With the aid of satellites, we can now very precisely determine how much ice the Greenland and Antarctic ice sheets are losing, and to what extent glaciers around the world are retreating. Their combined ice loss now accounts for roughly two-thirds of global sea-level rise; the remaining third is primarily due to the warming of the oceans, which causes seawater to expand. Accordingly, the development of our planet’s ice sheets and glaciers will to a considerable extent determine what sea levels we should expect to see in the future, and how we can best prepare for them.
The past two decades have shown that the ice masses in Greenland and the Antarctic are highly sensitive to climate warming, and that ice-loss processes have been set in motion that will have lasting consequences. In the Arctic, temperatures are rising twice as quickly as the global average; as a result, the Greenland ice sheet’s loss of mass has accelerated since the 1990s. The record losses observed in 2012, once referred to as a freak event, were surpassed just seven years later, in 2019. In the Antarctic, the development of the extensive ice shelves is of critical importance. Though they currently help to hold back the flow of inland ice, in the future they will most likely shrink, reducing their ability to do so. Currently we still lack the on-site and remote-sensing measurements needed in order to make accurate predictions on the development of the Antarctic ice sheet. These measurements form the basis for a better understanding of the processes involved, and are essential to more accurately estimating the relevant coupling effects.