It's nearly summer in Antarctica, and scientists from 10 European countries are now on their way to the world's iciest continent to find the best location to drill for a 1.5-million-year-old chunk of ice core. Given the conditions, they have only a short window to complete their reconnaissance mission—"It's a very remote location and very expensive to put people into," one scientist tells the BBC—but if in the next year or two they can extract a core of the planet's oldest ice, they hope to get answers to pressing questions about established fluctuations in Earth's temperatures as well as past levels of gasses that trap heat, such as carbon dioxide. They're specifically investigating the Pleistocene Epoch, which stretches from 11,700 years ago to 1.8 million years ago, reports Live Science.
The team wants to go back further than the oldest core that's been studied so far, which is 800,000 years old, to understand why more than a million years ago temperature swings changed from 41,000-year cycles to 100,000-year cycles, reports Nature News. A project out of the UK is already starting to drill at "little Dome C" to extract chips of ice and measure temps 650 yards deep, while a French team hopes to probe nearly 2 miles deep next year and a US team hopes to drill on Ross Island next year. All groups are working under the umbrella group International Partnerships in Ice Core Sciences, and say that multiple 1.5-million-year-old core samples would be ideal in understanding how past conditions might shape future changes. (John Kerry recently became the highest-ranked American to visit the continent.)