The Arctic Ocean is undergoing rapid changes due to global warming and the reduction in sea ice, affecting its carbon cycle. Sparse observations of surface partial pressure of CO 2 (pCO 2 ) limit our understanding of these changes. Here, we use continuous fields of surface pCO 2 derived from a gap-filling technique to assess regional and temporal variations in pCO 2 at high latitudes. We find an increase in the annual mean pCO 2 throughout most of the Arctic. However, the rate of change since 2005 varies strongly between regions. By performing a spatio-temporal decomposition via empirical orthogonal function (EOF) analysis, we suggest two primary drivers of seasonal variability, namely solar irradiance correlating negatively with pCO 2 in the sub-Arctic and seasonal variations in the sea-ice cover correlating with the pCO 2 in the high Arctic. Unraveling these dynamics is a crucial step toward better understanding the processes governing the Arctic’s carbon cycle in the future.