Ocean shelf exchange, NW European shelf seas: Measurements, estimates and comparisons

•Volume transports across the NW European shelf edge are large: several m2s−1.•Associated nutrient supply enables a disproportionately strong CO2 “pump”.•The main contributors are wind forcing, Ekman layer below a slope current, tides.•1 m2s−1 across the shelf edge amounts to 500 Sverdrups globally.•Varied observed contexts and processes can validate necessary models.