HALIFAX, Nova Scotia (AP) — A growing industry is racing to engineer a solution to global warming using the absorbent power of the oceans. Dozens of companies and academic groups are pitching the same theory: that sinking rocks, nutrients, crop waste or seaweed in the ocean could lock away climate-warming carbon dioxide for centuries or more. Nearly 50 field trials have taken place in the past four years, with startups raising hundreds of millions in early funds. But the field remains rife with debate over the consequences for the oceans if the strategies are deployed at large scale, and over the exact benefits for the climate. Critics say the efforts are moving too quickly and with too few guardrails.
Planetary Technologies is one of the companies at the forefront of this exciting but contentious effort. The Nova Scotia-based firm is pumping a slurry of minerals into the ocean near a gas-fired power plant in an attempt to combat climate change. Planetary Technologies uses magnesium oxide to transform carbon dioxide from a gas into stable molecules that won’t interact with the atmosphere for thousands of years. Their motto, “Restore the climate. Heal the ocean,” reflects their ambitious objectives.
This initiative is part of a wider movement that has garnered the support of influential figures, including $1 million from Elon Musk’s foundation and an opportunity to compete for an additional $50 million prize. The ocean has a significant potential to absorb heat and carbon; many argue that utilizing its vast area can help mitigate the effects of climate change. However, experts, including Will Burt, Chief Ocean Scientist at Planetary, acknowledge that while they are venturing into uncharted territory, the bigger risk lies in inaction.
“We need to understand if it’s going to work or not. The faster we do, the better,” Burt stated. While the numbers are compelling, with the industry selling over 340,000 marine carbon credits last year—up from just 2,000 four years ago—the total amount of carbon removal remains a tiny fraction of what scientific consensus dictates is necessary for a livable planet.
Efforts in ocean carbon capture are varied. Many companies are working on diverse strategies ranging from using magnesium oxide to sink rocks, nutrients, crop waste, and even seaweed into the ocean to lock away carbon. The Woods Hole Oceanographic Institution is also exploring chemical solutions, having proposed a project that initially sought to pour 66,000 gallons of sodium hydroxide solution into ocean waters, which was later downsized to less than 17,000 gallons due to community pushback.
While some coastal communities express skepticism and resistance, especially regarding the potential impact on local fisheries, others are enthusiastic about participating in climate solutions. The North Carolina-based Vesta, which promotes olivine for carbon capture, discovered this tension firsthand when regulatory scrutiny forced them to downsize a project that involved dumping large quantities of olivine near a beach.
More than a hundred people protested against a Planetary project in Cornwall, England, highlighting that while there is broad enthusiasm for marine carbon capture, community concerns around potential risks cannot be dismissed. Under scrutiny, Planetary has paused its plans to pump minerals into Cornwall and assured locals it wouldn’t sell carbon credits from its past chemical releases.
Even with the uncertainties surrounding these experiments, scientists recognized the urgency of their work. “There’s an urgency to move ahead and conduct this work,” urged Ken Buesseler of the Woods Hole Oceanographic Institution.
The complexity of ocean dynamics makes predicting the efficacy of carbon capture methods difficult. Many strategies are still in their infancy, and companies like Carboniferous, which aims to sink sugarcane pulp to the seafloor, encounter logistical hurdles when trying to scale their initiatives.
For instance, Planetary Technologies managed to capture 138 metric tons of carbon in late 2024, marking a significant milestone for the company. Recently, they announced reaching an impressive total of 1,000 metric tons of captured carbon. This achievement reflects a growing commitment among entrepreneurs and researchers who see ocean-based carbon removal as a pivotal part of addressing climate change.
Yet the path to large-scale solution implementation runs into obstacles that include funding challenges and the scrutiny of environmental regulations. Without adequate investment and governmental support, the ocean carbon capture sector faces an uphill battle.
During a recent EPA listening session on the Woods Hole project, the potential environmental risks were balanced against the perceived scientific merit of the initiatives. While the EPA regarded the risk as acceptable, the perception of potential harm remains deep-rooted among fishing communities, which raises the essential question: can innovative climate strategies proceed without further compromising local ecosystems?
There’s still plenty of skepticism, highlighted by critics like Adina Paytan of the University of California, Santa Cruz, who cautions that rapid initiatives could lead to unintended environmental consequences. “It’s like the Wild West. Everybody is on the bandwagon, everybody wants to do something,” she warned.
The solution to the climate crisis might reside in maintaining open lines of communication with communities impacted by these projects. For companies involved in ocean carbon capture, building trust is essential if they want their efforts to be successful long-term. “It’s more the start of a dialogue with regulators and the community,” said Tom Green, CEO of Vesta.
The clock continues to tick down on our planet's health. As carbon emissions are projected to reach new highs, research into new strategies becomes increasingly crucial. Climate scientists propose that nearly two-thirds of the world’s coastlines may need to embrace initiatives like seaweed farms to make a significant impact.
As the industry seeks to address this climate challenge, the future remains uncertain but full of potential. There are pressing needs for innovative research, as Planetary Technologies hopes their results will pave the way for broader acceptance of ocean-based carbon removal. The extent to which these initiatives can address climate change may ultimately require us to rethink our relationship with the oceans that regulate our climate.
