A nonprofit formed by Mike Schroepfer, Meta’s former chief technology officer, is spinning out a new organization dedicated to accelerating research into ocean alkalinity enhancement—one potential means of leveraging the seas to suck up and store away even more carbon dioxide.
Additional Ventures, cofounded by Schroepfer, and a group of other foundations have committed $50 million over five years to the initiative, dubbed Carbon to Sea. The goals of the effort include eventually conducting small-scale field trials in the ocean, advancing policies that could streamline permitting of those experiments, and developing technology such as the sensors and models necessary for accurately measuring and monitoring the effect of such interventions.
The seas already act as a powerful buffer against the worst dangers of climate change, drawing down about a quarter of human-driven carbon dioxide emissions and absorbing the vast majority of global warming. Carbon dioxide dissolves naturally into seawater where the air and ocean meet. But scientists and startups are exploring whether these global commons can do even more to ease climate change, as a growing body of research finds that nations now need to both slash emissions and pull vast amounts of additional greenhouse gas out of the atmosphere to keep warming in check.
Ocean alkalinity enhancement refers to various ways of adding alkaline substances, like olivine, basalt, or lime, into seawater. These basic materials bind with dissolved inorganic carbon dioxide in the water to form bicarbonates and carbonates, ions that can persist for tens of thousands of years in the ocean. As those CO2-depleted waters reach the surface, they can pull down additional carbon dioxide from the air to return to a state of equilibrium.
The ground-up materials could be added directly to ocean waters from vessels, placed along the coastline, or used in onshore devices that help trigger reactions with seawater.
Carbon to Sea is effectively an expansion of the Ocean Alkalinity Enhancement R&D Program, which Additional Ventures launched in late 2021 with the Astera Institute, Ocean Visions, the Grantham Environmental Trust, and others. Early last year, the organizations began accepting applications for research grants for “at least $10 million” that could be put to use over the next five years. The program has committed $23 million to the research field so far.
Antonius Gagern, the program director for ocean carbon dioxide removal at Additional Ventures, will lead the new organization.
“In looking at the different ways that the ocean is already using natural carbon pumps to sequester CO2 permanently, ocean alkalinity enhancement has emerged as, for us, the most promising one for a number of reasons,” Gagern says.
It’s “extremely scalable,” it’s “very permanent,” and it “doesn’t mess with” biological systems in the ways that other ocean-based approaches may, he adds.
‘A substantial climatic impact’
Other observers also consider ocean alkalinity enhancement a promising approach, in part, because it’s one of the major ways that the planet already pulls down carbon dioxide over very long time scales: rainwater dissolves basic rocks, producing calcium and other alkaline compounds that eventually flow into the oceans through rivers and streams.
These processes naturally sequester hundreds of millions of tons of carbon dioxide per year, by some estimates. And the planet has more than enough of the reactive materials required to bond with all the carbon dioxide humans have emitted throughout history.
There are potentially some additional benefits as well. Alkaline substances could also reduce ocean acidification locally and might provide nutrients beneficial to certain marine organisms.
Andreas Oschlies, a climate modeler at the Helmholtz Centre for Ocean Research in Kiel, Germany, agrees that it’s one of the few carbon removal approaches that could “really deliver at scale and have a substantial climatic impact.”
“The minerals are not limiting and the reservoir, the ocean, is not limiting,” he says.
(Oschlies hasn’t received research grants from the Additional Ventures consortium but is a senior advisor to a project that has.)
But he’s also quick to stress that there are significant challenges in scaling it up, and that far more research is needed to understand the most effective approaches and secondary impacts of such interventions.
Notably, it would require mining, grinding, and moving around massive amounts of alkaline materials, all of which entails a lot of energy and environmental impacts.
“It’s a huge operation, of course, similar to fossil fuels or coal mining,” he says. “So these are all side effects we have to take into account.”
There are additional challenges and uncertainties as well.
Several recent lab experiments found that these approaches didn’t work as well or easily as expected. Indeed, in some instances the addition of such substances reduced alkalinity as well as the uptake of carbon dioxide. This raises the possibility that the methods may only work in limited areas or circumstances, or could be more costly or complex to implement than hoped.
Some of the minerals could add heavy metals into delicate marine ecosystems. They could also alter the light conditions and biogeochemistry of the waters in ways that might harm or help various organisms.
Finally, the fact that carbon removal happens as a second step in the process makes it challenging to accurately monitor and measure how much CO2 the process really removes, particularly with approaches that occur in the turbulent, variable open oceans. That, in turn, could make it difficult to incentivize and monetize such efforts through carbon markets.
CarbonPlan, a San Francisco nonprofit that evaluates the scientific integrity of carbon removal approaches and projects, ranks ocean alkalinity enhancement on the low end of its “verification confidence levels,” which evaluate the degree to which long-term carbon removal and storage “can be accurately quantified” with existing tools and approaches.
This is a developing story, and will be updated.
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