We examine the consequences of using four exchange coefficient versus wind speed parameterisations on the air-sea CO2 flux estimation, using one year of satellite wind speed measurements at global scale. Estimates of the global net CO2 flux to the ocean vary from 1.2 to 2.7 GtC yr-1. Additionnaly, we show 1) that the relative importance of outgassing and absorption fluxes is dependent on the form of the relationships due to a correlation between the direction of the flux and wind speed and 2) that differences on global net air-sea flux deduced from different K parameterisations are primarily due to parameterisation differences in the wind speed range between 4 and 17 ms-1.