New Research Illuminates Ancient Ocean Currents and Climate Change

A groundbreaking international study, featuring contributions from the University of Birmingham, has unveiled new insights into the evolution of deep ocean currents and their impact on Earth’s climate. Published in Nature Communications on May 9, 2025, the research reveals that the Iceland–Scotland Overflow Water (ISOW), a crucial component of the North Atlantic Deep Water (NADW), intensified around 3.6 million years ago—earlier than previously believed.

The NADW plays a vital role in the Atlantic Meridional Overturning Circulation (AMOC), a system that significantly influences global climate patterns. By analysing sediment cores collected during the International Ocean Discovery Programme (IODP) Expeditions 395C and 395, the research team identified a rapid acceleration in sediment deposition associated with ISOW at the 3.6-million-year mark. This finding suggests a pivotal shift in deep ocean circulation that likely contributed to the long term evolution of Northern Hemisphere climate.

Dr. Tom Dunkley Jones from the University of Birmingham’s School of Geography, Earth and Environmental Sciences played a key role in this study. His expertise in the study of marine algae was instrumental in interpreting the sedimentary records that underpin these conclusions.