The Southern Ocean plays a key role in absorbing carbon dioxide from the atmosphere, but we are still trying to understand exactly how much carbon dioxide the Southern Ocean absorbs and what factors influence this process. The West Antarctic Peninsula is an important area for studying these changes because it is experiencing rapid warming. We looked at changes in the amount of carbon dioxide in the surface ocean water and the amount of microscopic drifting plants (phytoplankton) based on the amount of the pigment Chlorophyll‐a over the past 20 years. Seasonal cycles of both carbon dioxide and Chlorophyll‐a increase from north to south in their amplitude, or their range between the minimum and the maximum each year. In summer, contrary to the effect of warm temperatures which would usually limit carbon uptake by way of physics, strong biological drawdown by phytoplankton dominates the signal.