New research published in the September 17 issue of the journal Science sheds light on the evolution of Earth’s climate system by identifying changes in temperature, ocean circulation, and global carbon cycling associated with the rapid growth of Antarctic ice sheets approximately 14 million years ago.
By studying chemical changes in deep sea sediments, scientists at the University of California, Santa Barbara discovered that high-latitude Southern Ocean cooling helped to trigger this major expansion of Antarctic ice sheets, which have since become a permanent feature of the global climate system.
These results document ice sheet history and supply crucial insight into the dynamics of the global climate system.
Scientists have long recognized that the Southern Ocean and the development of Antarctic ice sheets play a major role in the evolution of Earth’s present climate system.
Only now have researchers been able to obtain a clearer picture of the relationship between high-latitude temperatures, global carbon cycling and the size of Antarctic ice sheets.
Southern Ocean temperature data exhibits a rapid 7 degree cooling of surface waters around 14 million years ago and suggests a strengthening of the Antarctic Circumpolar Current in response to changes in the geometry of Earth’s orbits.
As a result, Antarctica became increasingly isolated from tropical heat and moisture sources. Records of Antarctic ice volume indicate that following this cooling ice sheets expanded rapidly to near present-day size, which suggests that changes in the Southern Ocean directly influence the size of the Antarctic ice sheet.
