Is ocean-based carbon removal more useful for adaptation than mitigation?

Why ocean carbon removal is primarily a mitigation strategy

Ocean-based carbon removal works by pulling CO2 out of the atmosphere and storing it in ocean ecosystems or through engineered processes. This directly addresses the root cause of climate change—excess greenhouse gases—which is the definition of mitigation. For example, a 2023 study of mangroves in Indonesia found that tree-level vegetation can absorb up to 7,638 tons of CO2 per hectare, and mangroves overall can absorb 27% more CO2 than the carbon they store [1]. Similarly, a global analysis of mangrove protection showed that safeguarding about 20% of the world's mangroves (2.6 million hectares) could contribute up to 29.8 million tons of CO2 equivalent per year in emissions reductions, with a return on investment of roughly $3.7 billion annually [8]. These are clear mitigation benefits—they reduce the amount of CO2 in the air.

Adaptation, by contrast, means adjusting to the effects of climate change that are already happening or are unavoidable, such as sea-level rise, stronger storms, and ocean acidification. Ocean carbon removal does little to directly address these impacts. A 2022 meta-analysis of 241 marine protected areas (MPAs) found that while MPAs can enhance carbon sequestration and coastal protection, their benefits for adaptation are indirect—for instance, healthy mangroves and seagrasses can buffer coastlines from storm surges, but this is a co-benefit of conservation, not a primary outcome of carbon removal [2]. The same study emphasizes that MPAs alone cannot offset all climate change impacts, and their main contribution is to mitigation and the resilience of social-ecological systems [2].

The distinction matters because policymakers and funders need to allocate resources appropriately. A 2024 policy review of marine carbon dioxide removal (mCDR) explicitly states that coastal and ocean systems cannot be relied upon to deliver significant carbon dioxide removal until further knowledge is acquired, and that their potential impact on mitigation is primarily post-2050 [4]. This means that for near-term adaptation needs—like protecting coastal communities from rising seas—ocean carbon removal is not a practical solution.

What ocean carbon removal can and cannot do for adaptation

While ocean carbon removal is not a direct adaptation tool, some approaches do offer adaptation co-benefits. The most well-established of these is coastal ecosystem restoration—protecting and restoring mangroves, seagrasses, and tidal marshes. These ecosystems not only store carbon (a mitigation benefit) but also provide coastal protection by reducing wave energy and stabilizing shorelines, which is an adaptation benefit. A 2023 study categorizing blue carbon pathways notes that coastal wetlands are the most actionable for mitigation, and their restoration also supports biodiversity and coastal resilience [6]. Public surveys in British Columbia and Washington state found that coastal restoration was the most widely accepted ocean-based carbon removal approach, with high levels of comfort expressed by respondents [7]. This suggests that the public sees value in the dual benefits of these projects.

However, the adaptation benefits are limited and context-dependent. For example, the same study that highlights mangroves' carbon absorption also notes that the mangrove ecosystem studied had only moderate species diversity and low species richness, which can affect its overall health and resilience to climate impacts [1]. A 2022 review of blue carbon science evolution confirms that research attention has shifted from understanding carbon dynamics to focusing on climate change mitigation, not adaptation [3]. Furthermore, emerging approaches like ocean alkalinity enhancement and macroalgae cultivation are still in early stages, with insufficient information to guarantee their climate mitigation benefit, let alone adaptation value [6]. A 2024 historical analysis of ocean carbon sequestration notes that these methods have followed cycles of hype, controversy, and disappointment, and their current resurgence is driven more by new coalitions and narratives than by proven effectiveness [5].

The bottom line: if your goal is to help communities adapt to climate impacts already underway—such as building sea walls, relocating infrastructure, or developing drought-resistant crops—ocean carbon removal is not the right tool. But if your goal is to reduce the long-term severity of climate change, then protecting and restoring coastal blue carbon ecosystems is a proven, cost-effective mitigation strategy that also brings some adaptation co-benefits. The strongest evidence across these studies supports using ocean-based solutions as part of a broader mitigation portfolio, not as a standalone adaptation fix.

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This answer is built on 8 peer-reviewed studies — published from 2021 to 2024, 2 from 2024 or later, 5 in Q1 journals, collectively cited 466 times — selected as the most relevant from 11 studies that passed quality screening, drawn from 55 papers retrieved from a database of over 500 million.

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