A recent report from the Norwegian University of Science and Technology has highlighted significant risks associated with the use of oceans as carbon sinks. Released during the ongoing UN climate conference COP30 in Brazil, the findings indicate that while the ocean has the potential to absorb carbon dioxide, current technologies are not yet reliable enough for widespread implementation. Experts emphasize the need for strict monitoring and verification before scaling up marine carbon removal technologies.
The report, produced by an expert panel convened by the European Marine Board, argues that rushing into ocean carbon removal could lead to unforeseen environmental challenges. It underscores the urgency of prioritizing emissions reductions as the world approaches the critical 1.5°C threshold for global warming. “We need to strengthen the way we safeguard the oceans before we scale things up,” said Helene Muri, a senior researcher at NILU, the Norwegian Institute for Air Research, and lead author of the report.
Understanding Marine Carbon Removal
Marine carbon dioxide removal aims to utilize the ocean’s natural ability to absorb carbon. This includes biological methods, such as enhancing the growth of plankton and seaweed, which capture carbon during their lifecycle. Other strategies involve chemical or physical techniques that directly extract carbon from seawater. Once captured, carbon can be stored in various locations, including deep-sea sediments and geological formations.
Despite promising advancements, many of these methods still face significant technical and scientific challenges. Muri pointed out that while some marine carbon removal techniques are progressing, they often lack the rigorous standards necessary for monitoring and verification of their effectiveness. “If you cannot verify impacts or where the carbon goes, it becomes difficult to use these methods responsibly,” she noted.
The urgency of the situation was echoed by UN Secretary-General António Guterres during the COP30 Leaders’ Summit. He highlighted the need for immediate action to curb emissions, stating, “The 1.5°C limit is a red line for humanity. It must be kept within reach.”
Balancing Carbon Removal with Emissions Cuts
The report argues that while carbon removal from the oceans may be a necessary part of future climate strategies, it should not distract from the immediate need to reduce emissions. Currently, only certain sectors, such as aviation and shipping, present challenges in terms of achieving zero emissions. To meet global climate targets, countries aim for net-zero emissions by 2050, which will require balancing any remaining emissions with equivalent carbon removal.
Muri explained that achieving the 1.5°C target will likely necessitate net negative emissions, meaning that society must not only eliminate as many emissions as possible but also remove additional carbon dioxide from the atmosphere. According to scenarios provided by the Intergovernmental Panel on Climate Change (IPCC), this could require the removal of between 5 to 10 gigatons of CO2 per year by the end of the century.
Current global CO2 emissions stand at approximately 42.4 gigatons as of 2024, according to the CICERO research institute. Land-based carbon management strategies, such as afforestation and direct air capture technologies, have already shown promise in tackling this issue.
As marine carbon removal technologies continue to evolve, the focus on establishing robust monitoring, reporting, and verification systems becomes crucial. This will help ensure that carbon removal efforts do not inadvertently lead to additional environmental problems, such as biodiversity loss.
Muri emphasized the need for clear guidelines and standards: “We must get serious about the monitoring, reporting, and verification aspects if we want to explore marine carbon dioxide removal responsibly.”
Looking ahead, the report concludes that while marine carbon removal offers potential benefits, it is not a comprehensive solution to climate change. The focus must remain on proven emission reduction strategies first, with careful exploration of ocean-based methods to follow. As Muri aptly put it, “Some people are hoping to find an answer in the ocean, but in our opinion, we’re not there yet.” This cautious approach reflects an understanding that the ocean’s role in climate solutions must be managed with care and vigilance.