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Exploring responsible uses of the ocean to address our climate crisis

Every year, humans pump about 40 billion tons of carbon dioxide into the atmosphere. The heat from this greenhouse gas is disrupting planetary systems and reshaping life on Earth. The ocean may be able to help us reverse this trend, but we need to proceed with caution.

Ocean Iron Fertilization:
A part in the solution to climate change?


In prior studies, iron was added in liquid form from the stern of a moving ship.


Adding iron can stimulate growth of marine phytoplankton, microscopic, plant-like organisms.


The bloom of phytoplankton serves as food for zooplankton, such as krill, which feed other animals higher on the food chain.

Marine Snow

Particles made up of dead plankton and fecal pellets form larger clumps of carbon-rich material called marine snow that slowly sink into the deep ocean. 


Less than 1% of marine snow makes it to the deep ocean and is buried in seafloor sediments.

Diel Vertical Migration

Some of the sinking carbon is moved through the twilight zone as part of a massive, daily movement of marine life known as the diel vertical migration.


Most of the carbon that sinks is remineralized, meaning it is converted to a different form as mid-water animals feed on sinking marine snow particles.

CO2 mixing time scales

The time it takes for carbon to return to the surface (and possibly back to the atmosphere as CO2) depends on how deep it sinks in the ocean.

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The ocean, which covers more than 70% of our planet, may be able to help. In a few key parts of the ocean, biological activity is limited by a lack of iron in seawater. Adding iron could, therefore, help spur growth of phytoplankton and increase both the uptake of carbon dioxide by the ocean and the amount that gets sequestered at depth.

Science needs to lead the way, by providing the greatest possible insight into both the intended and unintended consequences, as well as the long-term effectiveness of adding iron to the ocean.

The decisions we make today will shape the future of generations to come.

What is our plan?

The purpose of the ExOIS consortium is to resolve the impact of enhanced iron fertilization on marine ecosystems and its potential for removal of atmospheric carbon dioxide.

We are in a climate crisis. There is international agreement that to limit warming to 2°C we need both climate mitigation (emissions reduction) and intervention (Carbon Dioxide Removal- CDR) in order to achieve “net negative emissions.”

We believe that enhancing the ocean’s natural biological carbon pump may be a responsible way to help control increases in atmospheric carbon dioxide. We are encouraged by analyses of natural and deliberate ocean iron fertilization (OIF) field experiments that have demonstrated low deployment costs and high global capacity of OIF, up to Gt CO2/yr scales, and even higher if a wider range of settings are considered.

However there remain many uncertainties about the ecological consequences, the efficiencies and permanence of enhanced carbon sequestration, and whether it is a practical approach to provide quantifiable climatic benefits.

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Moving ahead requires deliberate field studies that are both guided and inform mechanistic models to demonstrate the efficacy and potential risks of OIF at scale. Exploring Ocean Iron Solutions will require partnerships for scientific research as well as with public and private partners for funding. We will follow our five guiding principles for ocean CDR which promote responsible and transparent research as we assess the potential intended and unintended consequences, while considering the social implications and collective benefit of ocean CDR. The consequences of OIF will be weighed against other climate intervention approaches and the suffering and harm brought on by human induced climate change.


Our guiding principles

  1. Promoting collective benefit

  2. Establishing responsibility and liability

  3. Open and cooperative research

  4. Iterative evaluation and assessment

  5. Public involvement

Who We Are

Steering Committee

Ken Buesseler
Woods Hole Oceanographic Institution
Kilaparti Ramakrishna
Woods Hole Oceanographic Institution
Joo-Eun Yoon
Korea Polar Research Institute
Mark Wells
University of Maine
Sarah Smith
Moss Landing Marine Laboratories
Fei Chai
Xiamen University

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