Throughout the last ice age, the climate changed repeatedly and rapidly during so-called Dansgaard-Oeschger events, where Greenland temperatures rose between 5 and 16 degrees Celsius in decades. When certain parts of the climate system changed, other parts of the climate system followed like a series of dominos toppling in succession. Today, sea-ice extent is being rapidly reduced, and it is uncertain whether this part of the climate system can trigger sudden future climate change.