Annually‐resolved propagation of CFCs and SF6 in the global ocean over eight decades

CFCs now covering the majority of the global seafloor, according to a new reconstruction of their evolution over the last 8 decades.

(a) Reconstructed chlorofluorocarbon (CFC)-11 arrival time at the ocean floor. The arrival time is defined as the year when CFC-11 first exceeded the detection limit of 0.01 pmol/kg. Values in red indicate areas where CFC-11 values are still below detection limit (i.e., that have not been ventilated yet). Purple arrows indicate some of the major Antarctic Bottom Water (AABW) and North Atlantic Deep Water (NADW) pathways taken from Reid (1994, 1997, 2003). Thin black lines indicate the 3,000 and 4,000 m isobaths. (b) Arrival time along the World Ocean Circulation Experiment (WOCE) sections A10, I05, and P06 (indicated by the black boxes in panel a) as a function of latitude. The dots’ color indicates depth at each location. (Image provided by Jake Gebbie)