We present a cost model for implementing a deployment scale effort for conducting ocean iron fertilization (OIF) for marine-based carbon dioxide removal (CDR). The model incorporates basic oceanographic parameters critical for estimating the effective export of newly fixed CO₂ into biomass that is stimulated by Fe addition to an Fe-limited region of the Southern Ocean. Estimated costs can vary by nearly 100-fold between best-case and worst-case scenarios, with best-case values of $7/net tonne C captured versus worst-case $1,500/net tonne C captured, without accounting for verification costs. Primary oceanographic factors that influence cost are the net primary productivity increases achieved via OIF, the amount of C exported into the deep ocean, and the amount of CO₂ ventilated back to the atmosphere. The model compares ship-based versus aerial delivery of Fe to the ocean, and estimates aerial delivery can be 30%–40% more cost effective; however, the specific requirements for aerial delivery require additional research and development. The model also estimates costs associated with verification and environmental monitoring of OIF. These costs increase $/net tonne C captured by 3–4-fold. Best, intermediate, and worst cases for aerial delivery and ship delivery are $21, $83, $2,033, and $24, $94, $4,691, respectively, inclusive of verification costs. The primary goal of this model is to demonstrate the variability in cost of OIF as a CDR method, and to better understand where additional research is needed to determine the major factors that may make OIF a tractable, nature-based CDR method.

中文翻译：

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作为二氧化碳去除手段的海洋铁肥成本模型，比较船载和空载运输，并估算验证成本

我们提出了一个成本模型，用于实施海洋铁肥化（OIF）以实现基于海洋的二氧化碳去除（CDR）的部署规模工作。该模型纳入了基本海洋学参数，这些参数对于估计新固定的 CO ₂向生物量的有效输出至关重要，而生物量是通过向南大洋铁有限区域添加铁来刺激的。最好情况和最坏情况之间的估计成本可能相差近 100 倍，最好情况下捕获的净吨 C 价值为 7 美元/净吨 C，最坏情况下捕获的价值为 1,500 美元/净吨 C，而不考虑验证成本。影响成本的主要海洋因素是通过OIF实现的净初级生产力增加、输出到深海的C量以及排回大气的CO ₂量。该模型比较了通过船载和空中向海洋输送铁，并估​​计空中输送的成本效益可提高 30%–40%；然而，空投的具体要求需要额外的研究和开发。该模型还估算了与 OIF 验证和环境监测相关的成本。这些成本使捕获的每净吨 C 美元增加了 3-4 倍。空运和海运的最佳、中等和最差情况分别为 21 美元、83 美元、2,033 美元和 24 美元、94 美元、4,691 美元，包括验证费用。该模型的主要目标是证明 OIF 作为 CDR 方法的成本变化，并更好地了解需要进行哪些额外研究来确定可能使 OIF 成为易于处理、基于自然的 CDR 方法的主要因素。