Scientists are planning to extract ice samples from more than 1.5m years ago in a bid to discover more about our ancient climate – and hopefully learn more about our future climate.

The Beyond Epica project plans to extract samples from the bottom of a 2.75km-thick ice sheet in East Antarctica. The ice cores will be the oldest ever drilled for.

The project, which expects to receive £9.4m in funding from the European commission, is expected to start in June 2020, according to reports in Nature. After two years of extensive research, the international team of scientists has decided to set up camp in an area called Little Dome C, 3.2km above sea level. The British Antarctic Survey says the exact location of the drilling site will be announced on 9 April.

In 2004, drilling for the Epica project unearthed a 3,200-metre-long ice core that was 800,000 years old. This ice fossil indicated the presence of a deep relationship between CO2 levels and global temperatures.

“From these records we know that today’s greenhouse gas concentrations are much higher than anything that has been seen in the past 800,000 years,” said Prof Raimund Muscheler, chair of quaternary sciences at Lund University in Sweden. “This is a very important project because it will help us to better understand the workings of our climate.”

Ice cores are cylindrical logs drilled from ice sheets, and can reveal a lot about the Earth’s ancient climate. Using this information, scientists can learn about the relationship between atmospheric changes and climate, which can then be used to generate models that predict the Earth’s future climate.

“Ice sheets are formed from snowfall buildup over many years – every single snowfall event is trapped as a single, undisturbed layer in the sheet. These layers of snow get progressively thinner as snow is compressed to ice by the addition of more layers of snow,” said Dr Poul Christoffersen, a glaciologist at the Scott Polar Research Institute at the University of Cambridge.

The snow traps air bubbles and dust particles that give a snapshot of the Earth’s atmosphere and climate at a certain time in our past. Described as a “thermometer of the past” by Christoffersen, they also contain information about past temperatures. This is done by comparing the ancient concentrations of gases in successive layers of the ice cores over hundreds of millennia.

Christoffersen says that by using these ice cores, we can go back to times in the past where the Earth had naturally high levels of greenhouse gases.

“Roughly a million years ago, there was a big change in Earth’s climate system called the Mid-Pleistocene Transition,” said Christofferson. “Before that transition, ice ages – or glaciations, as we call them – happened every 40,000 years. Afterwards, and until now, ice ages occurred every 100,000 years.”

“Finding ice that is older than a million years will tell us new things about how climate operated in the past and why there was a shift in the periodicity of glaciation. It may be linked to greenhouse gases such as carbon dioxide, but we don’t know. If it was, it means carbon dioxide and other greenhouse gases can do dramatic things to Earth’s climate,” he said.

Muscheler said knowledge gained from the ice cores would help improve predictions of future climate changes. “It will also help to show that we are on the way to push the climate system outside its natural boundaries,” he said. “Maybe this will help to convince the public and policy makers that urgent action is needed.”