STEVE D. JONES, CORINNE LE QUÉRÉ, CHRISTIAN RÖDENBECK, ANDREW C. MANNING, and ARE OLSEN
The world’s oceans absorb approximately 25% of the total anthropogenic emissions of carbon dioxide (CO2) released into the atmosphere every year [MikalofFletcher et al., 2006; Le Quéré et al., 2009]. Understanding oceanic fluxes of CO2 is critical to explain present and project future perturbations of the global carbon cycle caused by human activities. The air-sea fluxes are driven primarily by the difference in the concentration of CO2 between the atmosphere and the ocean surface. The concentration of CO2 in surface water is commonly expressed as either the partial pressure (pCO2) or fugacity (fCO2) of carbon dioxide. Over 10 million surface ocean fCO2 measurements have been collected since 1968 [Takahashi and
Sutherland, 2013; Pfeil et al., 2013; Bakker et al., 2014]. The majority of these measurements have been obtained in the northern hemisphere (Figure 1a) during the past 20 years (Figure 1b), which restricts in-depth analysis of global patterns and long-term trends.