Ice cores taken more than 3km below Antarctica in a region called Dome Concordia (Dome C) shows atmospheric composition as far back as 900,000 years.

Scientists working with the European Project for Ice Coring in Antarctica (Epica) have drilled 3,270 m into the ice, finding that current CO2 levels are unprecedented.

Project leader Thomas Stocker from the University of Bern, Switzerland says: “We find that CO2 is about 30% higher than at any time, and methane 130% higher than at any time; and the rates of increase are absolutely exceptional: for CO2, 200 times faster than at any time in the last 650,000 years.”