sample of the week: ice cores

extracted from hundreds or even thousands of metres of accumulated ice and snow, ice cores are a key tool for mapping the Earth's changing climate. the trapped air bubbles, much like the rings of a tree, can be studied to determine the historical atmospheric composition of the planet. the sample above was collected by Dutch scientists from the Oeschger Centre for Climate Change Research in Antarctica to assist with their continued research into concentrations of carbon dioxide, methane and nitrous oxide over the past 800,000 years