UPDATE: A critical new report released during COP30 on November 20, 2025, warns of significant risks associated with turning oceans into carbon sinks for climate change mitigation. Experts from the Norwegian University of Science and Technology and the European Marine Board urge immediate caution, stating that current marine carbon removal technologies are not ready for large-scale deployment.
The urgency of this report stems from the alarming reality that the world is nearing the 1.5°C threshold for climate change, a target that must be preserved to avert catastrophic impacts. Helene Muri, a leading researcher at NTNU, emphasizes that while the ocean has the potential to absorb carbon dioxide, “we must safeguard the oceans for a common good” before implementing these unproven technologies.
As the UN climate conference unfolds in Brazil, this report highlights the necessity of monitoring and verification systems to ensure marine carbon removal methods do not inadvertently cause new environmental issues. Current technologies, which include enhancing plankton growth and direct carbon extraction from seawater, remain largely untested and uncertain.
“Science now tells us that a temporary overshoot beyond the 1.5°C limit is inevitable,” said UN Secretary-General António Guterres during the conference, reinforcing the need for immediate and effective emission reductions. Muri concurs, noting that cutting emissions must remain the top priority. “We know how to cut emissions, and we have lots of methods that work,” she stated, insisting that marine solutions should only be considered once clear standards are in place.
The report indicates that to achieve net-zero emissions by 2050, additional strategies, including carbon removal from the atmosphere, must be explored, especially for sectors like aviation, where complete decarbonization is more challenging. The Intergovernmental Panel on Climate Change (IPCC) suggests a need for removing between 5 to 10 gigatons of CO2 annually by century’s end to meet climate targets.
Despite the potential of marine carbon removal, many techniques are still in the early stages, with only a handful undergoing field trials. Establishing robust systems for monitoring and reporting is essential to verify the effectiveness and environmental safety of these methods. Researchers like Muri stress that without reliable tracking, companies cannot responsibly claim carbon offsets for their efforts.
The report calls attention to the critical need for environmental oversight, stating, “If we want to be serious about figuring out if you can do marine carbon dioxide removal responsibly, we need to get serious about monitoring, reporting, and verification.” Muri warns against the temptation to view ocean-based technology as a panacea for climate change, asserting, “We don’t know all the threats of these immature methods yet.”
As discussions continue at COP30, this urgent update serves as a stark reminder of the complexities and responsibilities involved in climate change mitigation. The scientific community continues to advocate for a balanced approach—prioritizing emissions reductions while cautiously exploring innovative solutions.
Readers are encouraged to share this critical information as the world grapples with the pressing challenges of climate change and the role of our oceans in shaping a sustainable future.
