INTERNATIONAL CARBON COORDINATION: Roger Revelle's Legacy in the Intergovernmental Oceanographic Commission

Since its inception in 1960, the Intergovernmental Oceanographic Commission (IOC) has been responsible for organizing and coordinating the scientific investigation of ocean carbon. Roger Revelle (Scripps Institution of Oceanography) first articulated the principal need for international and intergovernmental coordination to address global-scale problems such as climate change when IOC was first developed. Regional to global-scale carbon studies started in earnest with the International Decade of Ocean Exploration (IDOE) and Geochemical Ocean Sections Study (GEOSECS) programs in the 1970s, but they were hampered by technological barriers that limited both the precision of carbon system measurements and the greater sampling frequency needed for a comprehensive global view. In 1979, IOC established the Committee on Climate Change and the Ocean (CCCO) with Revelle as Chair. CCCO called for a carbon observation program and sampling strategy that could determine the global oceanic CO₂ inventory to an accuracy of 10–20 petagrams of carbon (Pg C). Perfection of the coulometric analysis technique of total dissolved inorganic carbon (DIC) in seawater by Ken Johnson (University of Rhode Island) and introduction of certified reference materials for DIC and alkalinity by Andrew Dickson (Scripps Institution of Oceanography) made such a study possible. The first global survey of ocean CO₂ was carried out under the joint sponsorship of IOC and the Scientific Committee on Oceanic Research (SCOR) in the Joint Global Ocean Flux Study (JGOFS) and the World Ocean Circulation Experiment (WOCE) in the 1990s. With these programs and underwaypCO₂ measuring systems on research vessels and ships of opportunity, ocean carbon data grew exponentially, reaching about a million total measurements by 2002 when Taro Takahashi (Lamont-Doherty Earth Observatory) and others provided the first robust mapping of surface ocean CO₂. Using a new approach developed by Nicolas Gruber (ETH Zurich) and colleagues with JGOFS-WOCE and other synthesized data sets, one of this article's authors (Sabine) with a host of coauthors estimated that the total accumulation of anthropogenic CO₂ between 1800 and 1994 was 118 ± 19 Pg C, just within the uncertainty goals set by JGOFS and IOC prior to the global survey. Today, ocean carbon activities are coordinated through the International Ocean Carbon Coordination Project (IOCCP). Ocean carbon measurements now accumulate at a rate of over a million measurements per