A hidden Antarctic shift unleashed the carbon that warmed the world

As the last Ice Age waned and the Holocene dawned, deep-ocean circulation around Antarctica underwent dramatic shifts that helped release long-stored carbon back into the atmosphere. Deep-sea sediments show that ancient Antarctic waters once trapped vast amounts of carbon, only to release it during two major warming pulses at the end of the Ice Age. Understanding these shifts helps scientists predict how modern Antarctic melt may accelerate future climate change.