Could Removing Carbon Dioxide Pollution Improve Ocean Health? Planetary is Exploring the Idea
Nova Scotia’s deep bond with the ocean was first established by the Mi’kmaq people who fished the inlets and estuaries of this rugged coastline for centuries. Today, the ocean still shapes daily life, with roughly 19,000 Nova Scotians working in the seafood industry, making the province Canada’s top seafood exporter.
Climate change is threatening both the coastline and the livelihoods tied to it. Warmer, saltier waters are depleting or relocating populations of fish and shellfish. Rising seas are eroding shorelines and increasing the risks of flooding and storm surge along the province’s 8,000-mile coastline.
It makes sense then that the seaport city of Halifax is home to Planetary Technologies, where a team of scientists are developing a process to make the ocean a solution to the climate threat. By boosting the ocean’s natural ability to absorb and store carbon dioxide (CO₂), they hope to help slow the buildup of CO₂ in the atmosphere and counter ocean acidification.
The technology is called ocean alkalinity enhancement (OAE), and it’s emerging as one of the most promising tools in the fight to remove CO₂ already in the air.
A Scientist Drawn Home by Possibility
That promise was enough to lure Will Burt—then on a comfortable tenure-track path at the University of Alaska—across the continent and back to his native Canada to lead the scientists at Planetary.
In late 2021, while prepping a chemical oceanography lecture, Burt got a call from a friend at Dalhousie University, Burt’s alma mater, who said a Halifax startup needed a chemist. “I had never heard of OAE before I heard about Planetary,” says Burt, now the company’s vice president of science and product. Curiosity led him to the research of Greg Rau, a University of California, Santa Cruz, scientist and Planetary co-founder. “It was so simple, so obvious—I couldn’t believe I hadn’t heard of it,” he says. Within weeks, he’d applied, sold his house, and moved to Halifax. “The chance to get in on the ground floor was just super exciting.”
Turning to the Ocean for Climate Solutions
The science itself isn’t new. The ocean naturally absorbs CO₂ from the atmosphere and converts most of it to bicarbonate, acting as Earth’s biggest climate buffer. Yet even though it spans over two-thirds of Earth’s surface, the ocean cannot keep absorbing the extra greenhouse gases—roughly a quarter of all emissions since the Industrial Revolution—without altering its chemistry. As a result, the water is becoming more acidic, threatening marine life from coral reefs to oyster farms.
OAE is like giving the ocean an antacid. By adding purified, high-alkaline minerals—usually through existing coastal outfalls like the cooling-water pipes at Halifax’s Tufts Cove Generating Station—the seawater becomes slightly more alkaline. That extra alkalinity lets the ocean turn CO₂ into stable dissolved bicarbonate, safely storing it while reducing acidity.
“Your website has to show the science—and the limits of the science. It’s really important not to make big promises.”
Beyond Emissions Cuts: Tackling Legacy Carbon Pollution
Seems simple and obvious, as Burt says, but he adds that until recently, climate change scientists and advocates were laser focused on reducing new carbon dioxide emissions and less interested in removing legacy carbon dioxide pollution. A 2022 report by the Intergovernmental Panel on Climate Change helped expand that focus, asserting the critical need to include carbon dioxide removal and storage in any climate action pathway that aspires to limit global warming to well below 2.0 degrees Celsius above pre-industrial levels—the goal set by the 2015 Paris Agreement.
“It’s a numbers game, honestly. Our progress here has not been good enough and the models are showing that no matter what we do as a society to reduce carbon dioxide we’re still going to have too much of this stuff in the air.”
How Planetary Is Reimagining Ocean-Climate Action
Using existing discharge sites keeps Planetary’s infrastructure costs low and, Burt says, these sites provide convenient locations to insert monitoring systems.
Planetary adjusts the inputs carefully. Sensors track water conditions, and the team fine-tunes dosing to stay well below ecological thresholds. “We know what the ecosystem can handle,” Burt says. “We stay away from those limits.”
Planetary has had some obstacles to overcome, including local opposition to a proposed installation in the UK over fears that the mineral dispersal would be harmful to marine life. Burt says the company had to change the way it communicates about the technology and its use, focusing on community involvement from the outset, and maintaining transparency about the promises and the limitations of the technology.
“Your website has to show the science—and the limits of the science,” Burt says. “It’s really important not to make big promises.”
Early Wins for a Growing Field
Over the past year, Planetary has also earned some public validation: an XPRIZE Carbon Removal XFACTOR Award, and the world’s first carbon credits generated from OAE. And in August, Planetary joined carbon removal fund Frontier in announcing a $31.3 million offtake agreement to remove more than 115,000 tons of CO₂ between 2026 and 2030, using ocean alkalinity enhancement. Carbon credit buyers include British Airways and large tech firms like Google and Stripe.
Burt credits Ocean Visions with increasing public awareness about the connections between climate change and ocean health, as well as the science behind marine carbon dioxide removal. Through its Biennial Summit and events in between, Burt says, the organization is “bringing people from my OAE bubble into the room with stakeholders and decision makers, so that the rest of the world can keep up with the progress.”
Today, the Mi’kmaq and other First Nations still fish the waters as they have for centuries, and in a place as tied to the sea as Nova Scotia, there’s a balance that must be found between innovative technologies and community traditions.
The Confederacy of Mainland Mi’kmaq and the Lennox Island First Nation have been partners with Planetary in OAE research and monitoring. Representatives of these groups were among those offering congratulations in the press release announcing the Frontier deal.
“Our responsibility to the ocean and environment is rooted in generations of knowledge and care,” says Jim Hepworth, CEO of business development and social enterprises for the Confederacy of Mainland Mi’kmaq. “We’re encouraged to see innovative climate solutions, like those being developed by Planetary, approached with attention to both science and community.”
Ocean Visions' mCDR Field Trial Database
Marine carbon dioxide removal (mCDR) field trials are essential to answer key questions about efficacy, durability, measurability, and impact to marine ecosystems and humans. A growing number of field trials performed by research institutions, startups, and others are being conducted in a variety of geographic locations. To increase awareness of the state of development and improve knowledge-sharing across the ocean-climate community, Ocean Visions has built a database of all known field trials currently operating or concluded. The tool includes information on the different mCDR pathways being tested, details of carbon dioxide sequestration, MRV strategy, and lessons learned from the trials. Explore the mCDR Field Trial Database.