1Instituto de Investigaciones Marinas, CSIC, Eduardo Cabello 6, 36208 Vigo, Spain
2IMAGES, Université de Perpignan, 52 avenue Paul Alduy, 66860 Perpignan, France
3LOCEAN/IPSL, Université Pierre et Marie Curie, case 100, 75252 Paris cedex 05, France
4Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, USA
5Bjerknes Centre for Climate Research, University of Bergen, Allégaten 55, 5007 Bergen, Norway
6Geophysical Institute, University of Bergen, Allégaten 70, 5007 Bergen, Norway
Abstract. Five of the most recent observational methods to estimate anthropogenic CO2 (Cant) are applied to a high-quality dataset from five representative sections of the Atlantic Ocean extending from the Arctic to the Antarctic. Between latitudes 60° N–40° S all methods give similar spatial distributions and magnitude of Cant. However, discrepancies are found in some regions, in particular in the Southern Ocean and Nordic Seas. The differences in the Southern Ocean have a significant impact on the anthropogenic carbon inventories. The calculated total inventories of Cant for the Atlantic referred to 1994 vary from 48 to 67 Pg (1015 g) of carbon, with an average of 54±8 Pg C, which is higher than previous estimates. These results, both the detailed Cant distributions and extrapolated inventories, will help to evaluate biogeochemical ocean models and coupled climate-carbon models.