This decades-long lag between cause and effect is due to the long time it takes to heat the ocean’s huge mass. The energy that is held in the Earth by increased carbon dioxide does more than heat the air. It melts ice; it heats the ocean. Compared to air, it’s harder to raise the temperature of water; it takes time – decades. However, once the ocean temperature is elevated, it will release heat back to the air, and be measured as surface heating.
So even if carbon emissions stopped completely right now, as the oceans’ heating catches up with the atmosphere, the Earth’s temperature would rise about another 0.6℃. Scientists refer to this as committed warming. Ice, also responding to increasing heat in the ocean, will continue to melt. There’s already convincing evidence that significant glaciers in the West Antarctic ice sheets are lost. Ice, water and air – the extra heat held on the Earth by carbon dioxide affects them all. That which has melted will stay melted – and more will melt.