Scientists Discover World’s Oldest Ice Core in East Antarctica Almost 1.5 Million Years Old

Scientists claim to have discovered regions in Antarctica that they believe are twice as old as the oldest ice core drilled till date, and which also hold crucial information about earth's ancient climate.

A team of geoscientists have identified regions in East Antarctica dating back nearly 1.5 million years that they believe are a treasure of information about earth's climate and greenhouse gases.

Details of earth's ancient climate trapped in the frozen continent will allow scientists to gain a proper insight into how temperatures respond to the changing concentrations of greenhouse gases in the atmosphere, which will help in predicting the climate change in future.

A report in Discovery claims that by taking a look at the preserved ancient climate the scientists can analyze the air in a key period from 1.2 million -900,000 years ago that is referred as the Mid-Pleistocene Transition.

 "The Mid Pleistocene Transition is a most important and enigmatic time interval in the more recent climate history of our planet," Hubertus Fischer, an experimental climate physics professor at the University of Bern in Switzerland and lead author of the study, said in a press statement.

The scientists measured the levels of carbon dioxide from that period by analyzing the ancient air bubbles trapped inside the ice sheets. The Mid-Pleistocene transition highlighted the point when earth's warming and cooling cycles underwent a significant change. The period of variation before the transition was 41,000 years but later it became 100,000 years. But why the global thermostat cycles reduced continue to remain a mystery.

The climate scientists suspect that this transition took place due to the greenhouse gases. But to confirm this they need to drill into the Antarctic Ice core to get to the 1.5 million years old sample.

"A deep drilling project in Antarctica could commence within the next 3-5 years," Fischer states. "This time would also be needed to plan the drilling logistically and create the funding for such an exciting large-scale international research project, which would cost around 50 million Euros."

It is tricky to get hold of such crucial data that is buried deep in the ice sheet and has remained unaffected from other natural factors.

The study explains that layers of snow on the frozen surface get compressed by the weight of the new snow that falls and it slowly gets transformed into a solid glacier over thousands of years. Due to the weight of the upper ice sheet layers the ice buried deep inside is forced to spread causing the ice layers to get thinner and thinner with depth. This way old ice sheets are preserved in great depths close to the bedrock. But this is challenging as the scientists must ensure that the deep ice is not melting due to the geothermal heat, which would eventually lead to the loss of important data.

"If the ice thickness is too high the old ice at the bottom is getting so warm by geothermal heating that it is melted away," Fischer explains. "This is what happens at Dome C and limits its age to 800,000 years."

The researchers gathered existing data on climate and ice condition in Antarctica to zero in on the possible location where 1.5 million years old ice could be drilled out. They also used a simple ice and heat flow model to find larger areas where old ice may be present. Based on the analysis they believe that the ancient  ice might be present at the bottom of East Antarctica in the region close to the major Domes.

The details are documented in Climate of the Past.