Scientists have discovered a region of Antarctic ice that maybe 1.5 million years old and which could provide clues about earth's past climatic conditions.
This area of Antarctic ice was identified in the East Antarctic Ice Sheet by a team of geologists from the University of Bern. Currently, the oldest ice core discovered dates back to approximately 800,000 years. This geological point falls within a period from 1.2 million to 900,000 years ago, which falls in the Mid-Pleistocene Transition, reports Discovery News. They found that concentrations of heat-trapping greenhouse gases in the atmosphere, such as carbon dioxide, tended to rise with temperature.
"The Mid-Pleistocene Transition is a most important and enigmatic time interval in the more recent climate history of our planet," said the study's lead author, Hubertus Fischer of the University of Bern, Switzerland, in a press release.
Previously, earth witnessed altering extreme warmth and cooling cycles that changed every 41,000 years. However, for the past few thousands of years, these cycles have been altering only every 100,000 years. While previous sediment samples drilled from the bottom of the ocean recorded the temperature differences, scientists weren't able to determine why the global thermostat cycles slowed.
Finding clues about the past atmospheric conditions of earth can be very tricky, even in Antarctica, though this region has an extensive record buried deep in its ice. As snow falls on the frigid continent, it slowly compacts and forms glacial ice. The weight of the ice sheet forces lower, older layers to spread out and become thinner over time. The oldest ice sits near the bedrock.
Based on this theory, scientists concluded that higher sheets of ice could potentially have an older climate history. However, finding high sheets of ice is not enough to gather clues about earth's climatic history. This is because when ice gets too high, geothermal heating can melt the oldest layers of ice. And shifting bedrock can also jumble the annual layers of ice close to the bottom.
The new ice core discovery has led researchers to speculate that greenhouse gases, such as methane and carbon dioxide, may have been the culprits behind the Mid-Pleistocene Transition. However, drills will need to pluck a 2.4 - 3.2 (1.5 - 2 mile)-kilometer-long ice core from the Antarctic ice to give scientists the 1.5 million-year-old sample they need.
"A deep drilling project in Antarctica could commence within the next three to five years," Fischer said, according to Live Science. "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."
