The method

OIF involves adding iron to ocean waters to stimulate phytoplankton growth, which absorbs CO₂ via photosynthesis. When phytoplankton die, some carbon sinks to the deep ocean, potentially sequestering it for millenia. Some carbon is bound to increased marine biota with lifespans up to a hundreds of years.

Iron is a limiting nutrient in many parts of the ocean. By adding iron, OIF triggers phytoplankton blooms that absorb CO₂. A portion of this biomass sinks, locking carbon away in deep waters or sediments.

Estimates vary, but large-scale OIF could remove hundreds of millions to billions of tons of CO₂ annually—making a significant contribution to climate mitigation. For comparison: EU (27 countries) CO₂ emissions 2023 was 2,4 billion tons.

Yes, iron inputs from sand dust storms, wildfire ash or volcanic ash naturally fertilize the ocean. Ocean iron fertilization mimics these processes but on a controlled scale. (Langmann et al. 2010)

OIF is more scalable and significantly more cost-effective than other direct air capture technologies but is less predictable and cannot be similarly controlled compared to technologies in closed-systems.

Depending on ocean currents and depth, sequestered carbon can remain for decades to millenia, part of the carbon returns to the atmosphere over time.

For carbon to be considered “permanent,” it would need to stay sequestered for over 1,000 years. While some percentage of the CO₂ is estimated to be locked away this long, much of it will re-enter the atmosphere over centuries through natural upwelling and respiration processes.

1-20% of the CO₂ captured by phytoplankton ultimately is estimated to reach deep waters or sediments. The rest cycles back into surface waters, limiting sequestration efficiency.

It could contribute meaningfully but not solve climate change alone. OIF should be considered as part of a broader portfolio of carbon removal strategies.

We emphasize that OIF is not giving an excuse to continue polluting, but is rather a means to remove legacy emissions and provide support for biodiversity. We are also aware of the fact that even if we stopped burning fossil-fuels today, there is over 2 teratons of excess CO2 in the atmosphere. To put this into context, 2 teratons is about 50 times the annual global emissions. Hence, we need to find ways to remove that excess CO2.

If done in the wrong location (i.e too close to coasts) or during the wrong time (i.e if water temperature is over 20 degrees) risks might include, temporary oxygen depletion, food web and biodiversity disruptions, increased production of climate-relevant gases like methane and nitrous oxide, or possible unintended harmful algal blooms (HABs). Oceanry’s key goal is to develop global standardization and regulation to make sure iron fertilization is done in a safe and controlled way. Oceanry favors to use inert, inorganic geological material, which is whitelisted under the London Protocol.

Careful choice of experiment deployment area will help reduce the risk of harmful algal blooms:

• Avoiding high nutrient areas, with elevated surface water temperature will reduce harmful algae bloom (HAB) risk.
• Deployments at high seas, in remote locations, away from the influence of coastal runoff nutrients are preferred.
• Deployment in cooler waters, further away from equatorial areas will reduce risk of HABs.
• Deployments in different times of the year, in closeby regions will help balance out the impacts of a single experiment.
• Natural inert, inorganic geological material are preferred for the source of iron.

Hydrocarbon production shall be researched to understand cloud production mechanisms (through isoprene and other cloud condensation nuclei) and potential methane and other greenhouse gas production. Multidisciplinary research shall be carried out to understand short- and mid-term impacts, research starting before deployment and ending 5 years after the deployment. It is expected that no visible signs will be left one year after the deployment.