Newly published research by scientists with the Solid Carbon Project shows that carbon dioxide taken from the atmosphere and injected into the deep subsea floor off Vancouver Island may turn into solid rock in about 25 years.

Solid Carbon, an international research team led by Ocean Networks Canada (ONC), a University of Victoria initiative, and funded by a PICS Theme Partnership grant from the Pacific Institute for Climate Solutions, is investigating how to permanently and safely sequester CO₂ as rock in the ocean floor. 

The project is part of the emerging field of negative emissions technologies—climate solutions that reduce the amount of carbon in the earth’s atmosphere. 

The new research, published this fall in Geochimica et Cosmochimica Acta, the journal of The Geochemical Society and The Meteoritical Society, shows through sophisticated modelling and simulations how captured atmospheric carbon injected into porous, basalt rock, such as that found under the Cascadia Basin, may interact with different minerals in the basalt, creating carbonate rock. 

Keeping a lid on these “ingredients” while this process occurs is the natural layer of sedimentary rock on top of the basalt, composed of up to 800 metres of sandstone and siltstone. This cap keeps the CO₂ interacting with the basalt rather than escaping.

Dr. Benjamin Tutolo, a researcher with Solid Carbon and associate professor in the Department of Geoscience at the University of Calgary, says the research team projects that 25 years post-injection, 95 per cent of the CO2 will be mineralized.

“Once it’s down there, it’s not going to go anywhere for a long time,” he says.

“What we have shown in this study compared to other carbon storage studies is that carbon dioxide can transform to rock within 25 years as opposed to cases where mineralization takes many millennia,” says Dr. Adedapo Awolayo, the research paper’s principal author and a former post-doctoral fellow on the Solid Carbon research team.  

The research also explored uncertainty by creating scenarios where the surface area of basalt that interacted with the CO₂ varied – even with these variations, the researchers still found mineralization could be expected within 100 years.

“The findings from this modelling of ocean basalt lay an incredibly strong foundation for our next steps,” says Kate Moran, ONC’s president and chief executive officer, who notes planning is underway for a Solid Carbon demonstration project in the Cascadia Basin.

If the demonstration project shows positive results, Moran says permanent apparatus could aim to start by injecting half a million tons of CO₂ per year per sequestration site, potentially scaling up to 20+ gigatons per year by 2100 with global deployment of the technology. Human activity adds around 50 gigatons of greenhouse gases to the atmosphere each year.

“It’s important that we do this work now,” Tutolo says, “because projections predict by the middle of the century, we need to be directly capturing 10 gigatons of CO₂ per year out of the atmosphere.”

Tutolo is quick to point out, however, that carbon-capture and-sequestration technology doesn’t remove the need for decarbonization of a variety of industries. 

“This is not a ‘get out of jail free’ card,” Tutolo says. “All pathways to remain under 1.5 degrees of global warming require the use of negative emissions technologies such as this, but we also need to decarbonize the economy to get there. We need both.”

Researchers with the Solid Carbon team are also exploring many other aspects of project implementation, from the best renewable energy source for the project, such as wind power, to the policy implications for various levels of government, and how best to involve communities and Nations who use and care for the Cascadia Basin.

Learn more about the Solid Carbon project team and history at solidcarbon.ca.