The increasing exigency of climate change necessitates the exploration of various carbon dioxide removal (CDR) methods to reduce greenhouse gas emissions. As the ocean covers 70% of the Earth's surface and has absorbed approximately 25% of all human CO2 emissions since the industrial revolution, it presents a significant potential to achieve global carbon dioxide removal targets.
Ocean-based CDR (oCDR) techniques, such as Ocean Alkalinity Enhancement (OAE) and marine afforestation, promise to increase the rate of CO2 absorption. OAE, an approach to increase the CO2 absorption potential of seawater by raising its pH, shows great potential in offsetting the negative impacts of ocean acidification. Additionally, marine afforestation strategies, including macro-algae cultivation and burial, have potential for carbon sequestration while also providing economic benefits from biofuels and food production.
However, significant gaps in understanding these techniques' effectiveness, scalability, environmental impacts, and monitoring requirements limit their implementation on climatically significant scales. Therefore, ongoing research and trials are necessary to address these knowledge gaps.
Moreover, the oCDR sector faces considerable legal, ethical, and political challenges that could influence its implementation and scalability. Clear regulatory frameworks within national and international governance structures, alongside the development of codes of conduct, will be necessary to provide confidence to policymakers and investors and to ensure the inclusive, representative, and just development of oCDR.
The Strategies for the Evaluation and Assessment Of Ocean based Carbon Dioxide Removal (SEAO2-CDR) project seeks to address these concerns by uniting multidisciplinary experts to develop the tools and guidelines needed for deploying oCDR techniques responsibly and transparently.
In conclusion, the ocean represents a significant component of the blue economy with immense potential to aid in achieving carbon neutrality targets. Yet, careful stewardship, close collaboration, and further research are imperative for environmentally safe, socially acceptable, and economically viable deployment of ocean-based carbon dioxide removal techniques.
