Overview

• Long-lost ice core shows large parts of Greenland were ice-free about 400,000 years ago, with climate similar to today.
• Previous assumptions of Greenland being frozen for millions of years have been overturned by the new ice core evidence.
• Past melting during moderate warming suggests Greenland ice sheet is highly sensitive to human-caused climate change.
• Complete melting of Greenland ice sheet could raise global sea levels by around 7 meters (23 feet), with severe impacts.
• The newly analyzed ice core provides evidence of Greenland's warm, ice-free past and highlights concerns about stability of current ice sheet.