English: Estimated annual mean sea surface dissolved inorganic carbon (DIC) for the pre-industrial period (1700s) from the Global Ocean Data Analysis Project (GLODAP) climatology. Original mass units (kg^-1) converted to volume units (m^-3) using the SEAWATER toolbox to calculate density from World Ocean Atlas 2005 fields of temperature and salinity. This field was derived from present day measurements of DIC with the signal of anthropogenic DIC removed by a mathematical technique^[1]. It is plotted here using a Mollweide projection (using MATLAB and the M_Map package).

Note that the GLODAP climatology is missing data in certain oceanic provinces including the Arctic Ocean, the Caribbean Sea, the Mediterranean Sea and the Malay Archipelago.