Sudden loss of tropospheric ozone well above the boundary layer was observed on three occasions at two coastal sites in Antarctica in spring 1995. Back trajectories show that the air sampled the boundary layer near the northern edge of the sea ice (1000 km from the coast) between 3 and 5 days previously. Enhanced BrO observed over sea ice in spring suggests that such ozone loss is common offshore, hence it may cause a small climate effect whose sign would create positive feedback, if sea ice reduced during warming. ¿ 2001 American Geophysical Union