Duk da haka, bayanan ilimin ƙasa sun nuna cewa Duniya ta kasance a wani yanayi mai yawan zafin jiki a duk tsawon tarihinta, kuma cewa duniya ta kasance da ɗan zafi fiye da yadda take a yau. Wani ka'idar tsakanin masana kimiyya ita ce, yanayin duniyar duniyar da ke ƙunshe da isassun iskar gas (kamar carbon dioxide, methane) fiye da yadda suke a yau, wanda ya kama zafi don rama ƙaramin adadin makamashin hasken rana da ya kai shi. Koyaya, binciken da aka yi na Archaean sediments ya bayyana tare da daidaitattun ma'aunin hasken hasken rana na yau da kullun, ya haifar da hasken hasken rana na yau da kullun, wanda zai iya haifar da ƙarancin hasken rana a cikin yanayin hasken rana.
3.8 zuwa 2.5 biliyan shekaru da suka wuce