Changes in the Arctic Ocean Carbon Cycle With Diminishing Ice Cover

Less than three decades ago only a small fraction of the Arctic Ocean (AO) was ice free and then only for short periods. The ice cover kept sea surface p CO 2 at levels lower relative to other ocean basins that have been exposed year round to ever increasing atmospheric levels. In this study, we evaluate sea surface p CO 2 measurements collected over a 6‐year period along a fixed cruise track in the Canada Basin. The measurements show that mean p CO 2 levels are significantly higher during low ice years. The p CO 2 increase is likely driven by ocean surface heating and uptake of atmospheric CO 2 with large interannual variability in the contributions of these processes. These findings suggest that increased ice‐free periods will further increase sea surface p CO 2 , reducing the Canada Basin's current role as a net sink of atmospheric CO 2 .