Antarctic Ice Sheet result of global temperature decrease, not continental breakup
A recent study has shown that the Antarctic’s ice sheet and glaciers are a result of decreased carbon dioxide levels 34 million years ago, counteracting studies that suggest immense continental shifts were the primary cause.
The study, published in the journal Nature, raises important issues regarding the effects of global warming, and its obvious impact on the development of the Earth.
As this study suggests, the forming of the highly sensitive ice sheet, which is now declining due to massive hikes in CO2 emissions, could have actually been formed by the cooling of the earth 34 million years ago.
Originally, a 40-year old study known as the Southern Ocean gateway opening, suggested the break-up of modern day Australia and the Antarctic continent caused the creation of the ice sheet. The theory argued that due to the isolation of the continent, caused by its breakup, it became separated from the warm tropical currents that surround Australia – thus causing a dramatic fall in temperature.
“We’ve shown that, instead, CO2-driven cooling initiated the ice sheet and that this altered ocean circulation,” said Matthew Huber of the University of New Hampshire (UNH) Institute for the Study of Earth, Oceans, and Space and department of Earth sciences.
He added, “One of the things we were always missing with our CO2 studies, and it had been missing in everybody’s work, is if conditions are such to make an ice sheet form, perhaps the ice sheet itself is affecting ocean currents and the climate system – that once you start getting an ice sheet to form, maybe it becomes a really active part of the climate system and not just a passive player.”
The investigation led to the finding of a “fingerprint”, or a unique piece of evidence and date, found in deep-sea sediments containing oxygen data from its original development. These fragments of information hold the key to mapping the changes in ocean gateways – and more importantly, what caused them.
The investigation has, however, concluded that the original gateway theory is still relevant, as this may have simply added another reason to why the continents originally broke up, thus creating the ice sheets in the first place.
Photo source: brookpeterson via flickr
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