A new report by UNESCO’s Intergovernmental Oceanographic Commission (IOC) reveals a critical lack of knowledge of the process of carbon absorption and storage by the oceans. This great uncertainty about the largest carbon sink on our planet threatens to distort current climate forecasts and hinder our ability to develop effective mitigation and adaptation strategies for decades to come. The report also presents a roadmap to strengthen international cooperation, improve ocean carbon monitoring and update climate patterns accordingly.
« The ocean is one of our most powerful allies in the face of climate change by absorbing a considerable share of the carbon we emit. However, we do not yet have a comprehensive understanding of this natural shield, nor of its ability to endure. It is therefore essential and urgent to put in place a coordinated global monitoring of carbon absorption by the oceans. This report reaffirms UNESCO’s commitment to support Member States in the development of climate policies based on sound scientific data, in order to make progress towards this goal. »
Khaled El-EnanyDirector-General of UNESCO
The ocean stores about 25% of global CO2 emissions. However, according to the new report coordinated by UNESCO’s IOC, our scientific understanding of this process still has significant shortcomings, and variations large enough to significantly influence how governments plan their mitigation and climate change adaptation strategies.
Climate models based on incomplete data
Entitled « Integrated Ocean Carbon Research Report », this report reveals that scientific models differ significantly in their estimates of the amount of carbon absorbed by the oceans, with differences of 10 to 20% globally, or even more in some regions.
These differences are explained by limited access to long-term data and a lack of understanding of the response of key processes to climate change. These include quantifying the impact of ocean warming and circulation on carbon absorption, the influence of changes in planktonic and microbial life on long-term storage, and carbon exchanges between coastal and polar regions and the atmosphere. Current industrial activities and the risks associated with climate engineering in the future could also change the natural ability of the oceans to absorb carbon.
Major consequences for adaptation strategies and climate objectives
All these elements indicate that we are making climate decisions in a context of uncertainty about the future behavior of the ocean. If the ocean absorbs less carbon in the future, a larger share of CO2 will remain in the atmosphere and accelerate global warming. This phenomenon would have a direct impact on future emission reduction targets and national climate plans.
Growing uncertainty about the absorption capacity of carbon also complicates the planning of adaptation measures, especially for coastal communities already weakened by storms, rising sea levels and warming of water. Decisions on potential carbon removal strategies and climate interventions related to the ocean must also be based on stronger scientific bases.
From uncertainty to action
Written by 72 authors from 23 countries, the Integrated Ocean Carbon Research Report offers the most complete summary to date of uncertainties on our estimates of the oceanic carbon sink.
Beyond identifying research needs, the report also presents a coordinated roadmap to strengthen surveillance, modeling and international cooperation so that oceanic carbon science can shed more direct light on climate policy. In order to fill this lack of knowledge, the report advocates the establishment of a global oceanic carbon observation system, combining satellites, autonomous platforms and continuous measurements, from the surface to the depths of the ocean. It also highlights the need to improve ocean and climate modelling, by building capacity in under-represented regions, to ensure truly global surveillance coverage.
Reducing carbon emissions remains the only long-term solution to protect the oceans and the climate. But without a clearer understanding of the evolution of the oceanic carbon sink, global mitigation and adaptation strategies are likely to be developed based on incomplete information.
Since the launch of the United Nations Decade for Ocean Sciences in the Service of Sustainable Development (2021-2030), more than 500 projects have been launched worldwide and more than $1 billion have been mobilized to advance knowledge of the oceans and transform it into measurable actions. Whether strengthening global ocean observation systems, advancing seabed mapping, improving coastal risk early warning systems or supporting ecosystem-based climate solutions, UNESCO’s IOC helps to establish the scientific foundations necessary to protect oceanic biodiversity and strengthen global climate resilience.
source : unesco
