In the West Antarctic Ice Sheet, which is particularly susceptible to influencing sea levels, rates of mass loss are especially sensitive near the point at which a glacier or ice shelf transitions into a regime of self-sustained retreat. In this state, the effects of ocean warming and other changes are sustained by the dynamics of a retreating ice sheet, with the rate of glacier loss depending strongly on how quickly the ocean melts the ice shelf. These findings are thanks to a team’s research into the processes that regulate basin-wide ice mass loss.