Sub-ice-shelf sediments record history of twentieth-century retreat of Pine Island Glacier

Many glaciers and ice shelves in the West Antarctic Ice Sheet are retreating or thinning rapidly, but the triggering mechanism has been unclear; now, the retreat of Pine Island Glacier is found to have begun in the 1940s following warming El Nino events in the Pacific Ocean, showing that glacial retreat can continue long after an initial push from the climate.