A million-year-old ice sample drilled from 3 kilometres under the Antarctic and unveiled in Tokyo on Tuesday could yield vital clues on climate change, Japanese scientists said.
Researchers, showing off the cylindrical samples of what they said was the oldest ice ever to be retrieved, said studying air trapped inside "core" samples taken from various depths under ground could also help predict how the Earth's weather patterns will change in the future.
"The ice core is made up of snow that fell in the distant past," said project leader Hideaki Motoyama of the National Institute of Polar Research, dressed snugly in a parka after unveiling the gleaming ice in a room kept at minus 20 degrees Celsius (minus 4 Fahrenheit).
Researchers at the Dome Fuji base in the eastern Antarctic spent more than two years on the delicate operation of drilling into the ice sheet, coming up with the million-year-old samples in January and shipping them to Japan on an icebreaker.
Research based on a previous study of Antarctic ice and published by Nature magazine last year said concentrations of carbon dioxide and methane were far higher now than at any time in the last 650,000 years. The Japanese team will look farther into the past.