Ice core reveals longest-ever continuous record of Earth’s climate

A 2.8-kilometre-deep ice core has yielded the longest continuous record of Earth’s climate and atmospheric conditions, stretching back 1.2 million years. Data from the core show how the concentration of carbon dioxide in the atmosphere tracked changes in global temperatures across multiple cycles of climate change. The core covers a period in Earth’s history during which ice ages became less frequent but more brutal. Researchers are hoping the oxygen isotopes and carbon dioxide in the core can provide some hints as to what caused the switch.