Collapse of the tropical and subtropical North Atlantic CO2 sink in boreal spring of 2010

Following the 2009 Pacific El Niño, a warm event developed in the tropical and subtropical North Atlantic during boreal spring of 2010 promoted a significant increase in the CO 2 fugacity of surface waters. This, together with the relaxation of the prevailing wind fields, resulted in the reversal of the atmospheric CO 2 absorption capacity of the tropical and subtropical North Atlantic. In the region 0–30°N, 62–10°W, this climatic event led to the reversal of the climatological CO 2 sink of −29.3 Tg C to a source of CO 2 to the atmosphere of 1.6 Tg C from February to May. The highest impact of this event is verified in the region of the North Equatorial Current, where the climatological CO 2 uptake of −22.4 Tg for that period ceased during 2010 (1.2 Tg C). This estimate is higher than current assessments of the multidecadal variability of the sea-air CO 2 exchange for the entire North Atlantic (20 Tg year −1 ), and highlights the potential impact of the increasing occurrence of extreme climate events over the oceanic CO 2 sink and atmospheric CO 2 composition.