Ocean carbon uptake and acidification
Anthropogenic carbon dioxide (CO2) emissions have substantially increased atmospheric CO2 concentrations over the last two centuries. Uptake of CO2 by the ocean mitigates the effects of climate change. Observations show that this CO2 causes changes in seawater chemistry, including decreases in seawater pH known as ocean acidification. This process, detrimental to sea life and ocean services, needs to be constantly monitored through sustained ocean observations, in order to develop meaningful projections of future impacts on marine ecosystems, and to implement effective long-term mitigation and adaptation strategies. Ocean acidification has been recognized as vital to sustainable development by the United Nations and the Sustainable Development Goal (SDG) 14(1) and its indicator 14.3.1(2). Under the custodianship of the Intergovernmental Oceanographic Commission (IOC) of UNESCO, this indicator mandates measurement of average marine acidity (pH) at representative sampling sites globally.
Ocean acidification is identified by climate scientists as a Global Climate Indicator – one of a set of climate parameters used to provide key information on climate change. Several JCOMM networks, such as ship based oceanographic measurements, multidisciplinary moorings, autonomous profiling floats and gliders, provide in situ ocean carbonate chemistry measurements, helping to sustain and expand global ocean acidification observations. Ocean acidification observations, following agreed guidelines and best practices, are used by numerous communities, including the Global Ocean Acidification-Observing Network (GOA-ON)(3) and its intergovernmental and international partners(4), to measure changes and indicate trends in the ocean carbon uptake.
Coordinated and continuous monitoring of the global changes in ocean chemistry enable nations to report on the ocean acidification Global Climate Indicator, as well as the United Nations SDG target 14.3.(5)
(1) SDG 14 https://sustainabledevelopment.un.org/sdg14
(2) SDG 14.3.1 indicator methodology http://goa-on.org/resources/sdg_14.3.1_indicator.php
(3) GOA-ON: http://goa-on.org
(4) IOC-UNESCO, the International Ocean Carbon Coordination Project (IOCCP), the Ocean Acidification International Coordination Centre (OA-ICC) of the International Atomic Energy Agency (IAEA) and others
(5) Target 14.3: Minimize and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels.
Ocean Observing System Report Card 2019, Joint Technical Commission for Oceanography and Marine Meteorology (JCOMM) of the World Meteorological Organization (WMO) and UNESCO’s Intergovernmental Oceanographic Commission (IOC). Full Report Card.