A new study from UNSW Sydney shows that rising ocean temperatures drove melting of the Antarctic ice sheets and cause an extreme sea-level rise more than 100,000 years ago. The team says that a mass melting of the West Antarctica Ice Sheet was a major cause of sea-level rise during a period that is known as the Last Interglacial.
The scientists say that extreme ice loss caused a multi-meter rise in global mean sea levels. According to the study, the ocean temperature increase required for the ice let was only 2C. The team says that fine layers of ancient volcanic ash in the ice helped determine when the melting took place. The results indicated that most ice loss happened in the first millennia.
The fear of the scientists is that such a mass melt could happen again as melting of the ice is already happening with the rising ocean temperatures. During the Last Interglacial polar temperatures were likely 2C warmer than they are today making it an important period to study to determine how future global warming might impact ice levels and sea levels.
One scientist on the team says that the study shows that we could lose most of the West Antarctic Ice Sheet in a warmer world. Much of that ice sheet is surrounded by larger areas of floating ice that protect the central sheet. As warmer water travels into cavities beneath the ice shelves, ice melts from below and thins the shelves making the central ice sheet vulnerable to warming oceans.
The team says that its researcher was conducted on the Patriot Hills Blue Ice Area. That area is perfect for study of this sort because the topography and weather causes ancient ice to rise to the surface. By taking samples here the team found a gap in the ice sheet record immediately prior to the Last Interglacial. The missing ice record corresponds to an extreme sea-level increase.