temporary halt and reassessment. Greenpeace scientist David Santillo criticized Planetary’s brief ecological baseline assessment, arguing the data was insufficient for evaluating potential environmental repercussions accurately.

Sara Nawaz, research director at American University’s Institute for Responsible Carbon Removal, notes public skepticism often arises from an emotional attachment to the ocean and the permanence of oceanic interventions. “There’s a fear that once you put something in the ocean, you can’t take it back,” she said.

Scientific Unknowns and Scale Challenges

While the theoretical foundations of ocean based carbon capture have decades of research behind them, practical implementation remains largely untested at meaningful scales. The dynamic nature of ocean currents, marine ecosystems, and carbon cycles complicates accurate measurement and verification.

“The ocean is so hard to get to do what you want it to,” admits Sarah Cooley, a carbon cycle scientist formerly with the Ocean Conservancy.

Dalhousie University’s oceanography chair, Katja Fennel, who monitors Planetary’s work in Halifax Harbour, emphasizes the complexity involved in quantifying carbon sequestration due to the vastness and unpredictability of marine environments.

Questions persist over carbon storage longevity, particularly with organic methods such as algae cultivation or submerged biomass, as their eventual decomposition could return carbon dioxide to the atmosphere. Moreover, meeting international climate goals would necessitate scaling these oceanic projects to an unprecedented extent, raising further environmental and logistical concerns.

David Ho, co-founder of carbon verification non-profit (C)Worthy, summarized the challenge: “What happens when you scale it up to billions of tons every year? That’s still to be determined.”

Racing Against Time

Planetary recently reported capturing 138 metric tons of carbon dioxide, promptly sold as credits to corporate clients such as Shopify and Stripe. While monetizing carbon removal initiatives may raise ethical concerns, experts argue limited government funding leaves few alternatives.

Yet, the urgency cannot be overstated. Last year, global temperatures reached record highs, with carbon emissions continuing to rise.

“We cannot study this solution at the same rate we’ve been studying the problems,” Planetary’s Burt remarked, emphasizing the pressing necessity to accelerate climate action.

As the industry pushes forward, with Planetary capturing 1,000 metric tons of carbon dioxide and other startups expanding their oceanic carbon-removal operations, it remains uncertain how policy shifts – particularly within the United States – may influence future developments.

On April 23, coinciding closely with Earth Day, Elon Musk’s $50 million prize for effective carbon capture will be awarded. Planetary Technologies is among those hopeful contenders, a reflection of both ambition and the urgency of finding viable solutions to climate change in a rapidly closing window.