ABSTRACT: Ocean circulation is an important regulator of the physical uptake of carbon dioxide (CO₂) from the atmosphere. However, the magnitude and variability of CO₂ uptake into subtropical mode waters (STMW's), that ventilate the shallow depths of the subtropical gyres, are poorly quantified. Here we report a recent change in the rate of CO₂ uptake into the STMW layer of the North Atlantic Ocean. Since the late 1980's, CO₂ has increased in STMW at a rate double that expected from equilibrium with increasing atmospheric CO₂. We estimate that an extra ~0.6-2.8 Pg (10¹⁵ g) of CO2 has accumulated within the gyre STMW layer, representing ~3-10% (i.e., ~0.03-0.24 Pg C yr-1) of the net annual ocean uptake of CO₂ between 1988 and 2001. The recent change in the oceanic sink of CO₂ into STMW appears coupled to variability of STMW formation and circulation which in turn is primarily associated with climate variability (i.e. North Atlantic Oscillation, NAO). Interannual variability in the uptake of CO₂ into STMW thus provides another factor and feedback controlling the global ocean uptake of CO₂.