Tracking the increase in surface ocean carbon dioxide with the Surface Ocean CO2 Atlas (SOCAT).

The Surface Ocean CO2 Atlas (SOCAT, www.socat.info) is a synthesis activity by international marine carbon scientists (>100 contributors) with annual public releases. SOCAT documents the increase in surface ocean CO2 (carbon dioxide), as the oceans are taking up about one quarter of the global CO2 emissions from human activity. The current SOCAT version (version 6, released in June 2018) has 23.4 million in situ, quality controlled surface ocean fCO2 (fugacity of CO2) observations for the global oceans and coastal seas from 1957 to 2017, as well as additional calibrated sensor data. SOCAT enables quantification of the ocean carbon sink and ocean acidification, and evaluation of ocean biogeochemical and coupled climate models in a changing world. SOCAT, which celebrated its 10th anniversary in 2017, has made a Voluntary Commitment of annual public releases to the 2017 United Nations Ocean Conference (#OceanAction20464) for SDG (Sustainable Development Goal) 14.3, to 'Minimize and address the impacts of ocean acidification'. The annual SOCAT releases in mid-June are timed to meet requirements for annual updates of the Global Carbon Budget. SOCAT represents a milestone in biogeochemical and climate research and in informing government policy and high-profile climate negotiations. Continuation of the SOCAT effort requires sustained funding. [ABSTRACT FROM AUTHOR]