The stalagmites of Bàsura Cave in Toirano, one of Liguria’s most important karst and archaeological sites, have enabled researchers to reconstruct one of the fastest episodes of sea-level rise in Earth’s recent history. This is the result of a study published in Nature Communications, carried out through a collaboration between the Xi’an Branch of the Chinese Academy of Sciences, the National Taiwan University in Taipei and a broad international partnership that also included the University of Pisa.
By analysing speleothems—the mineral deposits that form in caves and preserve evidence of past climatic changes—and comparing them with data from the North Atlantic, the researchers reconstructed the mechanism that, around 340,000 years ago, during the so-called Termination IV, caused sea level to rise by as much as five metres per century, one of the highest rates ever documented.
The study shows that this exceptional rise was triggered by a prolonged slowdown of the Atlantic Meridional Overturning Circulation (AMOC), which lasted for approximately 13,000 years. During this period, heat accumulated in the deep ocean. When the circulation resumed, the stored energy was released rapidly, accelerating the melting of the major ice sheets and causing an abrupt rise in sea level.
Professor Elisabetta Starnini and other members of the research team“Bàsura Cave is an extraordinary natural archive for reconstructing past climate,” explains Elisabetta Starnini, Professor of Prehistory and Protohistory in the Department of Civilisations and Forms of Knowledge at the University of Pisa. “The research we are carrying out at this site demonstrates how a place best known for its exceptional archaeological heritage can also make a fundamental contribution to reconstructing the history of Earth’s climate. Understanding how the oceans, ice sheets and atmosphere interacted during the major climatic transitions of the past is essential for interpreting the changes taking place today and improving the tools we use to study the evolution of the Earth’s climate system, particularly in light of the weakening of Atlantic Ocean circulation currently being observed in the context of global warming.”
