The world ocean is an integral part of the climate system: the coupling processes and feedback mechanisms among atmosphere, ocean, land surface, and cryosphere will determine the features and behavior of the climate system of the future.

Since the industrial revolution, the ocean has evolved into a major sink for carbon generated by human activities. Without oceanic and terrestrial sinks, atmospheric CO2 levels would be close to 600 ppm (parts per million), well above the level compatible with a global warming target limited to 2 ̊C.

In the context of climate change, however, it is still unclear to scientists if the ocean will continue to help mitigate the effects of global warming, or its capacity to absorb carbon from the atmosphere will be altered as a consequence of the numerous human-induced ocean changes.

The world ocean absorbs roughly 28% of the excess CO2 emissions thus acting as the equal second reservoir of anthropogenic CO2 together with terrestrial ecosystems. This comes with a price: the ocean has become significantly more acidic, which can affect the ability of marine organisms such as plankton, mollusks, and reef-building corals to build and maintain shells and skeletal material. The ocean has also warmed significantly in modern times, which has an impact on marine organisms and also on the distribution of oxygen and the emergence of "dead" (extremely poor in oxygen) zones. This more acidic, warmer, and poor in oxygen world ocean has clear effects in terms of reduced ecosystem functioning for ecosystem services such as climate mitigation and food security.

Our work on Climate

The Intergovernmental Oceanographic Commission of UNESCO is at the forefront of climate science and knowledge that inform and underpin meaningful actions to counteract climate change:

  • The World Climate Research Programme (WCRP) – an endeavor of IOC, the World Meteorological Organization (WMO) and the International Science Council (ISC) – acts as an authoritative international platform to craft and implement the next generation of the research agenda on climate and climate change. WCRP is also responsible for developing the models on which the Intergovernmental Panel on Climate Change (IPCC) bases its scenarios and, therefore, negotiations and decisions on climate change are based.
  • IOC conducts work on the effects of CO2 emissions on ocean acidification and acts as a custodian agency for SDG Target Indicator 14.3.1 on ocean acidity.
  • Faced with the urgent need to find answers to this and other crucial scientific questions, five international research programmes on ocean and climate interaction (IOCCP, IMBeR, SOLAS, WCRP/CLIVAR and the Global Carbon Project) have joined IOC to develop and agree on a roadmap for future research, with the ultimate goal of providing decision-makers with the knowledge needed to implement effective climate change mitigation and adaptation policies in the next ten years.
  • IOC, WMO, the International Science Council (ISC) and the UN Environment Programme (UNEP) co-sponsor the Global Ocean Observing System (GOOS), which provides an increasingly comprehensive platform to integrated in situ and remote observations of the status of the world ocean and climate and climate change.
  • The IOC portfolio of activities on early warning systems of tsunami events and other ocean hazards entails inter alia systematic observations of sea level and changes therein, which is of direct relevance to vulnerability and risks of coastal communities and ecosystems related to the effects of climate change.
  • IOC coordinates the International Partnership for Blue Carbon and co-hosts the Blue Carbon Initiative, contributing to climate change mitigation and adaptation, biodiversity and livelihoods.
  • Additionally, the IOC activities aimed at supporting climate adaptation in member states include a well-proven and increasingly widely applied methodology for marine spatial planning, including in relation to multi-stakeholder dialogues based on science that are aimed at developing agreed climate change adaptation plans.

Suggested links

World Climate Research Programme

Ocean Acidification

Integrated Ocean Carbon Research

Blue Carbon