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 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 CO 2 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 CO 2 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 underway p CO 2 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 CO 2 . Using a new approach developed by Nicolas Gruber (ETH Zürich) 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 CO 2 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


Roger Revelle's Legacy in the Intergovernmental Oceanographic Commission
Takahashi (Lamont-Doherty Earth Observatory) and others provided the first robust mapping of surface ocean CO 2 . Using a new approach developed by Nicolas Gruber (ETH Zürich) 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 CO 2 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 year-matching the total number achieved over the first three decades of ocean carbon studies. IOCCP is actively working to combine these data into uniform data sets that the community can use to better understand ocean carbon uptake and storage. The problem of ocean acidification caused by uptake of anthropogenic CO 2 is now a major target of IOC and IOCCP.  (Brewer, 1978;Chen and Millero, 1979 " roger reVelle was the first to reCogNize that uNDerstaNDiNg the gigaNtiC geoChemiCal eXperimeNt beiNg CoNDuCteD bY aDDiNg fossil fuel Co 2 to the oCeaN requireD aN iNterNatioNal effort of uNpreCeDeNteD sCale, CompleXitY, aND iNtegratioN. " these approaches were criticized in the literature (e.g., Shiller, 1981;Broecker et al., 1985) and never found general acceptance in the community. Not only were there concerns about the calculation techniques, but there were also concerns about the magnitude of the anthropogenic signal relative to the large natural background of inorganic carbon in the ocean. The estimated accuracy of the GEOSECS measurements was ~ ± 20 µmol kg -1 (e.g., Takahashi et al., 1982 there was concern that ocean CO 2 uptake estimates could not be properly constrained with the limited quality and number of observations available (Broecker et al., 1979;Brewer, 1986). In   The seasonal pCO 2 surveys were prompted by the Tans et al. (1990) publication that combined 30 years worth of shipboard pCO 2 observations in an attempt to develop the first global estimates of air-sea CO 2 fluxes and examine the global carbon budget. This initial work suggested that the ocean sink for CO 2 was only about half of the magnitude inferred from models (e.g., the first-generation, three-dimensional ocean carbon model of Maier-Reimer and Hasselman [1987] or the ocean box model that used GEOSECS data by Bolin et al. [1983]). However, most of the high-  (Poisson et al., 1990a,b). By January 1994, the panel had helped produce the protocols for JGOFS core measurements (JGOFS, 1994) and the CO 2 Methods Handbook (DOE, 1994).
Another important development during the 1990s was introduction of the iron hypothesis-that primary productivity in some regions of the ocean is limited by the availability of certain micronutrients (Martin et al., 1994).
A lack of available iron, an essential micronutrient for primary production, helped explain why there were large ocean regions with high concentrations of macronutrients (e.g., nitrogen, phosphorus) but relatively little productivity as evidenced by low chlorophyll concentrations. From an ocean carbon standpoint, these high nutrient, low chlorophyll (HNLC) regions were also seen as a potential way of explaining the low ice age atmospheric CO 2 concentrations observed by Barnola et al. (1987) based on ice core data (i.e., increased iron dust stimulating ocean uptake of CO 2 during glacial periods) and as an opportunity through an extensive quality assurance procedure, the DIC measurements were estimated to have an overall accuracy of ~ ±2 µmol kg -1 , finally achieving Broecker's prescription (Broecker, 1979;Sabine et al., 2005). However, the international community had yet to achieve the goal of estimating the ocean carbon inventory to ±10-20 Pg C that it had identified nearly two decades earlier.  estimate of 90 Pg C based primarily on the GEOSECS data (Chen, 1993).
However, the large uncertainties associated with this work highlighted the need to improve the measurements and calculation techniques.
While some scientists focused on developing techniques for estimating ocean carbon uptake (e.g., Quay et al., 1992), it was not until nearly 20 years after the original inventory estimation techniques were introduced that a refinement of the anthropogenic CO 2 inventory approach was developed (Gruber et al., 1996;Gruber, 1998). This revised technique together with the newly developed GLODAP synthesized data set allowed Sabine et al. (2004) to estimate that the total accumulation of anthropogenic CO 2 between 1800 and 1994 was 118 ± 19 Pg C, just within the uncertainty goals set by JGOFS and IOC prior to the global survey ( Figure 5).

the iNterNatioNal oCeaN CarboN CoorDiNatioN proJeCt
In the early 2000s, global carbon cycle research again began to accelerate and more countries were becoming involved.  (Figures 3 and 6).
These data, however, still are not sufficient for directly constraining the net annual air-sea exchange globally. As a result, the community is exploring additional novel platforms for collecting data as well as empirical algorithms for extrapolating measurements using remotely sensed data (e.g., Watson et al., 2009