Over the course of the twenty-first century, the subsurface oceans surrounding the Greenland and Antarctic ice sheets are projected to warm by 1.7-2 °C and 0.5-0.6 °C, respectively, concludes a study published online in Nature Geoscience. The projected warming could lead to substantial increases in ice loss, and hence also sea level. Jianjun Yin and colleagues analysed simulations for the twenty-first century with 19 state-of-the-art climate models based on a mid-range emission scenario. They find that at depths between about 200 and 500m, the oceans around both ice sheets are projected to warm substantially beyond the temperature changes observed so far. Warming around Greenland is simulated to be twice as large as the global average, whereas warming near Antarctica is only half as large.