(CO

) was absorbed by continental shelf water and was eventually exported into the North Atlantic Ocean. The work confirmed prelimi-nary observations in the same area (2, 3) and provided support for the continental shelf pump hypothesis (4, 5). Thomas et al. then extrapo-lated Bthe CO 2 uptake by the North Sea to the global scale [ and inferred a net oceanic up-take of atmospheric CO 2 by coastal oceans of 0.4 Pg C year–1. A previous global extrapola-tion based on limited observations in the East China Sea (ECS) suggested an even greater air-sea CO 2 flux of 1.0 Pg C year–1 in the world_s continental shelf (4). We are concerned with such extrapolations of re-gional studies to the global scale without cautioning readers that no current consensus exists on this issue. Although most shelf CO 2 measurements have thus far revealed that shelves are sinks of atmospheric CO 2, these shelves are located in mid-latitude zones that experience strong spring blooms and substantial seasonal changes Ei.e., the North Sea (50-N to 61-N) (1, 2), the Gulf of Biscay (42-N to 52-N) (2)