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Measurements of atmospheric CO2 concentrations were repeatedly carried out on the vessel 'Italica' of the Italian National Research Program in Antarctica, during cruises from Italy to Antarctica. Discrete air samples were also collected in 4-L Pyrex flasks during these cruises in order to carry out delta C-13 analyses on atmospheric CO2. The results acquired between New Zealand and Antarctica are reported here. The mean growth rate of the CO2 concentration from 1996 to 2003 in this area of the Southern Oceans is of about 1.8 ppmv yr(-1), in good agreement with NOAA/CMDL measurements. The rates of increase from cruise to cruise are rather variable. From 1996-1997 to 1998-1999 cruise the yearly growth rate is 2.75 ppmv yr(-1), close to the large growth rates measured in several areas and mainly related to the most severe El Nino event of the last years. The other yearly growth rates are of about 1.3 and 2 ppmv for the periods 1998-1999 to 2001-2002 and 2001-2002 to 2003-2004, respectively. The large difference between these two values is probably related to the uncertainty on the only two 2001-2002 discrete measurements of CO2 concentration in this area. The measured delta C-13 values show two completely different distributions and a large interannual variability. The 1998-1999, 2002-2003, and 2003-2004 results obtained between about 55 degrees S and 65 degrees S across the Antarctic Polar Front show a marked negativization of up to more than 2 parts per thousand when compared to the background values. The results are related to local source regions of CO2, as frequently found in the Southern Ocean by several authors; the negative delta C-13 values are tentatively related to the possible contribution of different causes. Among them, the southward negative gradient of delta C-13 of the dissolved inorganic carbon, the contribution from upwelling deep waters and from subsurface processes between the Northern SubAntarctic Front and the Polar Front, and, partly, the contribution of CO2 of biogenic origin, e.g. from heterotrophic activity. The 2001-2002 results are very homogeneous and almost constant, close to -8.5 parts per thousand, showing only minor deviations from the oceanic background values. This behaviour may be related to differences in the frontal structure along the 2001-2002 track.

CO2 is one of the primary agents of glocal climate changes. the increase of atmospheric CO2 concentration is essentially related to human-induced emissions and particularly to the burning of fossil fuel whos C-delta 13 values are quite negative. Consequently, an increase of the CO2 concentration in the atmosphere should be paralleled by a decrease of its C-delta13. Continuous and/or spot measurements of CO2 concentrations were repeatedly carried out during the last decade and in the same period of the year along hemispheric courses from Italy to Antarctica on a vessel of the Italian national research program in Antarctica. During these expeditions, discrete air samples were also collected in 4-liter Pyrex flasks in order to carry ot precise carbon isotope analyses on atmospheric CO2 from different areas, including theoretically clean open ocean areas, with the main purpose of comparing these open ocean results with the results obtained by the National Oceanic and Atmospheric Administration /World Metorological Organization (NOAA/WMO) at land-based stations. According to the data obtained for these two variables, a relatively large atmospheric pollution is apparent in the Mediterranean area where the CO2 concentration has reached the value of 384 ppmv, while quite negative C-delta 13 values have been measured only occasionally.In this area, southerly winds probably help to reduce the effect of atmospheric pollution even though, despite a large variability of CO2 concentrations, these values are consistently higher than those measured in open ocean areas by a few ppmv to about 10 ppmv. A marked, though non continuous, pollution is apparent in the area of the Ba-el-Mandeb strait where C-delta 13 values considerably more negative than in the Central and Sourhter Red Sea were measured. The concnetration of atmospheric CO2 over the Central Indian Ocean increased from about 361 ppmv at the end of 1996 to about 373 ppmv at the end of 2003 (mean grwoth rate of about 1.7 ppmv yr-1 (yr to the minus 1) in excellent agreement with the NOA/WMO data from land-based stations). Simultaneously, the mean C-delta 13 value of atmospheric CO2 over the Central Indian Ocean (Equator) decreased from -7.92 per mille at the end of 1998 to -8.22 per mille at the end of 2003; the mean decrease rate being about -0.06 per mille yr-1 (yr to the minus 1). This rate as wellas that calculated at 12°S(-0.05 per ille yr-1 (yr to the minus 1)) are not far from the rates that may be calculate according to the data from the nearest NOAA sites (Croset and Mahe islands); the rates calculated south of Australia and between Tasmania and New Zealand are almost identical to those calculated according to the data from Cape Grim NOAA site (Tasmania).