ABSTRACT: This short note is a validation of a previous work which found no correlation between changes in atmospheric CO2 and fossil fuel emissions at an annual time scale. In this work, this result is tested for robustness with respect to sample period selection within a range of data availability. A resampling procedure similar to bootstrap is used. Resampling ensures that the failure to find a correlation is not an artifact of the sample period chosen. The results validate the robustness of the previous finding and imply that here is no evidence that atmospheric CO2 is responsive to fossil fuel emissions at an annual time scale net of long term trends. This result is robust. It holds for all possible combination of years in the study period 1958-2015.