Climate clues in ice

Antarctic core reveals lowest levels of atmospheric carbon dioxide on record

A kilometers-long ice core from Antarctica has recorded climate information for the past 800,000 years and has revealed a three millennia–long period when carbon dioxide levels in the air were lower than any previously measured.

IT’S IN THERE The concentrations of carbon dioxide and methane found in bubbles of ancient air (dark spots) trapped in Antarctic ice provide clues to ancient climate.