Zee Media Bureau
New Delhi: A new study suggests that a drop in carbon dioxide (CO2) levels seems to have triggered Antarctic ice sheet formation.
Roughly a 40 percent decrease in CO2 occurred prior to and during the rapid formation of a mile-thick ice sheet over the Antarctic approximately 34 million years ago.
The long-held, prevailing theory known as "Southern Ocean gateway opening" is not the best explanation for the climate shift that occurred during the Eocene-Oligocene transition when the Earth`s polar regions were ice-free, the study showed.
Matthew Huber of the UNH Institute for the Study of Earth, Oceans, and Space and department of Earth was quoted as saying to a news agency that the Eocene-Oligocene transition was a major event in the history of the planet and their results really flipped the whole story on its head.
“The textbook version had been that gateway opening, in which Australia pulled away from Antarctica, isolated the polar continent from warm tropical currents, and changed temperature gradients and circulation patterns in the ocean around Antarctica, which in turn began to generate the ice sheet. They had shown that, instead, CO2-driven cooling initiated the ice sheet and that this altered ocean circulation” he added.
Huber asserted that one of the things they were always missing with their CO2 studies, and it had been missing in everybody`s work, is if conditions were such to make an ice sheet form, perhaps the ice sheet itself was affecting ocean currents and the climate system that once one start getting an ice sheet to form, maybe it became a really active part of the climate system and not just a passive player.
The study is published in Nature.
(With Agencies inputs)