Direct air capture (DAC) vs. Direct ocean capture (DOC)–A perspective on scale-up demonstrations and environmental relevance to sustain decarbonization

As the atmospheric concentration of CO2 steadily increases and the world grapples with the pressing challenges of global warming, international research communities are actively exploring inventive technologies to combat the adverse effects of elevated CO2 levels. An important challenge in this context is to extract CO2 directly from the atmosphere. Consequently, capturing the last from seawater is crucial due to its impact on the delicate balance of marine ecosystems and the potential consequences for global climate regulation. While DAC and DOC show potential towards combating climate change, challenges including high operational costs and the need for further technological advancements persist. This paper critically discusses the status, challenges, and scalability of DAC and DOC at pilot or industrial scale. Key challenges include capital and operational costs, energy demands, and integrating green energy sources to reduce environmental impact. The review emphasizes on techno-economical benchmarking analyses to evaluate feasibility for large-scale deployment and their effectiveness in mitigating CO2 emissions and acting as tools towards delocalized CO2 production.