海洋吸收二氧化碳，并在气候调节中发挥着至关重要的作用。海洋对应的气候调节效应目前尚未得到充分了解。然而，海洋的气候调节能力可能在未来有所衰退，甚至发生角色逆转。当前作为地球“蓝肺”的海洋，最终可能会成为加剧全球变暖的推手。
联合国教科文组织政府间海洋学委员会（简称“海委会”）日前发布了《海洋碳综合研究：海洋碳知识摘要及未来十年海洋碳研究和观测协调展望》报告，提出要完成有关CO2吸收演变的研究。报告概述了有关海洋在碳循环中的作用，并指出未来发展方向。其目的是为决策者制定未来十年减缓和适应气候变化的政策提供所需知识。
报告强调了自工业革命以来，海洋在吸收人类活动产生的碳排放方面发挥的作用。如果没有海洋碳汇和陆地碳汇，大气中的CO2含量将接近600ppm（百万分率），比2019年的410ppm高出50%。后者已远远超出了将全球升温控制在2℃以内这一目标所对应的含量。更为危险的是，海洋碳汇有可能被逆转。海洋不再储碳，还有可能释放CO2，加剧温室效应。为此，海委会的报告分析了现有观测和研究成果，确认海洋能否继续“帮助”人类；或是带来负面影响，使缓解和适应气候变暖的工作愈发艰难。更深刻的问题是，人类如何通过CO2清除计划等手段改变海洋碳循环，以及这对海洋生态系统有何影响。
为编制该报告，海委会召集了来自5个关于海洋与气候相互作用的国际研究和协调项目【国际海洋碳协调计划（IOCCP）、海洋生物圈整合研究计划（IMBeR）、上层海洋-低层大气科学研究计划（SOLAS）、气候变率与可预报性研究计划（CLIVAR）、全球碳计划（GCP）】的专家。自2018年以来，他们一直与海委会海洋碳综合研究工作组开展工作。他们共同提出了一个综合海洋碳汇中期和长期研究的创新型联合计划，以填补这一领域的空白。
该报告是 “联合国海洋科学促进可持续发展国际十年（2021—2030）”的一部分。（节选编辑自联合国教科文组织新闻稿）
In absorbing carbon dioxide (CO2), the oceans play a crucial role in regulating the climate, a role yet to be fully understood. However, the oceans’ ability to contribute to climate regulation may decline and even be reversed in the future. The oceans that are now the blue lungs of our planet, could end up contributing to global warming.
Integrated Ocean Carbon Research: A Summary of Ocean Carbon Knowledge and a Vision for Coordinated Ocean Carbon Research and Observations for the Next Decade, a report newly published by UNESCO’s Intergovernmental Oceanographic Commission (IOC) sets out to accomplish the vital task of studying the evolution of CO2 uptake. It presents a synthesis of the state of knowledge about the oceans’ role in the carbon cycle and points to the way ahead. Its objective is to provide decision-makers with the knowledge needed to develop climate change mitigation and adaptation policies for the coming decade.
The report highlights the role of the ocean since the industrial revolution as a sink for carbon generated by human activity. Indeed, without ocean and land sinks, atmospheric CO2 levels would be close to 600 ppm (parts per million), 50% higher than the 410 ppm recorded in 2019, which is already well above the agreed target of limiting global warming to two degrees Celsius. But there is a danger that this process will be reversed. Instead of absorbing carbon, the oceans could contribute to the warming greenhouse effect of CO2 emissions. The IOC report thus examines available observations and research to determine whether the oceans will continue to “help” humanity or whether they will turn against it, making mitigation and adaptation to warming more difficult. The broader question is how humanity is altering the ocean carbon cycle, including through CO2 removal schemes, and how this impacts marine ecosystems.
In developing the report, the IOC brought together experts from the five international research and coordination programmes on ocean-climate interaction [the International Ocean Carbon Coordination Project (IOCCP), the Integrated Marine Biosphere Research Project (IMBeR), the Surface Ocean – Lower Atmosphere Study (SOLAS), the Climate and Ocean Variability, Predictability and Change (CLIVAR) project and the Global Carbon Project (GCP)], which have been working together since 2018 in the IOC Working Group on Integrated Ocean Carbon Research (IOC-R). Together they propose an innovative joint programme of medium- and long-term integrated ocean carbon research to fill the gaps in this field. The report was developed as part of the ongoing UN Decade of Ocean Sciences for Sustainable Development (2021-2030). (Excerpted and edited from the UNESCO Press Release originally published)
