In some key parts of the ocean, biological activity is limited by a lack of iron in seawater. Adding iron could therefore help stimulate phytoplankton growth and increase both the ocean’s uptake of carbon dioxide and the amount sequestered at depth. Credit: Natalie Renier, Woods Hole Oceanographic Institution Francisco Martin Leon 22/09/2024 11:30 7 min
Although the urgent reduction of carbon dioxide (CO2) and other greenhouse gas emissions is necessary as a main activity to stop climate change, there is a broad consensus on the need to remove the CO2 that is already in the atmosphere. Given its enormous role in CO2 storage, it cannot be ignored. the ocean’s potential for marine carbon dioxide removal (marine carbon dioxide removalmCDR) and help improve our stressed climate system.
Several of the world’s leading scientific bodies, including the Intergovernmental Panel on Climate Change and the National Academies of Sciences, Engineering, and Medicine, identified iron fertilization of the oceans (ocean iron fertilizationOIF) as an emerging climate solutionand more than 400 scientists signed a letter calling for expanded research on mCDR.
Governments around the world have invested tens of millions of dollars to promote ocean-climate solutions, signaling the need for the public sector, philanthropy and academia to explore the role of the ocean in mitigating the effects of climate change.
Now, an article published in the magazine Frontiers in Climatetitled in Spanish “Next steps to evaluate ocean iron fertilization for marine carbon dioxide removal“, details the work needed to Evaluate the potential of OIF as a low-cost, scalable and rapidly deployable mCDR method.
According to an international group of experts called “Exploring Ocean Iron Solutions” (ExOIS), which is organized around a code of responsible conduct, it is necessary to study the OIF to determine whether it is an efficient and environmentally and socially responsible method of mCDR.
“This is the first time in more than a decade that the marine science community has come together to support a specific research plan for ocean iron.“said the lead author, Ken BuesselerExecutive Director of the ExOIS program and Senior Scientist in the Department of Marine Chemistry and Geochemistry at Woods Hole Oceanographic Institution (WHOI).
What is iron fertilization of the oceans?
OIF is a technique that consists of Adding small amounts of a micronutrient, iron, to the ocean surface to promote the growth of marine plants or phytoplankton. This growth removes CO2 from the atmosphere, and as plankton die or are eaten, they transfer some of that carbon as sinking particles to be stored in the deep ocean. While large amounts of iron enter the ocean naturally, The OIF is an effort to accelerate that process.
“Given the ocean’s large capacity to store carbon (more than 50 times greater than the atmosphere and 15 to 20 times greater than all terrestrial plants and soils), consideration should be given to enhancing the ocean’s natural capacity to store carbon.“, according to Paul Morrisproject manager for the ExOIS program, an independent program hosted at WHOI.
“Even if we could stop carbon emissions today, we would still need marine RDF because of all the greenhouse gas CO2 already in the atmosphere.“Buesseler said.
To advance understanding of the suitability, effectiveness and impacts of the OIF, Researchers focus on five key activities: field studies in the northeast Pacific Ocean; regional, global and field modelling; testing of various forms of iron and delivery methods, which have different advantages and disadvantages; advances in monitoring, reporting and verification (monitoring, reporting, and verificationMRV) for carbon and eMRV (which focuses on examining ecological changes); and advances in social science and governance efforts to go hand in hand with physical science efforts.
The article states that it is necessary field studies to fill knowledge gaps and address uncertainties about whether OIF is sufficiently effective, scalable and reproducible for mCDR. The authors said that field experiments should be significantly larger and longer in duration compared to previous OIF studies.
Even at these larger pilot scales, permanent changes are not expected, as iron is rapidly and naturally depleted and mixed into the ocean. The amount of iron added during field experiments will be thousands of times less than the amount of iron added naturally to the ocean.as occurs during volcanic eruptions. However, increasing the scale provides the ability to better quantify the reduction in CO2 at the ocean surface, while assessing the ecological and environmental consequences.
Modeling is needed for experimental planning, to synthesize the results of field trials, and to predict and extrapolate the results to regional and global scales, which will be necessary to assess carbon impacts, climate effects, and overall changes in the carbon cycle and the ocean ecosystem.
Reference
Ken O. Buesseler et al, Next steps for assessing ocean iron fertilization for marine carbon dioxide removal, Frontiers in Climate (2024). DOI: 10.3389/fclim.2024.1430957
This entry was posted in News on 22 Sep 2024 by Francisco Martín León
