This research has uncovered new insights into past climate fluctuations and ocean currents, particularly the Antarctic Circumpolar Current (ACC), challenging previous assumptions about global climate dynamics and CO2 exchanges between the ocean and atmosphere. Antarctic Circumpolar Current: More Than Just a Global Ocean CurrentThe Antarctic Circumpolar Current (ACC) is the world’s strongest ocean current, connecting the Pacific, Atlantic, and Indian Oceans. It plays a critical role in the circulation of heat, salt, nutrients, and CO2 around Antarctica, influencing global climate patterns. Map with mean annual sea surface temperatures (SST) showing the location of IODP Expedition 383 sites U1543 in the Eastern South Pacific Ocean, U1541 in the Central South Pacific Ocean and other sites discussed in the text. As a result, CO2 was slowly released into the atmosphere, which likely contributed to a cooling of the global climate over time.