Ancient marine sediments provide clues to future climate change

Atmospheric carbon dioxide concentration was the major driver behind the global climatic shifts that occurred 53 to 34 million years ago, according to new research led by the University of Southampton, the University of Bristol and Cardiff University. The study is the first to resolve the relationship between carbon dioxide (CO₂) and global temperatures during the period known as the 'Eocene epoch'. This is an important step in understanding ancient climate and thus helping scientists better predict future climate change. The UK-wide research team developed new records of past CO₂ levels by analysing ancient ocean sediments and compared them to previously generated data on ocean temperatures. The results support previously unsubstantiated theories that elevated CO₂ was responsible for the extreme warmth of the early Eocene and that CO₂ decline was responsible for the subsequent cooling that ultimately led to the establishment of today's polar ice sheets. The Bristol team includes Professor Richard Pancost from the University of Bristol and Director of the Cabot Institute, as well as Professor Dan Lunt, Professor Andy Ridgwell, Dr Kirsty Edgar and Dr Gordon Inglis. "We cannot directly measure CO₂ concentrations from that long ago," says Dr Eleni Anagnostou, lead author and postdoctoral researcher at the University of Southampton.