Ancient antarctic ice key to understanding atmospheric CO2 levels

(UPI) -- Researchers are on the lookout for ancient Antarctic ice to give them a glimpse in to carbon dioxide levels during past ice ages.

The researchers, from the Hobart-based Australian Antarctic Division, claim to have found a region in the East Antarctic Ice Sheet where this ancient ice may exist.

The ice could be 2.5 kilometers below the surface and could date back 1.5 million years. The oldest ice cores extracted so far have been 800,000 years old.

"By understanding how carbon dioxide actually affects the sensitivity of the climate, we'll have a better idea of future changes are going to be in the long term," said Dr. Tas van Ommen.

Scientists are hoping this information will help them better understand how the global climate has changed. For the past 900,000 years the ice ages have come and gone at a frequency of one every 100,000 years. Prior to that, ice ages came every 40,000 years.

“One of the key things is that the ice will give us the carbon-dioxide levels [from that period]," Dr. van Ommen said.

While CO2 levels can be obtained from other sources, including marine sediment, a more categorical estimate can be made using Antarctic ice from that period.

The team's paper, "Where to find 1.5 million-year-old ice," is published in the journal Climate of the Past.