Fossilised beaches along the UK coastline have enabled scientists to demonstrate for the first time how melting Antarctic ice sheets impacted global sea levels during a period of pronounced climate warming more than 100,000 years ago.
A study developed at the University of Plymouth, and published in the journal Science Advances, analysed ancient sediments from raised beaches in Cornwall, Devon and elsewhere across Western Europe.
The scientists involved in the research believe the raised beaches – characterised by flat surfaces, often with fossilised beach sands and stones, and typically found around 4–6 metres above current sea levels – could provide an invaluable insight into the local and global impacts of melting ice sheets in the future.
By combining new and existing data with a series of novel analysis and modelling techniques, the team of researchers from the UK, USA and Canada were able to demonstrate that the melting of the Antarctic ice sheet would have caused a rise in global sea levels of up to 5.7 metres.
They reached this conclusion after determining that the sea level change caused by the melting of northern hemisphere ice sheets was largely offset by the fact that removing an ice sheet causes the land near it to rebound. This meant the sea level change recorded on the beaches could only have come from Antarctica.
The researchers were also able to identify the timescale of this change as occurring between 116,000 and 129,000 years ago, ahead of the melting of any ice sheets in the northern hemisphere.
They believe the warmer polar temperatures during this interglacial period make it an important testing ground for understanding how ice sheets respond to warming.