A team of scientists out on an expedition to Antarctica to look for the world’s “oldest ice” this week. The researchers from 10 countries are looking for a frozen core that can provide them with information on changes in climate over the past 1.5 million years. The Beyond EPICA – Oldest Ice project involves scientists from Germany, Britain and France, among other countries.

The scientists are pinning their hopes on the chemistry of the ice and the bubbles of air trapped in the core to help them get a better picture of the change in temperatures. This information will help predict climatic changes the planet can expect to brave in the future. The research is being funded by the European Union.

Dr Robert Mulvaney from the British Antarctic Survey said the research would help scientists understand the aspects of climate change that have yet to be fully explained. “By studying ice that’s 1.5 million years old… we can be absolutely sure that what we are projecting for the next few hundred years is based on a complete knowledge of the science,” he told BBC News.

About a decade ago, when the first chapter of the project was undertaken, researchers drilled around 3,200 metres into the East Antarctic Ice Sheet at a topographic high point known as Dome Concordia. They found small encapsulations of historic greenhouse gases such as CO2, methane, and nitrous oxide. The gases helped them get an idea about changes in temperature going back 80,000 years.

Scientists said the previous endeavour had revealed that ice ages followed a 1,00,000-year cycle, and that temperatures moved in lock-step with carbon dioxide levels. However, ocean sediments tell us that the ice ages had 41,000-year cycle at a point in time around a million years before the time the scientists recorded. Project coordinator Prof Olaf Eisen said, “We have hypotheses of course, but no-one is really certain what the mechanism is that we’re missing.”

Eisen said the missing link that can explain the change in the cycle of the ice ages could be the history of what carbon dioxide and other greenhouse gases were doing at the time. ”But we currently don’t have that record. We know what the temperatures were doing from the stable isotopes in marine cores, but we don’t know about the atmosphere and that should come from the ice,” he said.