Study challenges classic view of origin of Antarctic Circumpolar Current, warns of vulnerability

The circumpolar current functions as a regulator of the planet’s climate. Its origins are thought to have caused permanent ice to form in Antarctica around 34 million years ago. Today, a study carried out by the University of Barcelona, ​​the Instituto Andaluz de Ciencias de la Tierra (CSIC) and Imperial College London (UK) has cast doubt on this theory and changed the understanding of how the Antarctic ice sheet developed in the past and what this could mean in the future as the planet’s climate changes.

The article, published in the journal Natural geosciencesbreaks with the classic vision of the origins of the Antarctic Circumpolar Current, the largest marine current on Earth and which is decisive in ocean circulation and climate change.

The most powerful ocean current on the planet

“Until now, it was thought that the polar current stimulated ice formation in Antarctica. Our study reveals that the oceanographic current postdates the start of Antarctic glaciation,” notes Professor Dimitris Evangelinos, first author of the study. study and member of the Consolidated Marine Geosciences Research Group of the Faculty of Earth Sciences at UB and Imperial College London.

“This discovery implies a change of scientific perspective in the field of Antarctic research on the interaction between the polar current and the Antarctic ice,” believes the expert. “The findings reveal that this current is sensitive to changes in climatic conditions, a condition that endangers the climate protection of the frozen supercontinent.”

The article includes the collaboration of the teams of the Paleomagnetism Laboratory of the Scientific and Technological Centers of the UB (CCiTUB) and Geosciences of Barcelona (GEO3BCN-CSIC), the University of Granada, the University of Salamanca and the University of Bordeaux, among others.

A paradigm shift in Antarctic research

The scientific community has debated for years about the origins and characteristics of the Antarctic Circumpolar Current. In addition to connecting the three main basins of the Southern Ocean (Atlantic, Polar and Indian), this mass of polar waters regulates the transport of nutrients and energy to low-latitude regions.

“The Arctic is the planetary region that has the greatest impact on global warming. In Antarctica, the effects are not so intense, and this is due to the thermal insulation generated by the circumpolar current, which prevents warm waters to reach the white continent”, notes Professor Isabel Cacho, from the Department of Terrestrial and Oceanic Dynamics at UB.

This study challenges the most accepted hypothesis that the Antarctic Circumpolar Current appeared once plate tectonics separated the Antarctic continent from the South American continent and opened the Drake and Tasman Passages into the ocean. Southern.

“This means that the Antarctic ice was formed before the existence of the circumpolar current,” explains the researcher. “The new study proves that this circumpolar current is not the origin of the glaciation of Antarctica but the consequence of the formation of the ice.”

The study opens new perspectives for understanding the interaction between the Antarctic Circumpolar Current and the Antarctic ice sheet. “Understanding how these mechanisms work is essential to understanding current and future ocean dynamics and past dynamics of the Southern Ocean, and more importantly, to understanding the challenge of climate change,” the experts conclude.