How COP28 can help accelerate research around the ocean's carbon removal potential

While rapid and deep decarbonization of the global economy remains essential for securing a safe climate, the Intergovernmental Panel on Climate Change has made it clear that emission reductions alone will no longer guarantee the avoidance of catastrophic climate change.

Because of the slow pace of progress in reducing emissions, carbon dioxide removal (CDR) is also required to achieve climate targets.

Securing climate safety ultimately requires a net reduction in atmospheric CO2 concentrations from their already high levels today. To achieve this, we must transition from carbon polluter to net zero emissions — and beyond to “net negative.” Essentially, we must clean up the legacy carbon pollution disrupting the global climate system and threatening people worldwide.

Cleaning up carbon pollution can only be done via CDR. If our objective is to secure climate safety, CDR is essential, alongside emissions reductions and adaptation. None of these can be traded for the other. We need all three at the same time.

Legitimate questions remain about whether and to what extent CDR can be feasibly and safely scaled. Answering these questions quickly is imperative; the dire consequences of failure to arrest climate disruption require that we leave no potential tool unstudied. The massive scale of the carbon clean-up challenge, which needs billions of tonnes of CO2 to be removed from the atmosphere and safely stored, necessitates the full array of potential approaches to be considered and deployed.

The ocean may be our greatest ally in this clean-up, given its existing role in the global carbon cycle.

The ocean is already the world’s largest carbon sink, with 50 times more carbon sequestered in the deep ocean than in the atmosphere. There is potential to expand this contribution safely. Because the ocean is so vast, any proven safe and effective approaches could ultimately operate at the massive scale necessary to reduce atmospheric carbon levels meaningfully.

Various marine carbon dioxide removal (mCDR) methods are being explored, broadly divided into two approaches: biotic, which relies on organisms in the ocean to sequester carbon, and abiotic, which doesn’t rely on biological organisms.

Potential methods include adding alkaline minerals or liquids to the ocean to increase uptake of atmospheric CO2; using electrochemistry to strip CO2 from seawater; artificial upwelling or downwelling of ocean water to support photosynthesis or accelerate biomass sinking, spurring the growth of algae through fertilization with nutrients to uptake more carbon; and cultivating carbon-capturing seaweed and ensuring long-term storage of their embedded carbon.

Restoration of coastal ecosystems like mangroves and seagrasses, which are highly efficient carbon sinks and provide many other benefits to people and nature, is also a must.

Despite the ocean’s potential, we lack much-needed data and information, making mCDR a dark horse in the CDR field. While our understanding of different pathways has increased, and small-scale field trials are underway, there are still critical questions about additionality, durability, scalability, cost and safety at climate-relevant scales. The ability to effectively monitor, report and verify the carbon removed through different mCDR solutions is also developing.

With long timelines needed to scale new technologies and solutions, we must move forward quickly to answer these fundamental questions to assess the ocean’s CDR opportunity accurately.

A new road map released by Ocean Visions outlines a comprehensive programme to help prove or disprove the viability of mCDR pathways by 2030. It is grounded by three interconnected pillars: science, technology and policy.

Science is the biggest ticket item. We must design and conduct controlled field trials of each technology in multiple settings at suitably large scales. Each trial must be accompanied by effective third-party monitoring and verification to answer fundamental questions about efficacy and safety.

On the technology front, a great deal of additional brainpower is needed to continue to iterate and optimize mCDR technologies themselves, with new fields and areas of knowledge, such as AI and synbio, brought into the mix to help think about design and scale of workable systems.

Finally, none of this can be done without supportive policy and regulatory frameworks to help facilitate accelerated research and development, alongside efforts to increase political and societal support for action. Given the significant investment and political buy-in required to achieve the necessary testing scale, formal recognition of the criticality of CDR and its potential by national governments and the United Nations Framework Convention on Climate Change is essential.

COP28 is an opportunity to develop and strengthen support for CDR. As the climate emergency intensifies, all nations have a responsibility to speed up significantly and scale their actions to cut emissions as a priority. States can advance the mCDR agenda by committing to collaborate on advancing research and development through financing and creating regulatory frameworks to enable safe research.

Other stakeholders also have key roles to play: scientists and academics are needed to design and engage in field trials, monitoring and conducting relevant social science. NGOs can provide expert advice on equity, justice and biodiversity considerations and hold leaders accountable. Funders can pledge support for scaled research, and the media can bring attention to the latest innovations.

The scale of the decarbonization challenge and the risk of climate breakdown, with its grave implications for all life on Earth, mean that all solutions must be considered. It is a moral imperative to move together quickly to prove, or indeed disprove the role mCDR could play in addressing the climate crisis and securing a safe future.