Evidence for a link between rising atmospheric oxygen and the end of an ice age during the Early Palaeoproterozoic is reported in Nature Communications this week. The result supports previous work, which suggests that as the Earth recovered from an ice age this acted to speed up the rise in the atmospheric oxygen levels, and therefore also helps explain the connection between ice ages which occurred 2.5-2.0 billion years ago and the Great Oxidation Event.

Yasuhito Sekine and colleagues analysed Osmium isotopes in sediments dating from during and after the second Palaeoproterozoic ice age. Their findings, from shallow marine environments, suggest increasing atmospheric oxygen levels during this time are in agreement with the hypothesis that the recovery from the ice age accelerated the Great Oxidation Event.