The European Marine Board has released a sobering study that cuts through the hopeful rhetoric surrounding climate policy. Its conclusion is stark: oceans alone will not deliver the carbon dioxide reductions needed to reach net zero.
Instead, governments must brace for more spending, more regulation, and more difficult choices if humanity is to keep global warming within the 1.5°C threshold set in Paris a decade ago. The report, “Monitoring, Reporting and Verification for Marine Carbon Dioxide Removal,” was unveiled at COP30 in Brazil. It warns that while oceans can play a role in absorbing carbon, the technologies to harness that potential remain immature, untested at scale, and fraught with uncertainties.
The message is clear: cutting emissions at the source is still the only reliable path forward. Helene Muri, senior scientist at the Norwegian Institute of Air Research and head of the EMB’s working group on marine carbon dioxide removal, has little patience for the idea that oceans can “save the day.”
In an interview with Norwegian SciTech News, she explained that while oceans naturally absorb carbon, turning that process into a dependable climate solution requires technologies that are not yet ready. She described a range of possibilities, from stimulating plankton or seaweed growth to absorb CO2, to extracting carbon directly from seawater, to cultivating kelp and sinking it to the deep ocean.
Other proposals include fertilising the ocean with nutrients to boost phytoplankton growth, pumping nutrient-rich water to the surface, restoring mangroves and seagrasses, mimicking natural rock weathering, enhancing ocean alkalinity, pushing carbon-rich waters deeper, or using electrochemical facilities powered by renewable energy to strip carbon from seawater.
Each of these methods sounds promising in theory, yet Dr Muri stresses that none are mature enough to deploy at scale. Verification is a major obstacle: scientists cannot yet track where the carbon goes, how long it stays sequestered, or what unintended consequences might follow. “This is about safeguarding the oceans for a common good,” she said. “The oceans can be part of the climate solution, but we need to strengthen the way we safeguard them before we scale things up.”
The EMB report underscores that cutting emissions from fossil fuels remains the most urgent priority. Renewable energy sources such as solar and wind are available, scalable, and proven. But some sectors – aviation, shipping, heavy industry – remain stubbornly difficult to decarbonise. Even with aggressive reductions, “residual emissions” will persist. That is why Dr Muri insists societies must aim not just for net zero but for net negative emissions. According to IPCC scenarios, this means removing between five and ten gigatons of CO2 annually by the end of the century. For context, global emissions in 2024 were 42.4 gigatons, according to CICERO, the Oslo-based Centre for International Climate Research. The scale of removal required is daunting, and the EMB warns that oceans cannot shoulder that burden alone.
At COP30, UN Secretary-General Antonio Guterres emphasized the urgency: “Science now tells us that a temporary overshoot beyond the 1.5C limit – starting at the latest in the early 2030s – is inevitable. Let us be clear: the 1.5C limit is a red line for humanity. It must be kept within reach.”
If overshoot is “inevitable,” what role can oceans, technologies, and investment realistically play? The EMB report answers bluntly: oceans cannot deliver salvation on their own. Only aggressive emission cuts, backed by substantial investment in proven renewable technologies, can keep the 1.5C target within reach.
The stakes are high. Without action, experts warn of extreme heat, ecological collapse, economic disruption, and mass displacement by mid-to-late century. The EMB’s insistence on immediate investment reflects the urgency of avoiding these outcomes.
The EMB study is a reminder that oceans are not a silver bullet. They are part of the solution, but not the solution. Policymakers must resist the temptation to pin hopes on unproven technologies while neglecting the hard work of cutting emissions. At the same time, they must make difficult choices about how to finance the transition, which sectors to prioritize, and how to ensure energy security during the shift to renewables.
The path to net zero will require unprecedented spending, innovation, and sustained commitment. It will also require clear communication about what oceans can and cannot do, realistic timelines for emerging technologies, and transparent discussion of the economic and social adjustments ahead. In the end, the EMB report is less a roadmap than a warning: the oceans will not bail us out. Only deliberate and sustained action will. How quickly governments and citizens can mobilize that action remains the defining question of our century.
